diff --git a/ChangeLog b/ChangeLog
new file mode 100644
index 0000000..791d824
--- /dev/null
+++ b/ChangeLog
@@ -0,0 +1,7 @@
+0.2.0
+-----
+  Refactored API of DSP modules to avoid dynamic memory allocation.
+
+0.1.0
+-----
+  First release.
diff --git a/examples/fx/src/bw_example_fx.c b/examples/fx/src/bw_example_fx.c
index d58ffab..bb441d0 100644
--- a/examples/fx/src/bw_example_fx.c
+++ b/examples/fx/src/bw_example_fx.c
@@ -51,48 +51,36 @@ bw_example_fx bw_example_fx_new() {
 	if (instance == NULL)
 		return NULL;
 
-	instance->svf = bw_svf_new();
-	if (instance->svf == NULL) {
-		BW_FREE(instance);
-		return NULL;
-	}
+	bw_svf_init(&instance->svf);
+	bw_env_follow_init(&instance->env_follow);
 
-	instance->env_follow = bw_env_follow_new();
-	if (instance->env_follow == NULL) {
-		bw_svf_free(instance->svf);
-		BW_FREE(instance);
-		return NULL;
-	}
-
-	bw_one_pole_set_cutoff_down(bw_env_follow_get_one_pole(instance->env_follow), 1.f);
+	bw_one_pole_set_cutoff_down(bw_env_follow_get_one_pole(&instance->env_follow), 1.f);
 	
 	return instance;
 }
 
 void bw_example_fx_free(bw_example_fx instance) {
-	bw_env_follow_free(instance->env_follow);
-	bw_svf_free(instance->svf);
 	BW_FREE(instance);
 }
 
 void bw_example_fx_set_sample_rate(bw_example_fx instance, float sample_rate) {
-	bw_svf_set_sample_rate(instance->svf, sample_rate);
-	bw_env_follow_set_sample_rate(instance->env_follow, sample_rate);
+	bw_svf_set_sample_rate(&instance->svf, sample_rate);
+	bw_env_follow_set_sample_rate(&instance->env_follow, sample_rate);
 }
 
 void bw_example_fx_reset(bw_example_fx instance) {
-	bw_svf_reset(instance->svf);
-	bw_env_follow_reset(instance->env_follow);
+	bw_svf_reset(&instance->svf);
+	bw_env_follow_reset(&instance->env_follow);
 }
 
 void bw_example_fx_process(bw_example_fx instance, const float** x, float** y, int n_samples) {
 	float a[n_samples];
 
-	bw_svf_process(instance->svf, x[0], y[0], NULL, NULL, n_samples);
+	bw_svf_process(&instance->svf, x[0], y[0], NULL, NULL, n_samples);
 
 	for (int i = 0; i < n_samples; i += BUFFER_SIZE) {
 		const uint32_t n = bw_minu32(n_samples - i, BUFFER_SIZE);
-		bw_env_follow_process(instance->env_follow, y[0] + i, instance->buf, n);
+		bw_env_follow_process(&instance->env_follow, y[0] + i, instance->buf, n);
 		instance->level = instance->buf[i + n - 1];
 	}
 }
@@ -100,10 +88,10 @@ void bw_example_fx_process(bw_example_fx instance, const float** x, float** y, i
 void bw_example_fx_set_parameter(bw_example_fx instance, int index, float value) {
 	switch (index) {
 	case p_cutoff:
-		bw_svf_set_cutoff(instance->svf, (20e3f - 20.f) * value * value * value + 20.f);
+		bw_svf_set_cutoff(&instance->svf, (20e3f - 20.f) * value * value * value + 20.f);
 		break;
 	case p_Q:
-		bw_svf_set_Q(instance->svf, 0.5f + 9.5f * value);
+		bw_svf_set_Q(&instance->svf, 0.5f + 9.5f * value);
 		break;
 	}
 }
diff --git a/examples/fx/src/config.h b/examples/fx/src/config.h
index 5b395b6..aa0086c 100644
--- a/examples/fx/src/config.h
+++ b/examples/fx/src/config.h
@@ -50,7 +50,7 @@ struct config_parameter {
 #define COMPANY_MAILTO		"mailto:info@orastron.com"
 
 #define PLUGIN_NAME		"bw_example_fx"
-#define PLUGIN_VERSION		"0.1.0"
+#define PLUGIN_VERSION		"0.2.0"
 
 #define NUM_BUSES_IN		1
 #define NUM_BUSES_OUT		1
diff --git a/examples/synth/src/bw_example_synth.c b/examples/synth/src/bw_example_synth.c
index 7c296a5..beef66e 100644
--- a/examples/synth/src/bw_example_synth.c
+++ b/examples/synth/src/bw_example_synth.c
@@ -48,7 +48,7 @@ struct _bw_example_synth {
 	// Sub-components
 	bw_phase_gen		phase_gen;
 	bw_osc_pulse		osc_pulse;
-	bw_osc_filt	osc_filt;
+	bw_osc_filt		osc_filt;
 	bw_svf			svf;
 	bw_env_gen		env_gen;
 	bw_vol			vol;
@@ -70,108 +70,65 @@ bw_example_synth bw_example_synth_new() {
 	if (instance == NULL)
 		return NULL;
 
-	instance->phase_gen = bw_phase_gen_new();
-	if (instance->phase_gen == NULL)
-		goto err_phase_gen;
+	bw_phase_gen_init(&instance->phase_gen);
+	bw_osc_pulse_init(&instance->osc_pulse);
+	bw_osc_filt_init(&instance->osc_filt);
+	bw_svf_init(&instance->svf);
+	bw_env_gen_init(&instance->env_gen);
+	bw_vol_init(&instance->vol);
+	bw_env_follow_init(&instance->env_follow);
 
-	instance->osc_pulse = bw_osc_pulse_new();
-	if (instance->osc_pulse == NULL)
-		goto err_osc_pulse;
-
-	instance->osc_filt = bw_osc_filt_new();
-	if (instance->osc_filt == NULL)
-		goto err_osc_filt;
-
-	instance->svf = bw_svf_new();
-	if (instance->svf == NULL)
-		goto err_svf;
-
-	instance->env_gen = bw_env_gen_new();
-	if (instance->env_gen == NULL)
-		goto err_env_gen;
-
-	instance->vol = bw_vol_new();
-	if (instance->vol == NULL)
-		goto err_vol;
-
-	instance->env_follow = bw_env_follow_new();
-	if (instance->env_follow == NULL)
-		goto err_env_follow;
-
-	bw_osc_pulse_set_antialiasing(instance->osc_pulse, 1);
-	bw_one_pole_set_cutoff_down(bw_env_follow_get_one_pole(instance->env_follow), 1.f);
+	bw_osc_pulse_set_antialiasing(&instance->osc_pulse, 1);
+	bw_one_pole_set_cutoff_down(bw_env_follow_get_one_pole(&instance->env_follow), 1.f);
 
 	return instance;
-
-err_env_follow:
-	bw_vol_free(instance->vol);
-err_vol:
-	bw_env_gen_free(instance->env_gen);
-err_env_gen:
-	bw_svf_free(instance->svf);
-err_svf:
-	bw_osc_filt_free(instance->osc_filt);
-err_osc_filt:
-	bw_osc_pulse_free(instance->osc_pulse);
-err_osc_pulse:
-	bw_phase_gen_free(instance->phase_gen);
-err_phase_gen:
-	BW_FREE(instance);
-	return NULL;
 }
 
 void bw_example_synth_free(bw_example_synth instance) {
-	bw_env_follow_free(instance->env_follow);
-	bw_vol_free(instance->vol);
-	bw_env_gen_free(instance->env_gen);
-	bw_svf_free(instance->svf);
-	bw_osc_filt_free(instance->osc_filt);
-	bw_osc_pulse_free(instance->osc_pulse);
-	bw_phase_gen_free(instance->phase_gen);
 	BW_FREE(instance);
 }
 
 void bw_example_synth_set_sample_rate(bw_example_synth instance, float sample_rate) {
-	bw_phase_gen_set_sample_rate(instance->phase_gen, sample_rate);
-	bw_osc_pulse_set_sample_rate(instance->osc_pulse, sample_rate);
-	bw_svf_set_sample_rate(instance->svf, sample_rate);
-	bw_env_gen_set_sample_rate(instance->env_gen, sample_rate);
-	bw_vol_set_sample_rate(instance->vol, sample_rate);
-	bw_env_follow_set_sample_rate(instance->env_follow, sample_rate);
+	bw_phase_gen_set_sample_rate(&instance->phase_gen, sample_rate);
+	bw_osc_pulse_set_sample_rate(&instance->osc_pulse, sample_rate);
+	bw_svf_set_sample_rate(&instance->svf, sample_rate);
+	bw_env_gen_set_sample_rate(&instance->env_gen, sample_rate);
+	bw_vol_set_sample_rate(&instance->vol, sample_rate);
+	bw_env_follow_set_sample_rate(&instance->env_follow, sample_rate);
 }
 
 void bw_example_synth_reset(bw_example_synth instance) {
-	bw_phase_gen_reset(instance->phase_gen);
-	bw_osc_pulse_reset(instance->osc_pulse);
-	bw_osc_filt_reset(instance->osc_filt);
-	bw_svf_reset(instance->svf);
-	bw_env_gen_reset(instance->env_gen);
-	bw_vol_reset(instance->vol);
-	bw_env_follow_reset(instance->env_follow);
+	bw_phase_gen_reset(&instance->phase_gen);
+	bw_osc_pulse_reset(&instance->osc_pulse);
+	bw_osc_filt_reset(&instance->osc_filt);
+	bw_svf_reset(&instance->svf);
+	bw_env_gen_reset(&instance->env_gen);
+	bw_vol_reset(&instance->vol);
+	bw_env_follow_reset(&instance->env_follow);
 	instance->note = -1;
 }
 
 void bw_example_synth_process(bw_example_synth instance, const float** x, float** y, int n_samples) {
 	// TODO: I was too lazy to keep track of master tune and note and only update when needed, could be improved
 	if (instance->note != -1) {
-		bw_phase_gen_set_frequency(instance->phase_gen,
+		bw_phase_gen_set_frequency(&instance->phase_gen,
 				440.f * bw_pow2f_3(8.333333333333333e-2f * ((instance->note - 69) + 2.f * instance->params[p_master_tune] - 1.f)));
-		bw_env_gen_set_gate(instance->env_gen, 1);
+		bw_env_gen_set_gate(&instance->env_gen, 1);
 	} else
-		bw_env_gen_set_gate(instance->env_gen, 0);
+		bw_env_gen_set_gate(&instance->env_gen, 0);
 
 	for (int i = 0; i < n_samples; i += BUFFER_SIZE) {
 		float *out = y[0] + i;
 		const uint32_t n = bw_minu32(n_samples - i, BUFFER_SIZE);
-		bw_phase_gen_process(instance->phase_gen, NULL, out, instance->buf, n);
-		bw_osc_pulse_process(instance->osc_pulse, out, instance->buf, out, n);
-		bw_osc_filt_process(instance->osc_filt, out, out, n);
-		bw_svf_process(instance->svf, out, out, NULL, NULL, n);
-		bw_env_gen_process(instance->env_gen, instance->buf, n);
+		bw_phase_gen_process(&instance->phase_gen, NULL, out, instance->buf, n);
+		bw_osc_pulse_process(&instance->osc_pulse, out, instance->buf, out, n);
+		bw_osc_filt_process(&instance->osc_filt, out, out, n);
+		bw_svf_process(&instance->svf, out, out, NULL, NULL, n);
+		bw_env_gen_process(&instance->env_gen, instance->buf, n);
 		for (int j = 0; j < n; j++)
 			out[j] *= instance->buf[j];
-		bw_vol_process(instance->vol, (const float **)&out, &out, 1, n);
-		bw_env_follow_process(instance->env_follow, out, instance->buf, n);
+		bw_vol_process(&instance->vol, (const float **)&out, &out, 1, n);
+		bw_env_follow_process(&instance->env_follow, out, instance->buf, n);
 		instance->level = instance->buf[i + n - 1];
 	}
 }
@@ -179,34 +136,34 @@ void bw_example_synth_process(bw_example_synth instance, const float** x, float*
 void bw_example_synth_set_parameter(bw_example_synth instance, int index, float value) {
 	switch (index) {
 	case p_volume:
-		bw_vol_set_volume(instance->vol, value);
+		bw_vol_set_volume(&instance->vol, value);
 		break;
 	case p_master_tune:
 		instance->params[p_master_tune] = value;
 		break;
 	case p_portamento:
-		bw_phase_gen_set_portamento_tau(instance->phase_gen, value);
+		bw_phase_gen_set_portamento_tau(&instance->phase_gen, value);
 		break;
 	case p_pulse_width:
-		bw_osc_pulse_set_pulse_width(instance->osc_pulse, value);
+		bw_osc_pulse_set_pulse_width(&instance->osc_pulse, value);
 		break;
 	case p_cutoff:
-		bw_svf_set_cutoff(instance->svf, 20.f + (20e3f - 20.f) * value * value * value);
+		bw_svf_set_cutoff(&instance->svf, 20.f + (20e3f - 20.f) * value * value * value);
 		break;
 	case p_Q:
-		bw_svf_set_Q(instance->svf, 0.5f + 9.5f * value);
+		bw_svf_set_Q(&instance->svf, 0.5f + 9.5f * value);
 		break;
 	case p_attack:
-		bw_env_gen_set_attack(instance->env_gen, value);
+		bw_env_gen_set_attack(&instance->env_gen, value);
 		break;
 	case p_decay:
-		bw_env_gen_set_decay(instance->env_gen, value);
+		bw_env_gen_set_decay(&instance->env_gen, value);
 		break;
 	case p_sustain:
-		bw_env_gen_set_sustain(instance->env_gen, value);
+		bw_env_gen_set_sustain(&instance->env_gen, value);
 		break;
 	case p_release:
-		bw_env_gen_set_release(instance->env_gen, value);
+		bw_env_gen_set_release(&instance->env_gen, value);
 		break;
 	}
 }
diff --git a/examples/synth/src/config.h b/examples/synth/src/config.h
index 23d58c6..e69eae4 100644
--- a/examples/synth/src/config.h
+++ b/examples/synth/src/config.h
@@ -50,7 +50,7 @@ struct config_parameter {
 #define COMPANY_MAILTO		"mailto:info@orastron.com"
 
 #define PLUGIN_NAME		"bw_example_synth"
-#define PLUGIN_VERSION		"0.1.0"
+#define PLUGIN_VERSION		"0.2.0"
 
 #define NUM_BUSES_IN		0
 #define NUM_BUSES_OUT		1
diff --git a/include/bw_env_follow.h b/include/bw_env_follow.h
index d57d8d7..1b47aa2 100644
--- a/include/bw_env_follow.h
+++ b/include/bw_env_follow.h
@@ -19,7 +19,7 @@
 
 /*!
  *  module_type {{{ dsp }}}
- *  version {{{ 0.1.0 }}}
+ *  version {{{ 0.2.0 }}}
  *  requires {{{ bw_config bw_common bw_math bw_one_pole }}}
  *  description {{{
  *    Envelope follower made of a full-wave rectifier followed by
@@ -30,6 +30,11 @@
  *  }}}
  *  changelog {{{
  *    <ul>
+ *      <li>Version <strong>0.2.0</strong>:
+ *        <ul>
+ *          <li>Refactored API to avoid dynamic memory allocation.</li>
+ *        </ul>
+ *      </li>
  *      <li>Version <strong>0.1.0</strong>:
  *        <ul>
  *          <li>First release.</li>
@@ -51,34 +56,23 @@ extern "C" {
 /*! api {{{
  *    #### bw_env_follow
  *  ```>>> */
-typedef struct _bw_env_follow *bw_env_follow;
+typedef struct _bw_env_follow bw_env_follow;
 /*! <<<```
- *    Instance handle.
+ *    Instance object.
  *  >>> */
 
 /*! ...
- *    #### bw_env_follow_new()
+ *    #### bw_env_follow_init()
  *  ```>>> */
-bw_env_follow bw_env_follow_new();
+void bw_env_follow_init(bw_env_follow *instance);
 /*! <<<```
- *    Creates a new instance.
- *
- *    Returns the newly-created instance handle or `NULL` if there was not
- *    enough memory.
- *  >>> */
-
-/*! ...
- *    #### bw_env_follow_free()
- *  ```>>> */
-void bw_env_follow_free(bw_env_follow instance);
-/*! <<<```
- *    Destroys an `instance`.
+ *    Initializes the `instance` object.
  *  >>> */
 
 /*! ...
  *    #### bw_env_follow_set_sample_rate()
  *  ```>>> */
-void bw_env_follow_set_sample_rate(bw_env_follow instance, float sample_rate);
+void bw_env_follow_set_sample_rate(bw_env_follow *instance, float sample_rate);
 /*! <<<```
  *    Sets the `sample_rate` (Hz) value for the given `instance`.
  *  >>> */
@@ -86,7 +80,7 @@ void bw_env_follow_set_sample_rate(bw_env_follow instance, float sample_rate);
 /*! ...
  *    #### bw_env_follow_reset()
  *  ```>>> */
-void bw_env_follow_reset(bw_env_follow instance);
+void bw_env_follow_reset(bw_env_follow *instance);
 /*! <<<```
  *    Resets the given `instance` to its initial state.
  *  >>> */
@@ -94,7 +88,7 @@ void bw_env_follow_reset(bw_env_follow instance);
 /*! ...
  *    #### bw_env_follow_process()
  *  ```>>> */
-void bw_env_follow_process(bw_env_follow instance, const float *x, float *y, int n_samples);
+void bw_env_follow_process(bw_env_follow *instance, const float *x, float *y, int n_samples);
 /*! <<<```
  *    Lets the given `instance` process `n_samples` samples from the input
  *    buffer `x` and fills the corresponding `n_samples` samples in the output
@@ -104,13 +98,13 @@ void bw_env_follow_process(bw_env_follow instance, const float *x, float *y, int
 /*! ...
  *    #### bw_env_follow_get_one_pole()
  *  ```>>> */
-bw_one_pole bw_env_follow_get_one_pole(bw_env_follow instance);
+bw_one_pole *bw_env_follow_get_one_pole(bw_env_follow *instance);
 /*! <<<```
- *    Returns the handle to the internal one-pole filter of the given
+ *    Returns a pointer to the internal one-pole filter of the given
  *    `instance`.
  *
- *    The returned handle must not be used for any other purpose than setting
- *    its parameters.
+ *    The returned pointer must not be used for any other purpose than setting
+ *    parameters.
  *
  *    This is **NOT** a function that gets an output parameter as described in
  *    the [documentation for DSP modules](api#dsp).
@@ -121,6 +115,14 @@ bw_one_pole bw_env_follow_get_one_pole(bw_env_follow instance);
  *    [no side effects](api#no-side-effects).
  *  }}} */
 
+/* WARNING: the internal definition of this struct is not part of the public
+ * API. Its content may change at any time in future versions. Please, do not
+ * access its members directly. */
+struct _bw_env_follow {
+	// Sub-components
+	bw_one_pole	one_pole;
+};
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/include/bw_env_gen.h b/include/bw_env_gen.h
index 01f4983..33d90e0 100644
--- a/include/bw_env_gen.h
+++ b/include/bw_env_gen.h
@@ -19,7 +19,7 @@
 
 /*!
  *  module_type {{{ dsp }}}
- *  version {{{ 0.1.0 }}}
+ *  version {{{ 0.2.0 }}}
  *  requires {{{ bw_config bw_common bw_inline_one_pole bw_math }}}
  *  description {{{
  *    Linear ADSR envelope generator.
@@ -39,6 +39,11 @@
  *  }}}
  *  changelog {{{
  *    <ul>
+ *      <li>Version <strong>0.2.0</strong>:
+ *        <ul>
+ *          <li>Refactored API to avoid dynamic memory allocation.</li>
+ *        </ul>
+ *      </li>
  *      <li>Version <strong>0.1.0</strong>:
  *        <ul>
  *          <li>First release.</li>
@@ -58,34 +63,23 @@ extern "C" {
 /*! api {{{
  *    #### bw_env_gen
  *  ```>>> */
-typedef struct _bw_env_gen *bw_env_gen;
+typedef struct _bw_env_gen bw_env_gen;
 /*! <<<```
- *    Instance handle.
+ *    Instance object.
  *  >>> */
 
 /*! ...
- *    #### bw_env_gen_new()
+ *    #### bw_env_gen_init()
  *  ```>>> */
-bw_env_gen bw_env_gen_new();
+void bw_env_gen_init(bw_env_gen *instance);
 /*! <<<```
- *    Creates a new instance.
- *
- *    Returns the newly-created instance handle or `NULL` if there was not
- *    enough memory.
- *  >>> */
-
-/*! ...
- *    #### bw_env_gen_free()
- *  ```>>> */
-void bw_env_gen_free(bw_env_gen instance);
-/*! <<<```
- *    Destroys an `instance`.
+ *    Initializes the `instance` object.
  *  >>> */
 
 /*! ...
  *    #### bw_env_gen_set_sample_rate()
  *  ```>>> */
-void bw_env_gen_set_sample_rate(bw_env_gen instance, float sample_rate);
+void bw_env_gen_set_sample_rate(bw_env_gen *instance, float sample_rate);
 /*! <<<```
  *    Sets the `sample_rate` (Hz) value for the given `instance`.
  *  >>> */
@@ -93,7 +87,7 @@ void bw_env_gen_set_sample_rate(bw_env_gen instance, float sample_rate);
 /*! ...
  *    #### bw_env_gen_reset()
  *  ```>>> */
-void bw_env_gen_reset(bw_env_gen instance);
+void bw_env_gen_reset(bw_env_gen *instance);
 /*! <<<```
  *    Resets the given `instance` to its initial state.
  *  >>> */
@@ -101,7 +95,7 @@ void bw_env_gen_reset(bw_env_gen instance);
 /*! ...
  *    #### bw_env_gen_process()
  *  ```>>> */
-void bw_env_gen_process(bw_env_gen instance, float* y, int n_samples);
+void bw_env_gen_process(bw_env_gen *instance, float* y, int n_samples);
 /*! <<<```
  *    Lets the given `instance` generate `n_samples` samples and puts them in
  *    the output buffer `y`.
@@ -110,7 +104,7 @@ void bw_env_gen_process(bw_env_gen instance, float* y, int n_samples);
 /*! ...
  *    #### bw_env_gen_set_gate()
  *  ```>>> */
-void bw_env_gen_set_gate(bw_env_gen instance, char value);
+void bw_env_gen_set_gate(bw_env_gen *instance, char value);
 /*! <<<```
  *    Sets the input gate to be either off (`0`) or on (non-`0`) for the given
  *    `instance`.
@@ -121,7 +115,7 @@ void bw_env_gen_set_gate(bw_env_gen instance, char value);
 /*! ...
  *    #### bw_env_gen_set_attack()
  *  ```>>> */
-void bw_env_gen_set_attack(bw_env_gen instance, float value);
+void bw_env_gen_set_attack(bw_env_gen *instance, float value);
 /*! <<<```
  *    Sets the attack time to `value` (s) for the given `instance`.
  *
@@ -133,7 +127,7 @@ void bw_env_gen_set_attack(bw_env_gen instance, float value);
 /*! ...
  *    #### bw_env_gen_set_decay()
  *  ```>>> */
-void bw_env_gen_set_decay(bw_env_gen instance, float value);
+void bw_env_gen_set_decay(bw_env_gen *instance, float value);
 /*! <<<```
  *    Sets the decay time to `value` (s) for the given `instance`.
  *
@@ -145,7 +139,7 @@ void bw_env_gen_set_decay(bw_env_gen instance, float value);
 /*! ...
  *    #### bw_env_gen_set_sustain()
  *  ```>>> */
-void bw_env_gen_set_sustain(bw_env_gen instance, float value);
+void bw_env_gen_set_sustain(bw_env_gen *instance, float value);
 /*! <<<```
  *    Sets the sustain level to `value` for the given `instance`.
  *
@@ -155,7 +149,7 @@ void bw_env_gen_set_sustain(bw_env_gen instance, float value);
 /*! ...
  *    #### bw_env_gen_set_release()
  *  ```>>> */
-void bw_env_gen_set_release(bw_env_gen instance, float value);
+void bw_env_gen_set_release(bw_env_gen *instance, float value);
 /*! <<<```
  *    Sets the release time to `value` (s) for the given `instance`.
  *
@@ -167,11 +161,46 @@ void bw_env_gen_set_release(bw_env_gen instance, float value);
 /*! ...
  *    #### bw_env_gen_get_is_off()
  *  ```>>> */
-char bw_env_gen_get_is_off(bw_env_gen instance);
+char bw_env_gen_get_is_off(bw_env_gen *instance);
 /*! <<<```
  *    Returns `0` if the given `instance` is in the off state, non-`0` otherwise.
  *  }}} */
 
+/* WARNING: this enum is not part of the public API. Please, do not use it. */
+typedef enum {
+	_bw_env_gen_state_off,
+	_bw_env_gen_state_attack,
+	_bw_env_gen_state_decay,
+	_bw_env_gen_state_sustain,
+	_bw_env_gen_state_release
+} _bw_env_gen_state;
+
+/* WARNING: the internal definition of this struct is not part of the public
+ * API. Its content may change at any time in future versions. Please, do not
+ * access its members directly. */
+struct _bw_env_gen {
+	// Coefficients
+	float			T;
+	float			smooth_mA1;
+
+	float			attack_inc;
+	float			decay_inc;
+	float			release_inc;
+
+	// Parameters
+	char			gate;
+	float			attack;
+	float			decay;
+	float			sustain;
+	float			release;
+	int			param_changed;
+
+	// State
+	char			first_run;
+	_bw_env_gen_state	state;
+	float			y_z1;
+};
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/include/bw_noise_gen.h b/include/bw_noise_gen.h
index dadd03a..3f6a86b 100644
--- a/include/bw_noise_gen.h
+++ b/include/bw_noise_gen.h
@@ -19,13 +19,18 @@
 
 /*!
  *  module_type {{{ dsp }}}
- *  version {{{ 0.1.0 }}}
+ *  version {{{ 0.2.0 }}}
  *  requires {{{ bw_config bw_common bw_math bw_rand }}}
  *  description {{{
  *    Generator of white noise with uniform distribution.
  *  }}}
  *  changelog {{{
  *    <ul>
+ *      <li>Version <strong>0.2.0</strong>:
+ *        <ul>
+ *          <li>Refactored API to avoid dynamic memory allocation.</li>
+ *        </ul>
+ *      </li>
  *      <li>Version <strong>0.1.0</strong>:
  *        <ul>
  *          <li>First release.</li>
@@ -47,35 +52,24 @@ extern "C" {
 /*! api {{{
  *    #### bw_noise_gen
  *  ```>>> */
-typedef struct _bw_noise_gen *bw_noise_gen;
+typedef struct _bw_noise_gen bw_noise_gen;
 /*! <<<```
- *    Instance handle.
+ *    Instance object.
  *  >>> */
 
 /*! ...
- *    #### bw_noise_gen_new()
+ *    #### bw_noise_gen_init()
  *  ```>>> */
-bw_noise_gen bw_noise_gen_new(uint64_t *state);
+void bw_noise_gen_init(bw_noise_gen *instance, uint64_t *state);
 /*! <<<```
- *    Creates a new instance which uses the given `state` pointer to obtain
- *    pseudo-random numbers.
- *
- *    Returns the newly-created instance handle or `NULL` if there was not
- *    enough memory.
- *  >>> */
-
-/*! ...
- *    #### bw_noise_gen_free()
- *  ```>>> */
-void bw_noise_gen_free(bw_noise_gen instance);
-/*! <<<```
- *    Destroys an `instance`.
+ *    Initializes the `instance` object and lets it use the given `state`
+ *    pointer to obtain pseudo-random numbers.
  *  >>> */
 
 /*! ...
  *    #### bw_noise_gen_set_sample_rate()
  *  ```>>> */
-void bw_noise_gen_set_sample_rate(bw_noise_gen instance, float sample_rate);
+void bw_noise_gen_set_sample_rate(bw_noise_gen *instance, float sample_rate);
 /*! <<<```
  *    Sets the `sample_rate` value for the given `instance`.
  *  >>> */
@@ -89,7 +83,7 @@ void bw_noise_gen_set_sample_rate(bw_noise_gen instance, float sample_rate);
 /*! ...
  *    #### bw_noise_gen_process()
  *  ```>>> */
-void bw_noise_gen_process(bw_noise_gen instance, float* y, int n_samples);
+void bw_noise_gen_process(bw_noise_gen *instance, float* y, int n_samples);
 /*! <<<```
  *    Lets the given `instance` generate `n_samples` samples and puts them in
  *    the output buffer `y`.
@@ -98,7 +92,7 @@ void bw_noise_gen_process(bw_noise_gen instance, float* y, int n_samples);
 /*! ...
  *    #### bw_noise_gen_set_sample_rate_scaling()
  *  ```>>> */
-void bw_noise_gen_set_sample_rate_scaling(bw_noise_gen instance, char value);
+void bw_noise_gen_set_sample_rate_scaling(bw_noise_gen *instance, char value);
 /*! <<<```
  *    Sets whether the output should be scaled (`value` non-`0`) or not (`0`)
  *    according to the sample rate by the given `instance`.
@@ -111,6 +105,20 @@ void bw_noise_gen_set_sample_rate_scaling(bw_noise_gen instance, char value);
  *    Default value: `0`.
  *  }}} */
 
+/* WARNING: the internal definition of this struct is not part of the public
+ * API. Its content may change at any time in future versions. Please, do not
+ * access its members directly. */
+struct _bw_noise_gen {
+	// Coefficients
+	float		 scaling_k;
+
+	// Parameters
+	char		 sample_rate_scaling;
+
+	// State
+	uint64_t	*state;
+};
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/include/bw_one_pole.h b/include/bw_one_pole.h
index 2d41a23..b2fa1c4 100644
--- a/include/bw_one_pole.h
+++ b/include/bw_one_pole.h
@@ -19,7 +19,7 @@
 
 /*!
  *  module_type {{{ dsp }}}
- *  version {{{ 0.1.0 }}}
+ *  version {{{ 0.2.0 }}}
  *  requires {{{ bw_config bw_common bw_math }}}
  *  description {{{
  *    One-pole (6 dB/oct) lowpass filter with unitary DC gain, separate attack
@@ -27,6 +27,11 @@
  *  }}}
  *  changelog {{{
  *    <ul>
+ *      <li>Version <strong>0.2.0</strong>:
+ *        <ul>
+ *          <li>Refactored API to avoid dynamic memory allocation.</li>
+ *        </ul>
+ *      </li>
  *      <li>Version <strong>0.1.0</strong>:
  *        <ul>
  *          <li>First release.</li>
@@ -46,9 +51,9 @@ extern "C" {
 /*! api {{{
  *    #### bw_one_pole
  *  ```>>> */
-typedef struct _bw_one_pole *bw_one_pole;
+typedef struct _bw_one_pole bw_one_pole;
 /*! <<<```
- *    Instance handle.
+ *    Instance object.
  *  >>> */
  
 /*! ...
@@ -66,28 +71,17 @@ typedef enum {
  *  >>> */
 
 /*! ...
- *    #### bw_one_pole_new()
+ *    #### bw_one_pole_init()
  *  ```>>> */
-bw_one_pole bw_one_pole_new();
+void bw_one_pole_init(bw_one_pole *instance);
 /*! <<<```
- *    Creates a new instance.
- *
- *    Returns the newly-created instance handle or `NULL` if there was not
- *    enough memory.
- *  >>> */
-
-/*! ...
- *    #### bw_one_pole_free()
- *  ```>>> */
-void bw_one_pole_free(bw_one_pole instance);
-/*! <<<```
- *    Destroys an `instance`.
+ *    Initializes the `instance` object.
  *  >>> */
 
 /*! ...
  *    #### bw_one_pole_set_sample_rate()
  *  ```>>> */
-void bw_one_pole_set_sample_rate(bw_one_pole instance, float sample_rate);
+void bw_one_pole_set_sample_rate(bw_one_pole *instance, float sample_rate);
 /*! <<<```
  *    Sets the `sample_rate` (Hz) value for the given `instance`.
  *  >>> */
@@ -95,7 +89,7 @@ void bw_one_pole_set_sample_rate(bw_one_pole instance, float sample_rate);
 /*! ...
  *    #### bw_one_pole_reset()
  *  ```>>> */
-void bw_one_pole_reset(bw_one_pole instance);
+void bw_one_pole_reset(bw_one_pole *instance);
 /*! <<<```
  *    Resets the given `instance` to its initial state.
  *  >>> */
@@ -103,7 +97,7 @@ void bw_one_pole_reset(bw_one_pole instance);
 /*! ...
  *    #### bw_one_pole_process()
  *  ```>>> */
-void bw_one_pole_process(bw_one_pole instance, const float* x, float* y, int n_samples);
+void bw_one_pole_process(bw_one_pole *instance, const float* x, float* y, int n_samples);
 /*! <<<```
  *    Lets the given `instance` process `n_samples` samples from the input
  *    buffer `x` and fills the corresponding `n_samples` samples in the output
@@ -113,7 +107,7 @@ void bw_one_pole_process(bw_one_pole instance, const float* x, float* y, int n_s
 /*! ...
  *    #### bw_one_pole_set_init_val()
  *  ```>>> */
-void bw_one_pole_set_init_val(bw_one_pole instance, float value);
+void bw_one_pole_set_init_val(bw_one_pole *instance, float value);
 /*! <<<```
  *    Sets the initial/quiescent `value` for the given `instance`.
  *
@@ -127,7 +121,7 @@ void bw_one_pole_set_init_val(bw_one_pole instance, float value);
 /*! ...
  *    #### bw_one_pole_set_cutoff()
  *  ```>>> */
-void bw_one_pole_set_cutoff(bw_one_pole instance, float value);
+void bw_one_pole_set_cutoff(bw_one_pole *instance, float value);
 /*! <<<```
  *    Sets both the upgoing (attack) and downgoing (decay) cutoff frequency to
  *    the given `value` (Hz) for the given `instance`.
@@ -143,7 +137,7 @@ void bw_one_pole_set_cutoff(bw_one_pole instance, float value);
 /*! ...
  *    #### bw_one_pole_set_cutoff_up()
  *  ```>>> */
-void bw_one_pole_set_cutoff_up(bw_one_pole instance, float value);
+void bw_one_pole_set_cutoff_up(bw_one_pole *instance, float value);
 /*! <<<```
  *    Sets the upgoing (attack) cutoff frequency to the given `value` (Hz) for
  *    the given `instance`.
@@ -157,7 +151,7 @@ void bw_one_pole_set_cutoff_up(bw_one_pole instance, float value);
 /*! ...
  *    #### bw_one_pole_set_cutoff_down()
  *  ```>>> */
-void bw_one_pole_set_cutoff_down(bw_one_pole instance, float value);
+void bw_one_pole_set_cutoff_down(bw_one_pole *instance, float value);
 /*! <<<```
  *    Sets the downgoing (attack) cutoff frequency to the given `value` (Hz)
  *    for the given `instance`.
@@ -171,7 +165,7 @@ void bw_one_pole_set_cutoff_down(bw_one_pole instance, float value);
 /*! ...
  *    #### bw_one_pole_set_tau()
  *  ```>>> */
-void bw_one_pole_set_tau(bw_one_pole instance, float value);
+void bw_one_pole_set_tau(bw_one_pole *instance, float value);
 /*! <<<```
  *    Sets both the upgoing (attack) and downgoing (decay) time constant to the
  *    given `value` (s) for the given `instance`.
@@ -187,7 +181,7 @@ void bw_one_pole_set_tau(bw_one_pole instance, float value);
 /*! ...
  *    #### bw_one_pole_set_tau_up()
  *  ```>>> */
-void bw_one_pole_set_tau_up(bw_one_pole instance, float value);
+void bw_one_pole_set_tau_up(bw_one_pole *instance, float value);
 /*! <<<```
  *    Sets the upgoing (attack) time constant to the given `value` (s) for the
  *    given `instance`.
@@ -201,7 +195,7 @@ void bw_one_pole_set_tau_up(bw_one_pole instance, float value);
 /*! ...
  *    #### bw_one_pole_set_tau_down()
  *  ```>>> */
-void bw_one_pole_set_tau_down(bw_one_pole instance, float value);
+void bw_one_pole_set_tau_down(bw_one_pole *instance, float value);
 /*! <<<```
  *    Sets the downgoing (decay) time constant to the given `value` (s) for the
  *    given `instance`.
@@ -215,7 +209,7 @@ void bw_one_pole_set_tau_down(bw_one_pole instance, float value);
 /*! ...
  *    #### bw_one_pole_set_sticky_thresh()
  *  ```>>> */
-void bw_one_pole_set_sticky_thresh(bw_one_pole instance, float value);
+void bw_one_pole_set_sticky_thresh(bw_one_pole *instance, float value);
 /*! <<<```
  *    Sets the target-reach threshold specified by `value` for the given
  *    `instance`.
@@ -231,11 +225,36 @@ void bw_one_pole_set_sticky_thresh(bw_one_pole instance, float value);
 /*! ...
  *    #### bw_one_pole_set_sticky_mode()
  *  ```>>> */
-void bw_one_pole_set_sticky_mode(bw_one_pole instance, bw_one_pole_sticky_mode value);
+void bw_one_pole_set_sticky_mode(bw_one_pole *instance, bw_one_pole_sticky_mode value);
 /*! <<<```
  *    Sets the current distance metric for sticky behavior.
  *  }}} */
 
+/* WARNING: the internal definition of this struct is not part of the public
+ * API. Its content may change at any time in future versions. Please, do not
+ * access its members directly. */
+struct _bw_one_pole {
+	// Coefficients
+	float			Ttm2pi;
+
+	float			mA1u;
+	float			mA1d;
+	float			st2;
+
+	// Parameters
+	float			init_val;
+	float			cutoff_up;
+	float			cutoff_down;
+	float			sticky_thresh;
+	bw_one_pole_sticky_mode sticky_mode;
+	int			param_changed;
+
+	// State
+	char			first_run;
+	float			x_z1;
+	float			y_z1;
+};
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/include/bw_osc_filt.h b/include/bw_osc_filt.h
index 03f2c55..797fef8 100644
--- a/include/bw_osc_filt.h
+++ b/include/bw_osc_filt.h
@@ -19,7 +19,7 @@
 
 /*!
  *  module_type {{{ dsp }}}
- *  version {{{ 0.1.0 }}}
+ *  version {{{ 0.2.0 }}}
  *  requires {{{ bw_config bw_common }}}
  *  description {{{
  *    Post-filter to decolorate oscillator waveshapers when antialiasing is on.
@@ -31,6 +31,11 @@
  *  }}}
  *  changelog {{{
  *    <ul>
+ *      <li>Version <strong>0.2.0</strong>:
+ *        <ul>
+ *          <li>Refactored API to avoid dynamic memory allocation.</li>
+ *        </ul>
+ *      </li>
  *      <li>Version <strong>0.1.0</strong>:
  *        <ul>
  *          <li>First release.</li>
@@ -50,28 +55,17 @@ extern "C" {
 /*! api {{{
  *    #### bw_osc_filt
  *  ```>>> */
-typedef struct _bw_osc_filt *bw_osc_filt;
+typedef struct _bw_osc_filt bw_osc_filt;
 /*! <<<```
- *    Instance handle.
+ *    Instance object.
  *  >>> */
 
 /*! ...
- *    #### bw_osc_filt_new()
+ *    #### bw_osc_filt_init()
  *  ```>>> */
-bw_osc_filt bw_osc_filt_new();
+void bw_osc_filt_init(bw_osc_filt *instance);
 /*! <<<```
- *    Creates a new instance.
- *
- *    Returns the newly-created instance handle or `NULL` if there was not
- *    enough memory.
- *  >>> */
-
-/*! ...
- *    #### bw_osc_filt_free()
- *  ```>>> */
-void bw_osc_filt_free(bw_osc_filt instance);
-/*! <<<```
- *    Destroys an `instance`.
+ *    Initializes the `instance` object.
  *  >>> */
 
 /*! ...
@@ -83,7 +77,7 @@ void bw_osc_filt_free(bw_osc_filt instance);
 /*! ...
  *    #### bw_osc_filt_reset()
  *  ```>>> */
-void bw_osc_filt_reset(bw_osc_filt instance);
+void bw_osc_filt_reset(bw_osc_filt *instance);
 /*! <<<```
  *    Resets the given `instance` to its initial state.
  *  >>> */
@@ -91,7 +85,7 @@ void bw_osc_filt_reset(bw_osc_filt instance);
 /*! ...
  *    #### bw_osc_filt_process()
  *  ```>>> */
-void bw_osc_filt_process(bw_osc_filt instance, const float *x, float* y, int n_samples);
+void bw_osc_filt_process(bw_osc_filt *instance, const float *x, float* y, int n_samples);
 /*! <<<```
  *    Lets the given `instance` process `n_samples` samples from the input
  *    buffer `x` and fills the corresponding `n_samples` samples in the output
@@ -101,7 +95,7 @@ void bw_osc_filt_process(bw_osc_filt instance, const float *x, float* y, int n_s
 /*! ...
  *    #### bw_osc_filt_set_enabled()
  *  ```>>> */
-void bw_osc_filt_set_enabled(bw_osc_filt instance, char value);
+void bw_osc_filt_set_enabled(bw_osc_filt *instance, char value);
 /*! <<<```
  *    Sets whether the filter is enabled (`value` non-`0`) or bypassed (`0`)
  *    for the given `instance`.
@@ -109,6 +103,19 @@ void bw_osc_filt_set_enabled(bw_osc_filt instance, char value);
  *    Default value: non-`0`.
  *  }}} */
 
+/* WARNING: the internal definition of this struct is not part of the public
+ * API. Its content may change at any time in future versions. Please, do not
+ * access its members directly. */
+struct _bw_osc_filt {
+	// Parameters
+	char	enabled;
+
+	// State
+	float	x_z1;
+	float	y_z1;
+};
+
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/include/bw_osc_pulse.h b/include/bw_osc_pulse.h
index bd8f087..74d0f6a 100644
--- a/include/bw_osc_pulse.h
+++ b/include/bw_osc_pulse.h
@@ -19,7 +19,7 @@
 
 /*!
  *  module_type {{{ dsp }}}
- *  version {{{ 0.1.0 }}}
+ *  version {{{ 0.2.0 }}}
  *  requires {{{ bw_config bw_common bw_inline_one_pole bw_math }}}
  *  description {{{
  *    Pulse oscillator waveshaper with variable pulse width (actually, duty
@@ -27,6 +27,11 @@
  *  }}}
  *  changelog {{{
  *    <ul>
+ *      <li>Version <strong>0.2.0</strong>:
+ *        <ul>
+ *          <li>Refactored API to avoid dynamic memory allocation.</li>
+ *        </ul>
+ *      </li>
  *      <li>Version <strong>0.1.0</strong>:
  *        <ul>
  *          <li>First release.</li>
@@ -46,34 +51,23 @@ extern "C" {
 /*! api {{{
  *    #### bw_osc_pulse
  *  ```>>> */
-typedef struct _bw_osc_pulse *bw_osc_pulse;
+typedef struct _bw_osc_pulse bw_osc_pulse;
 /*! <<<```
- *    Instance handle.
+ *    Instance object.
  *  >>> */
 
 /*! ...
- *    #### bw_osc_pulse_new()
+ *    #### bw_osc_pulse_init()
  *  ```>>> */
-bw_osc_pulse bw_osc_pulse_new();
+void bw_osc_pulse_init(bw_osc_pulse *instance);
 /*! <<<```
- *    Creates a new instance.
- *
- *    Returns the newly-created instance handle or `NULL` if there was not
- *    enough memory.
- *  >>> */
-
-/*! ...
- *    #### bw_osc_pulse_free()
- *  ```>>> */
-void bw_osc_pulse_free(bw_osc_pulse instance);
-/*! <<<```
- *    Destroys an `instance`.
+ *    Initializes the `instance` object.
  *  >>> */
 
 /*! ...
  *    #### bw_osc_pulse_set_sample_rate()
  *  ```>>> */
-void bw_osc_pulse_set_sample_rate(bw_osc_pulse instance, float sample_rate);
+void bw_osc_pulse_set_sample_rate(bw_osc_pulse *instance, float sample_rate);
 /*! <<<```
  *    Sets the `sample_rate` (Hz) value for the given `instance`.
  *  >>> */
@@ -81,7 +75,7 @@ void bw_osc_pulse_set_sample_rate(bw_osc_pulse instance, float sample_rate);
 /*! ...
  *    #### bw_osc_pulse_reset()
  *  ```>>> */
-void bw_osc_pulse_reset(bw_osc_pulse instance);
+void bw_osc_pulse_reset(bw_osc_pulse *instance);
 /*! <<<```
  *    Resets the given `instance` to its initial state.
  *  >>> */
@@ -89,7 +83,7 @@ void bw_osc_pulse_reset(bw_osc_pulse instance);
 /*! ...
  *    #### bw_osc_pulse_process()
  *  ```>>> */
-void bw_osc_pulse_process(bw_osc_pulse instance, const float *x, const float *x_phase_inc, float* y, int n_samples);
+void bw_osc_pulse_process(bw_osc_pulse *instance, const float *x, const float *x_phase_inc, float* y, int n_samples);
 /*! <<<```
  *    Lets the given `instance` process `n_samples` samples from the input
  *    buffer `x` containing the normalized phase signal and fills the
@@ -102,7 +96,7 @@ void bw_osc_pulse_process(bw_osc_pulse instance, const float *x, const float *x_
 /*! ...
  *    #### bw_osc_pulse_set_antialiasing()
  *  ```>>> */
-void bw_osc_pulse_set_antialiasing(bw_osc_pulse instance, char value);
+void bw_osc_pulse_set_antialiasing(bw_osc_pulse *instance, char value);
 /*! <<<```
  *    Sets whether the antialiasing is on (`value` non-`0`) or off (`0`) for the
  *    given `instance`.
@@ -113,7 +107,7 @@ void bw_osc_pulse_set_antialiasing(bw_osc_pulse instance, char value);
 /*! ...
  *    #### bw_osc_pulse_set_pulse_width()
  *  ```>>> */
-void bw_osc_pulse_set_pulse_width(bw_osc_pulse instance, float value);
+void bw_osc_pulse_set_pulse_width(bw_osc_pulse *instance, float value);
 /*! <<<```
  *    Sets the pulse width (actually, the duty cycle) to `value` (range
  *    [`0.f`, `1.f`]) for the given `instance`.
@@ -121,6 +115,22 @@ void bw_osc_pulse_set_pulse_width(bw_osc_pulse instance, float value);
  *    Default value: `0.5f`.
  *  }}} */
 
+/* WARNING: the internal definition of this struct is not part of the public
+ * API. Its content may change at any time in future versions. Please, do not
+ * access its members directly. */
+struct _bw_osc_pulse {
+	// Coefficients
+	float	smooth_mA1;
+
+	// Parameters
+	char	first_run;
+	char	antialiasing;
+	float	pulse_width;
+
+	// State
+	float	pw_z1;
+};
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/include/bw_osc_saw.h b/include/bw_osc_saw.h
index 32989c6..ebf6996 100644
--- a/include/bw_osc_saw.h
+++ b/include/bw_osc_saw.h
@@ -19,13 +19,18 @@
 
 /*!
  *  module_type {{{ dsp }}}
- *  version {{{ 0.1.0 }}}
+ *  version {{{ 0.2.0 }}}
  *  requires {{{ bw_config bw_common bw_math }}}
  *  description {{{
  *    Sawtooth oscillator waveshaper with PolyBLEP antialiasing.
  *  }}}
  *  changelog {{{
  *    <ul>
+ *      <li>Version <strong>0.2.0</strong>:
+ *        <ul>
+ *          <li>Refactored API to avoid dynamic memory allocation.</li>
+ *        </ul>
+ *      </li>
  *      <li>Version <strong>0.1.0</strong>:
  *        <ul>
  *          <li>First release.</li>
@@ -45,28 +50,17 @@ extern "C" {
 /*! api {{{
  *    #### bw_osc_saw
  *  ```>>> */
-typedef struct _bw_osc_saw *bw_osc_saw;
+typedef struct _bw_osc_saw bw_osc_saw;
 /*! <<<```
- *    Instance handle.
+ *    Instance object.
  *  >>> */
 
 /*! ...
- *    #### bw_osc_saw_new()
+ *    #### bw_osc_saw_init()
  *  ```>>> */
-bw_osc_saw bw_osc_saw_new();
+void bw_osc_saw_init(bw_osc_saw *instance);
 /*! <<<```
- *    Creates a new instance.
- *
- *    Returns the newly-created instance handle or `NULL` if there was not
- *    enough memory.
- *  >>> */
-
-/*! ...
- *    #### bw_osc_saw_free()
- *  ```>>> */
-void bw_osc_saw_free(bw_osc_saw instance);
-/*! <<<```
- *    Destroys an `instance`.
+ *    Initializes the `instance` object.
  *  >>> */
 
 /*! ...
@@ -78,7 +72,7 @@ void bw_osc_saw_free(bw_osc_saw instance);
 /*! ...
  *    #### bw_osc_saw_process()
  *  ```>>> */
-void bw_osc_saw_process(bw_osc_saw instance, const float *x, const float *x_phase_inc, float* y, int n_samples);
+void bw_osc_saw_process(bw_osc_saw *instance, const float *x, const float *x_phase_inc, float* y, int n_samples);
 /*! <<<```
  *    Lets the given `instance` process `n_samples` samples from the input
  *    buffer `x` containing the normalized phase signal and fills the
@@ -88,7 +82,7 @@ void bw_osc_saw_process(bw_osc_saw instance, const float *x, const float *x_phas
 /*! ...
  *    #### bw_osc_saw_set_antialiasing()
  *  ```>>> */
-void bw_osc_saw_set_antialiasing(bw_osc_saw instance, char value);
+void bw_osc_saw_set_antialiasing(bw_osc_saw *instance, char value);
 /*! <<<```
  *    Sets whether the antialiasing is on (`value` non-`0`) or off (`0`) for the
  *    given `instance`.
@@ -96,6 +90,14 @@ void bw_osc_saw_set_antialiasing(bw_osc_saw instance, char value);
  *    Default value: `0`.
  *  }}} */
 
+/* WARNING: the internal definition of this struct is not part of the public
+ * API. Its content may change at any time in future versions. Please, do not
+ * access its members directly. */
+struct _bw_osc_saw {
+	// Parameters
+	char	antialiasing;
+};
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/include/bw_osc_tri.h b/include/bw_osc_tri.h
index 231388a..8d58e26 100644
--- a/include/bw_osc_tri.h
+++ b/include/bw_osc_tri.h
@@ -19,7 +19,7 @@
 
 /*!
  *  module_type {{{ dsp }}}
- *  version {{{ 0.1.0 }}}
+ *  version {{{ 0.2.0 }}}
  *  requires {{{ bw_config bw_common bw_inline_one_pole bw_math }}}
  *  description {{{
  *    Triangle oscillator waveshaper with variable slope (increasing time over
@@ -27,6 +27,11 @@
  *  }}}
  *  changelog {{{
  *    <ul>
+ *      <li>Version <strong>0.2.0</strong>:
+ *        <ul>
+ *          <li>Refactored API to avoid dynamic memory allocation.</li>
+ *        </ul>
+ *      </li>
  *      <li>Version <strong>0.1.0</strong>:
  *        <ul>
  *          <li>First release.</li>
@@ -46,34 +51,23 @@ extern "C" {
 /*! api {{{
  *    #### bw_osc_tri
  *  ```>>> */
-typedef struct _bw_osc_tri *bw_osc_tri;
+typedef struct _bw_osc_tri bw_osc_tri;
 /*! <<<```
- *    Instance handle.
+ *    Instance object.
  *  >>> */
 
 /*! ...
- *    #### bw_osc_tri_new()
+ *    #### bw_osc_tri_init()
  *  ```>>> */
-bw_osc_tri bw_osc_tri_new();
+void bw_osc_tri_init(bw_osc_tri *instance);
 /*! <<<```
- *    Creates a new instance.
- *
- *    Returns the newly-created instance handle or `NULL` if there was not
- *    enough memory.
- *  >>> */
-
-/*! ...
- *    #### bw_osc_tri_free()
- *  ```>>> */
-void bw_osc_tri_free(bw_osc_tri instance);
-/*! <<<```
- *    Destroys an `instance`.
+ *    Initializes the `instance` object.
  *  >>> */
 
 /*! ...
  *    #### bw_osc_tri_set_sample_rate()
  *  ```>>> */
-void bw_osc_tri_set_sample_rate(bw_osc_tri instance, float sample_rate);
+void bw_osc_tri_set_sample_rate(bw_osc_tri *instance, float sample_rate);
 /*! <<<```
  *    Sets the `sample_rate` (Hz) value for the given `instance`.
  *  >>> */
@@ -81,7 +75,7 @@ void bw_osc_tri_set_sample_rate(bw_osc_tri instance, float sample_rate);
 /*! ...
  *    #### bw_osc_tri_reset()
  *  ```>>> */
-void bw_osc_tri_reset(bw_osc_tri instance);
+void bw_osc_tri_reset(bw_osc_tri *instance);
 /*! <<<```
  *    Resets the given `instance` to its initial state.
  *  >>> */
@@ -89,7 +83,7 @@ void bw_osc_tri_reset(bw_osc_tri instance);
 /*! ...
  *    #### bw_osc_tri_process()
  *  ```>>> */
-void bw_osc_tri_process(bw_osc_tri instance, const float *x, const float *x_phase_inc, float* y, int n_samples);
+void bw_osc_tri_process(bw_osc_tri *instance, const float *x, const float *x_phase_inc, float* y, int n_samples);
 /*! <<<```
  *    Lets the given `instance` process `n_samples` samples from the input
  *    buffer `x` containing the normalized phase signal and fills the
@@ -102,7 +96,7 @@ void bw_osc_tri_process(bw_osc_tri instance, const float *x, const float *x_phas
 /*! ...
  *    #### bw_osc_tri_set_antialiasing()
  *  ```>>> */
-void bw_osc_tri_set_antialiasing(bw_osc_tri instance, char value);
+void bw_osc_tri_set_antialiasing(bw_osc_tri *instance, char value);
 /*! <<<```
  *    Sets whether the antialiasing is on (`value` non-`0`) or off (`0`) for the
  *    given `instance`.
@@ -113,7 +107,7 @@ void bw_osc_tri_set_antialiasing(bw_osc_tri instance, char value);
 /*! ...
  *    #### bw_osc_tri_set_slope()
  *  ```>>> */
-void bw_osc_tri_set_slope(bw_osc_tri instance, float value);
+void bw_osc_tri_set_slope(bw_osc_tri *instance, float value);
 /*! <<<```
  *    Sets the slope (increasing time over period) to `value` (range [`0.f`,
  *    `1.f`]) for the given `instance`.
@@ -121,6 +115,22 @@ void bw_osc_tri_set_slope(bw_osc_tri instance, float value);
  *    Default value: `0.5f`.
  *  }}} */
 
+/* WARNING: the internal definition of this struct is not part of the public
+ * API. Its content may change at any time in future versions. Please, do not
+ * access its members directly. */
+struct _bw_osc_tri {
+	// Coefficients
+	float	smooth_mA1;
+
+	// Parameters
+	char	first_run;
+	char	antialiasing;
+	float	slope;
+
+	// State
+	float	slope_z1;
+};
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/include/bw_phase_gen.h b/include/bw_phase_gen.h
index 3a986db..35bc45e 100644
--- a/include/bw_phase_gen.h
+++ b/include/bw_phase_gen.h
@@ -19,7 +19,7 @@
 
 /*!
  *  module_type {{{ dsp }}}
- *  version {{{ 0.1.0 }}}
+ *  version {{{ 0.2.0 }}}
  *  requires {{{ bw_config bw_common bw_math }}}
  *  description {{{
  *    Phase generator with portamento and exponential frequency modulation.
@@ -28,6 +28,11 @@
  *  }}}
  *  changelog {{{
  *    <ul>
+ *      <li>Version <strong>0.2.0</strong>:
+ *        <ul>
+ *          <li>Refactored API to avoid dynamic memory allocation.</li>
+ *        </ul>
+ *      </li>
  *      <li>Version <strong>0.1.0</strong>:
  *        <ul>
  *          <li>First release.</li>
@@ -47,34 +52,23 @@ extern "C" {
 /*! api {{{
  *    #### bw_phase_gen
  *  ```>>> */
-typedef struct _bw_phase_gen *bw_phase_gen;
+typedef struct _bw_phase_gen bw_phase_gen;
 /*! <<<```
- *    Instance handle.
+ *    Instance object.
  *  >>> */
 
 /*! ...
- *    #### bw_phase_gen_new()
+ *    #### bw_phase_gen_init()
  *  ```>>> */
-bw_phase_gen bw_phase_gen_new();
+void bw_phase_gen_init(bw_phase_gen *instance);
 /*! <<<```
- *    Creates a new instance.
- *
- *    Returns the newly-created instance handle or `NULL` if there was not
- *    enough memory.
- *  >>> */
-
-/*! ...
- *    #### bw_phase_gen_free()
- *  ```>>> */
-void bw_phase_gen_free(bw_phase_gen instance);
-/*! <<<```
- *    Destroys an `instance`.
+ *    Initializes the `instance` object.
  *  >>> */
 
 /*! ...
  *    #### bw_phase_gen_set_sample_rate()
  *  ```>>> */
-void bw_phase_gen_set_sample_rate(bw_phase_gen instance, float sample_rate);
+void bw_phase_gen_set_sample_rate(bw_phase_gen *instance, float sample_rate);
 /*! <<<```
  *    Sets the `sample_rate` (Hz) value for the given `instance`.
  *  >>> */
@@ -82,7 +76,7 @@ void bw_phase_gen_set_sample_rate(bw_phase_gen instance, float sample_rate);
 /*! ...
  *    #### bw_phase_gen_reset()
  *  ```>>> */
-void bw_phase_gen_reset(bw_phase_gen instance);
+void bw_phase_gen_reset(bw_phase_gen *instance);
 /*! <<<```
  *    Resets the given `instance` to its initial state.
  *  >>> */
@@ -90,7 +84,7 @@ void bw_phase_gen_reset(bw_phase_gen instance);
 /*! ...
  *    #### bw_phase_gen_process()
  *  ```>>> */
-void bw_phase_gen_process(bw_phase_gen instance, const float *x_mod, float* y, float *y_phase_inc, int n_samples);
+void bw_phase_gen_process(bw_phase_gen *instance, const float *x_mod, float* y, float *y_phase_inc, int n_samples);
 /*! <<<```
  *    Lets the given `instance` generate `n_samples` samples and puts them in
  *    the output buffer `y`.
@@ -104,7 +98,7 @@ void bw_phase_gen_process(bw_phase_gen instance, const float *x_mod, float* y, f
 /*! ...
  *    #### bw_phase_gen_set_frequency()
  *  ```>>> */
-void bw_phase_gen_set_frequency(bw_phase_gen instance, float value);
+void bw_phase_gen_set_frequency(bw_phase_gen *instance, float value);
 /*! <<<```
  *    Sets the base frequency to `value` (Hz) for the given `instance`.
  *    
@@ -114,13 +108,34 @@ void bw_phase_gen_set_frequency(bw_phase_gen instance, float value);
 /*! ...
  *    #### bw_phase_gen_set_portamento_tau()
  *  ```>>> */
-void bw_phase_gen_set_portamento_tau(bw_phase_gen instance, float value);
+void bw_phase_gen_set_portamento_tau(bw_phase_gen *instance, float value);
 /*! <<<```
  *    Sets the portamento time constant `value` (s) for the given `instance`.
  *
  *    Default value: `0.f`.
  *  }}} */
 
+/* WARNING: the internal definition of this struct is not part of the public
+ * API. Its content may change at any time in future versions. Please, do not
+ * access its members directly. */
+struct _bw_phase_gen {
+	// Coefficients
+	float		T;
+
+	float		portamento_target;
+	float		portamento_mA1;
+
+	// Parameters
+	float		frequency;
+	float		portamento_tau;
+	int		param_changed;
+
+	// State
+	char		first_run;
+	float		phase;
+	float		portamento_z1;
+};
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/include/bw_slew_lim.h b/include/bw_slew_lim.h
index d2b348b..3edca45 100644
--- a/include/bw_slew_lim.h
+++ b/include/bw_slew_lim.h
@@ -19,13 +19,18 @@
 
 /*!
  *  module_type {{{ dsp }}}
- *  version {{{ 0.1.0 }}}
+ *  version {{{ 0.2.0 }}}
  *  requires {{{ bw_config bw_common bw_math }}}
  *  description {{{
  *    Slew-rate limiter with separate maximum increasing and decreasing rates.
  *  }}}
  *  changelog {{{
  *    <ul>
+ *      <li>Version <strong>0.2.0</strong>:
+ *        <ul>
+ *          <li>Refactored API to avoid dynamic memory allocation.</li>
+ *        </ul>
+ *      </li>
  *      <li>Version <strong>0.1.0</strong>:
  *        <ul>
  *          <li>First release.</li>
@@ -45,34 +50,23 @@ extern "C" {
 /*! api {{{
  *    #### bw_slew_lim
  *  ```>>> */
-typedef struct _bw_slew_lim *bw_slew_lim;
+typedef struct _bw_slew_lim bw_slew_lim;
 /*! <<<```
- *    Instance handle.
+ *    Instance object.
  *  >>> */
  
 /*! ...
- *    #### bw_slew_lim_new()
+ *    #### bw_slew_lim_init()
  *  ```>>> */
-bw_slew_lim bw_slew_lim_new();
+void bw_slew_lim_new(bw_slew_lim *instance);
 /*! <<<```
- *    Creates a new instance.
- *
- *    Returns the newly-created instance handle or `NULL` if there was not
- *    enough memory.
- *  >>> */
-
-/*! ...
- *    #### bw_slew_lim_free()
- *  ```>>> */
-void bw_slew_lim_free(bw_slew_lim instance);
-/*! <<<```
- *    Destroys an `instance`.
+ *    Initializes the `instance` object.
  *  >>> */
 
 /*! ...
  *    #### bw_slew_lim_set_sample_rate()
  *  ```>>> */
-void bw_slew_lim_set_sample_rate(bw_slew_lim instance, float sample_rate);
+void bw_slew_lim_set_sample_rate(bw_slew_lim *instance, float sample_rate);
 /*! <<<```
  *    Sets the `sample_rate` (Hz) value for the given `instance`.
  *  >>> */
@@ -80,7 +74,7 @@ void bw_slew_lim_set_sample_rate(bw_slew_lim instance, float sample_rate);
 /*! ...
  *    #### bw_slew_lim_reset()
  *  ```>>> */
-void bw_slew_lim_reset(bw_slew_lim instance);
+void bw_slew_lim_reset(bw_slew_lim *instance);
 /*! <<<```
  *    Resets the given `instance` to its initial state.
  *  >>> */
@@ -88,7 +82,7 @@ void bw_slew_lim_reset(bw_slew_lim instance);
 /*! ...
  *    #### bw_slew_lim_process()
  *  ```>>> */
-void bw_slew_lim_process(bw_slew_lim instance, const float* x, float* y, int n_samples);
+void bw_slew_lim_process(bw_slew_lim *instance, const float* x, float* y, int n_samples);
 /*! <<<```
  *    Lets the given `instance` process `n_samples` samples from the input
  *    buffer `x` and fills the corresponding `n_samples` samples in the output
@@ -98,7 +92,7 @@ void bw_slew_lim_process(bw_slew_lim instance, const float* x, float* y, int n_s
 /*! ...
  *    #### bw_slew_lim_set_init_val()
  *  ```>>> */
-void bw_slew_lim_set_init_val(bw_slew_lim instance, float value);
+void bw_slew_lim_set_init_val(bw_slew_lim *instance, float value);
 /*! <<<```
  *    Sets the initial/quiescent `value` for the given `instance`.
  *
@@ -112,7 +106,7 @@ void bw_slew_lim_set_init_val(bw_slew_lim instance, float value);
 /*! ...
  *    #### bw_slew_lim_set_max_rate()
  *  ```>>> */
-void bw_slew_lim_set_max_rate(bw_slew_lim instance, float value);
+void bw_slew_lim_set_max_rate(bw_slew_lim *instance, float value);
 /*! <<<```
  *    Sets both the maximum increasing and decreasing variation rate to the
  *    given `value` (1/s) for the given `instance`.
@@ -129,7 +123,7 @@ void bw_slew_lim_set_max_rate(bw_slew_lim instance, float value);
 /*! ...
  *    #### bw_slew_lim_set_max_inc_rate()
  *  ```>>> */
-void bw_slew_lim_set_max_inc_rate(bw_slew_lim instance, float value);
+void bw_slew_lim_set_max_inc_rate(bw_slew_lim *instance, float value);
 /*! <<<```
  *    Sets the maximum increasing variation rate to the given `value` (1/s) for
  *    the given `instance`.
@@ -143,7 +137,7 @@ void bw_slew_lim_set_max_inc_rate(bw_slew_lim instance, float value);
 /*! ...
  *    #### bw_slew_lim_set_max_inc_rate()
  *  ```>>> */
-void bw_slew_lim_set_max_dec_rate(bw_slew_lim instance, float value);
+void bw_slew_lim_set_max_dec_rate(bw_slew_lim *instance, float value);
 /*! <<<```
  *    Sets the maximum decreasing variation rate to the given `value` (1/s) for
  *    the given `instance`.
@@ -154,6 +148,23 @@ void bw_slew_lim_set_max_dec_rate(bw_slew_lim instance, float value);
  *    Default value: `INFINITY`.
  *  }}} */
 
+/* WARNING: the internal definition of this struct is not part of the public
+ * API. Its content may change at any time in future versions. Please, do not
+ * access its members directly. */
+struct _bw_slew_lim {
+	// Coefficients
+	float	T;
+
+	// Parameters
+	float	init_val;
+	float	max_inc_rate;
+	float	max_dec_rate;
+
+	// State
+	char	first_run;
+	float	y_z1;
+};
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/include/bw_svf.h b/include/bw_svf.h
index d3bc900..466566b 100644
--- a/include/bw_svf.h
+++ b/include/bw_svf.h
@@ -19,7 +19,7 @@
 
 /*!
  *  module_type {{{ dsp }}}
- *  version {{{ 0.1.0 }}}
+ *  version {{{ 0.2.0 }}}
  *  requires {{{ bw_config bw_common bw_inline_one_pole bw_math }}}
  *  description {{{
  *    State variable filter (2nd order, 12 dB/oct) model with separated lowpass,
@@ -27,6 +27,11 @@
  *  }}}
  *  changelog {{{
  *    <ul>
+ *      <li>Version <strong>0.2.0</strong>:
+ *        <ul>
+ *          <li>Refactored API to avoid dynamic memory allocation.</li>
+ *        </ul>
+ *      </li>
  *      <li>Version <strong>0.1.0</strong>:
  *        <ul>
  *          <li>First release.</li>
@@ -46,34 +51,23 @@ extern "C" {
 /*! api {{{
  *    #### bw_svf
  *  ```>>> */
-typedef struct _bw_svf *bw_svf;
+typedef struct _bw_svf bw_svf;
 /*! <<<```
- *    Instance handle.
+ *    Instance object.
  *  >>> */
 
 /*! ...
- *    #### bw_svf_new()
+ *    #### bw_svf_init()
  *  ```>>> */
-bw_svf bw_svf_new();
+void bw_svf_init(bw_svf *instance);
 /*! <<<```
- *    Creates a new instance.
- *
- *    Returns the newly-created instance handle or `NULL` if there was not
- *    enough memory.
- *  >>> */
-
-/*! ...
- *    #### bw_svf_free()
- *  ```>>> */
-void bw_svf_free(bw_svf instance);
-/*! <<<```
- *    Destroys an `instance`.
+ *    Initializes the `instance` object.
  *  >>> */
 
 /*! ...
  *    #### bw_svf_set_sample_rate()
  *  ```>>> */
-void bw_svf_set_sample_rate(bw_svf instance, float sample_rate);
+void bw_svf_set_sample_rate(bw_svf *instance, float sample_rate);
 /*! <<<```
  *    Sets the `sample_rate` (Hz) value for the given `instance`.
  *  >>> */
@@ -81,7 +75,7 @@ void bw_svf_set_sample_rate(bw_svf instance, float sample_rate);
 /*! ...
  *    #### bw_svf_reset()
  *  ```>>> */
-void bw_svf_reset(bw_svf instance);
+void bw_svf_reset(bw_svf *instance);
 /*! <<<```
  *    Resets the given `instance` to its initial state.
  *  >>> */
@@ -89,7 +83,7 @@ void bw_svf_reset(bw_svf instance);
 /*! ...
  *    #### bw_svf_process()
  *  ```>>> */
-void bw_svf_process(bw_svf instance, const float *x, float* y_lp, float *y_bp, float *y_hp, int n_samples);
+void bw_svf_process(bw_svf *instance, const float *x, float* y_lp, float *y_bp, float *y_hp, int n_samples);
 /*! <<<```
  *    Lets the given `instance` process `n_samples` samples from the input
  *    buffer `x` and fills the corresponding `n_samples` samples in the output
@@ -100,7 +94,7 @@ void bw_svf_process(bw_svf instance, const float *x, float* y_lp, float *y_bp, f
 /*! ...
  *    #### bw_svf_set_cutoff()
  *  ```>>> */
-void bw_svf_set_cutoff(bw_svf instance, float value);
+void bw_svf_set_cutoff(bw_svf *instance, float value);
 /*! <<<```
  *    Sets the cutoff frequency to the given `value` (Hz) for the given
  *    `instance`.
@@ -111,7 +105,7 @@ void bw_svf_set_cutoff(bw_svf instance, float value);
 /*! ...
  *    #### bw_svf_set_Q()
  *  ```>>> */
-void bw_svf_set_Q(bw_svf instance, float value);
+void bw_svf_set_Q(bw_svf *instance, float value);
 /*! <<<```
  *    Sets the quality factor to the given `value` (Hz) for the given
  *    `instance`.
@@ -119,6 +113,34 @@ void bw_svf_set_Q(bw_svf instance, float value);
  *    Default value: `0.5f`.
  *  }}} */
 
+/* WARNING: the internal definition of this struct is not part of the public
+ * API. Its content may change at any time in future versions. Please, do not
+ * access its members directly. */
+struct _bw_svf {
+	// Coefficients
+	float	t_k;
+	float	smooth_mA1;
+
+	float	t;
+	float	k;
+	float	hp_hp_z1;
+	float	hp_bp_z1;
+	float	hp_x;
+
+	// Parameters
+	float	cutoff;
+	float	Q;
+
+	float	cutoff_cur;
+	float	Q_cur;
+
+	// State
+	char	first_run;
+	float	hp_z1;
+	float	lp_z1;
+	float	bp_z1;
+};
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/include/bw_vol.h b/include/bw_vol.h
index 9b1a85f..f6cb4ad 100644
--- a/include/bw_vol.h
+++ b/include/bw_vol.h
@@ -19,13 +19,18 @@
 
 /*!
  *  module_type {{{ dsp }}}
- *  version {{{ 0.1.0 }}}
+ *  version {{{ 0.2.0 }}}
  *  requires {{{ bw_config bw_common bw_inline_slew_lim bw_math }}}
  *  description {{{
  *    Volume control for an arbitrary number of channels.
  *  }}}
  *  changelog {{{
  *    <ul>
+ *      <li>Version <strong>0.2.0</strong>:
+ *        <ul>
+ *          <li>Refactored API to avoid dynamic memory allocation.</li>
+ *        </ul>
+ *      </li>
  *      <li>Version <strong>0.1.0</strong>:
  *        <ul>
  *          <li>First release.</li>
@@ -45,34 +50,23 @@ extern "C" {
 /*! api {{{
  *    #### bw_vol
  *  ```>>> */
-typedef struct _bw_vol *bw_vol;
+typedef struct _bw_vol bw_vol;
 /*! <<<```
- *    Instance handle.
+ *    Instance object.
  *  >>> */
 
 /*! ...
- *    #### bw_vol_new()
+ *    #### bw_vol_init()
  *  ```>>> */
-bw_vol bw_vol_new();
+void bw_vol_init(bw_vol *instance);
 /*! <<<```
- *    Creates a new instance.
- *
- *    Returns the newly-created instance handle or `NULL` if there was not
- *    enough memory.
- *  >>> */
-
-/*! ...
- *    #### bw_vol_free()
- *  ```>>> */
-void bw_vol_free(bw_vol instance);
-/*! <<<```
- *    Destroys an `instance`.
+ *    Initializes the `instance` object.
  *  >>> */
 
 /*! ...
  *    #### bw_vol_set_sample_rate()
  *  ```>>> */
-void bw_vol_set_sample_rate(bw_vol instance, float sample_rate);
+void bw_vol_set_sample_rate(bw_vol *instance, float sample_rate);
 /*! <<<```
  *    Sets the `sample_rate` (Hz) value for the given `instance`.
  *  >>> */
@@ -80,7 +74,7 @@ void bw_vol_set_sample_rate(bw_vol instance, float sample_rate);
 /*! ...
  *    #### bw_vol_reset()
  *  ```>>> */
-void bw_vol_reset(bw_vol instance);
+void bw_vol_reset(bw_vol *instance);
 /*! <<<```
  *    Resets the given `instance` to its initial state.
  *  >>> */
@@ -88,7 +82,7 @@ void bw_vol_reset(bw_vol instance);
 /*! ...
  *    #### bw_vol_process()
  *  ```>>> */
-void bw_vol_process(bw_vol instance, const float **x, float **y, int n_channels, int n_samples);
+void bw_vol_process(bw_vol *instance, const float **x, float **y, int n_channels, int n_samples);
 /*! <<<```
  *    Lets the given `instance` process `n_samples` samples from each of the
  *    `n_channels` input buffers and fills the corresponding `n_samples` samples
@@ -101,7 +95,7 @@ void bw_vol_process(bw_vol instance, const float **x, float **y, int n_channels,
 /*! ...
  *    #### bw_vol_set_volume()
  *  ```>>> */
-void bw_vol_set_volume(bw_vol instance, float value);
+void bw_vol_set_volume(bw_vol *instance, float value);
 /*! <<<```
  *    Sets the volume parameter to the given `value` (range [`0.f`, `1.f`]) for
  *    the given `instance`.
@@ -112,6 +106,29 @@ void bw_vol_set_volume(bw_vol instance, float value);
  *    Default value: `1.f`.
  *  }}} */
 
+/* WARNING: this definition is not part of the public API. Please, do not use
+ * it. */
+#define _BW_VOL_BUFFER_SIZE	32
+
+/* WARNING: the internal definition of this struct is not part of the public
+ * API. Its content may change at any time in future versions. Please, do not
+ * access its members directly. */
+struct _bw_vol {
+	// Coefficients
+	float	max_var;
+
+	// Parameters
+	float	volume;
+
+	float	volume_cur;
+
+	// State
+	char	first_run;
+
+	// Buffers
+	float	buf[_BW_VOL_BUFFER_SIZE];
+};
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/bw_env_follow.c b/src/bw_env_follow.c
index a957ff8..0b22797 100644
--- a/src/bw_env_follow.c
+++ b/src/bw_env_follow.c
@@ -21,44 +21,24 @@
 
 #include <bw_math.h>
 
-struct _bw_env_follow {
-	// Sub-components
-	bw_one_pole	one_pole;
-};
-
-bw_env_follow bw_env_follow_new() {
-	bw_env_follow instance = (bw_env_follow)BW_MALLOC(sizeof(struct _bw_env_follow));
-	if (instance == NULL)
-		return NULL;
-
-	instance->one_pole = bw_one_pole_new();
-	if (instance->one_pole == NULL) {
-		BW_FREE(instance);
-		return NULL;
-	}
-
-	return instance;
+void bw_env_follow_init(bw_env_follow *instance) {
+	bw_one_pole_init(&instance->one_pole);
 }
 
-void bw_env_follow_free(bw_env_follow instance) {
-	bw_one_pole_free(instance->one_pole);
-	BW_FREE(instance);
+void bw_env_follow_set_sample_rate(bw_env_follow *instance, float sample_rate) {
+	bw_one_pole_set_sample_rate(&instance->one_pole, sample_rate);
 }
 
-void bw_env_follow_set_sample_rate(bw_env_follow instance, float sample_rate) {
-	bw_one_pole_set_sample_rate(instance->one_pole, sample_rate);
+void bw_env_follow_reset(bw_env_follow *instance) {
+	bw_one_pole_reset(&instance->one_pole);
 }
 
-void bw_env_follow_reset(bw_env_follow instance) {
-	bw_one_pole_reset(instance->one_pole);
-}
-
-void bw_env_follow_process(bw_env_follow instance, const float *x, float *y, int n_samples) {
+void bw_env_follow_process(bw_env_follow *instance, const float *x, float *y, int n_samples) {
 	for (int i = 0; i < n_samples; i++)
 		y[i] = bw_absf(x[i]);
-	bw_one_pole_process(instance->one_pole, y, y, n_samples);
+	bw_one_pole_process(&instance->one_pole, y, y, n_samples);
 }
 
-bw_one_pole bw_env_follow_get_one_pole(bw_env_follow instance) {
-	return instance->one_pole;
+bw_one_pole *bw_env_follow_get_one_pole(bw_env_follow *instance) {
+	return &instance->one_pole;
 }
diff --git a/src/bw_env_gen.c b/src/bw_env_gen.c
index aed525e..9eef6d2 100644
--- a/src/bw_env_gen.c
+++ b/src/bw_env_gen.c
@@ -22,61 +22,20 @@
 #include <bw_math.h>
 #include <bw_inline_one_pole.h>
 
-typedef enum {
-	state_off,
-	state_attack,
-	state_decay,
-	state_sustain,
-	state_release
-} state_t;
-
-struct _bw_env_gen {
-	// Coefficients
-	float	T;
-	float	smooth_mA1;
-
-	float	attack_inc;
-	float	decay_inc;
-	float	release_inc;
-
-	// Parameters
-	char	gate;
-	float	attack;
-	float	decay;
-	float	sustain;
-	float	release;
-	int	param_changed;
-
-	// State
-	char	first_run;
-	state_t	state;
-	float	y_z1;
-};
-
-bw_env_gen bw_env_gen_new() {
-	bw_env_gen instance = (bw_env_gen)BW_MALLOC(sizeof(struct _bw_env_gen));
-	if (instance == NULL)
-		return NULL;
-
+void bw_env_gen_init(bw_env_gen *instance) {
 	instance->gate = 0;
 	instance->attack = 0.f;
 	instance->decay = 0.f;
 	instance->sustain = 1.f;
 	instance->release = 0.f;
-
-	return instance;
 }
 
-void bw_env_gen_free(bw_env_gen instance) {
-	BW_FREE(instance);
-}
-
-void bw_env_gen_set_sample_rate(bw_env_gen instance, float sample_rate) {
+void bw_env_gen_set_sample_rate(bw_env_gen *instance, float sample_rate) {
 	instance->T = 1.f / sample_rate;
 	instance->smooth_mA1 = bw_inline_one_pole_get_mA1(sample_rate, 0.05f);
 }
 
-void bw_env_gen_reset(bw_env_gen instance) {
+void bw_env_gen_reset(bw_env_gen *instance) {
 	instance->first_run = 1;
 	instance->param_changed = ~0;
 }
@@ -86,7 +45,7 @@ void bw_env_gen_reset(bw_env_gen instance) {
 #define PARAM_SUSTAIN	(1<<2)
 #define PARAM_RELEASE	(1<<3)
 
-void bw_env_gen_process(bw_env_gen instance, float* y, int n_samples) {
+void bw_env_gen_process(bw_env_gen *instance, float* y, int n_samples) {
 	if (instance->param_changed) {
 		// 1 ns considered instantaneous
 		if (instance->param_changed & PARAM_ATTACK)
@@ -98,47 +57,47 @@ void bw_env_gen_process(bw_env_gen instance, float* y, int n_samples) {
 	}
 
 	if (instance->first_run) {
-		instance->state = state_off;
+		instance->state = _bw_env_gen_state_off;
 		instance->y_z1 = 0.f;
 		instance->first_run = 0;
 	}
 
 	if (instance->gate) {
-		if (instance->state == state_off || instance->state == state_release)
-			instance->state = state_attack;
+		if (instance->state == _bw_env_gen_state_off || instance->state == _bw_env_gen_state_release)
+			instance->state = _bw_env_gen_state_attack;
 	} else {
-		if (instance->state != state_off)
-			instance->state = state_release;
+		if (instance->state != _bw_env_gen_state_off)
+			instance->state = _bw_env_gen_state_release;
 	}
 
 	for (int i = 0; i < n_samples; i++) {
 		float v;
 		switch (instance->state) {
-		case state_attack:
+		case _bw_env_gen_state_attack:
 			v = instance->y_z1 + instance->attack_inc;
 			if (v >= 1.f) {
 				v = 1.f;
-				instance->state = state_decay;
+				instance->state = _bw_env_gen_state_decay;
 			}
 			break;
-		case state_decay:
+		case _bw_env_gen_state_decay:
 			v = instance->y_z1 + instance->decay_inc;
 			if (v <= instance->sustain) {
 				v = instance->sustain;
-				instance->state = state_sustain;
+				instance->state = _bw_env_gen_state_sustain;
 			}
 			break;
-		case state_sustain:
+		case _bw_env_gen_state_sustain:
 			v = bw_inline_one_pole(instance->sustain, instance->y_z1, instance->smooth_mA1);
 			break;
-		case state_release:
+		case _bw_env_gen_state_release:
 			v = instance->y_z1 + instance->release_inc;
 			if (v <= 0.f) {
 				v = 0.f;
-				instance->state = state_off;
+				instance->state = _bw_env_gen_state_off;
 			}
 			break;
-		case state_off:
+		case _bw_env_gen_state_off:
 			v = 0.f;
 			break;
 		}
@@ -148,38 +107,38 @@ void bw_env_gen_process(bw_env_gen instance, float* y, int n_samples) {
 	}
 }
 
-void bw_env_gen_set_gate(bw_env_gen instance, char value) {
+void bw_env_gen_set_gate(bw_env_gen *instance, char value) {
 	instance->gate = value;
 }
 
-void bw_env_gen_set_attack(bw_env_gen instance, float value) {
+void bw_env_gen_set_attack(bw_env_gen *instance, float value) {
 	if (instance->attack != value) {
 		instance->attack = value;
 		instance->param_changed |= PARAM_ATTACK;
 	}
 }
 
-void bw_env_gen_set_decay(bw_env_gen instance, float value) {
+void bw_env_gen_set_decay(bw_env_gen *instance, float value) {
 	if (instance->decay != value) {
 		instance->decay = value;
 		instance->param_changed |= PARAM_DECAY;
 	}
 }
 
-void bw_env_gen_set_sustain(bw_env_gen instance, float value) {
+void bw_env_gen_set_sustain(bw_env_gen *instance, float value) {
 	if (instance->sustain != value) {
 		instance->sustain = value;
 		instance->param_changed |= PARAM_SUSTAIN;
 	}
 }
 
-void bw_env_gen_set_release(bw_env_gen instance, float value) {
+void bw_env_gen_set_release(bw_env_gen *instance, float value) {
 	if (instance->release != value) {
 		instance->release = value;
 		instance->param_changed |= PARAM_RELEASE;
 	}
 }
 
-char bw_env_gen_get_is_off(bw_env_gen instance) {
-	return instance->state == state_off;
+char bw_env_gen_get_is_off(bw_env_gen *instance) {
+	return instance->state == _bw_env_gen_state_off;
 }
diff --git a/src/bw_noise_gen.c b/src/bw_noise_gen.c
index 1937c24..6b13237 100644
--- a/src/bw_noise_gen.c
+++ b/src/bw_noise_gen.c
@@ -22,36 +22,16 @@
 #include <bw_rand.h>
 #include <bw_math.h>
 
-struct _bw_noise_gen {
-	// Coefficients
-	float		 scaling_k;
-
-	// Parameters
-	char		 sample_rate_scaling;
-
-	// State
-	uint64_t	*state;
-};
-
-bw_noise_gen bw_noise_gen_new(uint64_t *state) {
-	bw_noise_gen instance = (bw_noise_gen)BW_MALLOC(sizeof(struct _bw_noise_gen));
-	if (instance == NULL)
-		return NULL;
-
+void bw_noise_gen_init(bw_noise_gen *instance, uint64_t *state) {
 	instance->state = state;
 	instance->sample_rate_scaling = 0;
-	return instance;
 }
 
-void bw_noise_gen_free(bw_noise_gen instance) {
-	BW_FREE(instance);
-}
-
-void bw_noise_gen_set_sample_rate(bw_noise_gen instance, float sample_rate) {
+void bw_noise_gen_set_sample_rate(bw_noise_gen *instance, float sample_rate) {
 	instance->scaling_k = 0.004761904761904762f * bw_sqrtf_2(sample_rate);
 }
 
-void bw_noise_gen_process(bw_noise_gen instance, float* y, int n_samples) {
+void bw_noise_gen_process(bw_noise_gen *instance, float* y, int n_samples) {
 	for (int i = 0; i < n_samples; i++)
 		y[i] = bw_rand_f(instance->state);
 
@@ -60,6 +40,6 @@ void bw_noise_gen_process(bw_noise_gen instance, float* y, int n_samples) {
 			y[i] *= instance->scaling_k;
 }
 
-void bw_noise_gen_set_sample_rate_scaling(bw_noise_gen instance, char value) {
+void bw_noise_gen_set_sample_rate_scaling(bw_noise_gen *instance, char value) {
 	instance->sample_rate_scaling = value;
 }
diff --git a/src/bw_one_pole.c b/src/bw_one_pole.c
index c03b728..9b0d954 100644
--- a/src/bw_one_pole.c
+++ b/src/bw_one_pole.c
@@ -21,48 +21,18 @@
 
 #include <bw_math.h>
 
-struct _bw_one_pole {
-	// Coefficients
-	float			Ttm2pi;
-
-	float			mA1u;
-	float			mA1d;
-	float			st2;
-
-	// Parameters
-	float			init_val;
-	float			cutoff_up;
-	float			cutoff_down;
-	float			sticky_thresh;
-	bw_one_pole_sticky_mode sticky_mode;
-	int			param_changed;
-
-	// State
-	char	first_run;
-	float	x_z1;
-	float	y_z1;
-};
-
-bw_one_pole bw_one_pole_new() {
-	bw_one_pole instance = (bw_one_pole)BW_MALLOC(sizeof(struct _bw_one_pole));
-	if (instance != NULL) {
-		instance->init_val = 0.f;
-		instance->cutoff_up = INFINITY;
-		instance->cutoff_down = INFINITY;
-		instance->sticky_thresh = 0.f;
-	}
-	return instance;
+void bw_one_pole_init(bw_one_pole *instance) {
+	instance->init_val = 0.f;
+	instance->cutoff_up = INFINITY;
+	instance->cutoff_down = INFINITY;
+	instance->sticky_thresh = 0.f;
 }
 
-void bw_one_pole_free(bw_one_pole instance) {
-	BW_FREE(instance);
-}
-
-void bw_one_pole_set_sample_rate(bw_one_pole instance, float sample_rate) {
+void bw_one_pole_set_sample_rate(bw_one_pole *instance, float sample_rate) {
 	instance->Ttm2pi = -6.283185307179586f / sample_rate;
 }
 
-void bw_one_pole_reset(bw_one_pole instance) {
+void bw_one_pole_reset(bw_one_pole *instance) {
 	instance->first_run = 1;
 	instance->param_changed = ~0;
 }
@@ -71,7 +41,7 @@ void bw_one_pole_reset(bw_one_pole instance) {
 #define PARAM_CUTOFF_DOWN	(1<<1)
 #define PARAM_STICKY_THRESH	(1<<2)
 
-void bw_one_pole_process(bw_one_pole instance, const float* x, float* y, int n_samples) {
+void bw_one_pole_process(bw_one_pole *instance, const float* x, float* y, int n_samples) {
 	if (instance->param_changed) {
 		if (instance->param_changed & PARAM_CUTOFF_UP)
 			instance->mA1u = bw_expf_3(instance->Ttm2pi * instance->cutoff_up);
@@ -160,51 +130,51 @@ void bw_one_pole_process(bw_one_pole instance, const float* x, float* y, int n_s
 	}
 }
 
-void bw_one_pole_set_init_val(bw_one_pole instance, float value) {
+void bw_one_pole_set_init_val(bw_one_pole *instance, float value) {
 	instance->init_val = value;
 }
 
-void bw_one_pole_set_cutoff(bw_one_pole instance, float value) {
+void bw_one_pole_set_cutoff(bw_one_pole *instance, float value) {
 	bw_one_pole_set_cutoff_up(instance, value);
 	bw_one_pole_set_cutoff_down(instance, value);
 }
 
-void bw_one_pole_set_cutoff_up(bw_one_pole instance, float value) {
+void bw_one_pole_set_cutoff_up(bw_one_pole *instance, float value) {
 	if (instance->cutoff_up != value) {
 		instance->cutoff_up = value;
 		instance->param_changed |= PARAM_CUTOFF_UP;
 	}
 }
 
-void bw_one_pole_set_cutoff_down(bw_one_pole instance, float value) {
+void bw_one_pole_set_cutoff_down(bw_one_pole *instance, float value) {
 	if (instance->cutoff_down != value) {
 		instance->cutoff_down = value;
 		instance->param_changed |= PARAM_CUTOFF_DOWN;
 	}
 }
 
-void bw_one_pole_set_tau(bw_one_pole instance, float value) {
+void bw_one_pole_set_tau(bw_one_pole *instance, float value) {
 	bw_one_pole_set_tau_up(instance, value);
 	bw_one_pole_set_tau_down(instance, value);
 }
 
-void bw_one_pole_set_tau_up(bw_one_pole instance, float value) {
+void bw_one_pole_set_tau_up(bw_one_pole *instance, float value) {
 	bw_one_pole_set_cutoff_up(instance, value < 1e-9f ? INFINITY : 0.1591549430918953f * bw_rcpf_2(value));
 	// tau < 1 ns is instantaneous for any practical purpose
 }
 
-void bw_one_pole_set_tau_down(bw_one_pole instance, float value) {
+void bw_one_pole_set_tau_down(bw_one_pole *instance, float value) {
 	bw_one_pole_set_cutoff_down(instance, value < 1e-9f ? INFINITY : 0.1591549430918953f * bw_rcpf_2(value));
 	// as before
 }
 
-void bw_one_pole_set_sticky_thresh(bw_one_pole instance, float value) {
+void bw_one_pole_set_sticky_thresh(bw_one_pole *instance, float value) {
 	if (instance->sticky_thresh != value) {
 		instance->sticky_thresh = value;
 		instance->param_changed |= PARAM_STICKY_THRESH;
 	}
 }
 
-void bw_one_pole_set_sticky_mode(bw_one_pole instance, bw_one_pole_sticky_mode value) {
+void bw_one_pole_set_sticky_mode(bw_one_pole *instance, bw_one_pole_sticky_mode value) {
 	instance->sticky_mode = value;
 }
diff --git a/src/bw_osc_filt.c b/src/bw_osc_filt.c
index 99138a2..90980a8 100644
--- a/src/bw_osc_filt.c
+++ b/src/bw_osc_filt.c
@@ -21,35 +21,16 @@
 
 #include <bw_common.h>
 
-struct _bw_osc_filt {
-	// Parameters
-	char	enabled;
-
-	// State
-	float	x_z1;
-	float	y_z1;
-};
-
-bw_osc_filt bw_osc_filt_new() {
-	bw_osc_filt instance = (bw_osc_filt)BW_MALLOC(sizeof(struct _bw_osc_filt));
-	if (instance == NULL)
-		return NULL;
-
+void bw_osc_filt_init(bw_osc_filt *instance) {
 	instance->enabled = 1;
-
-	return instance;
 }
 
-void bw_osc_filt_free(bw_osc_filt instance) {
-	BW_FREE(instance);
-}
-
-void bw_osc_filt_reset(bw_osc_filt instance) {
+void bw_osc_filt_reset(bw_osc_filt *instance) {
 	instance->x_z1 = 0.f;
 	instance->y_z1 = 0.f;
 }
 
-void bw_osc_filt_process(bw_osc_filt instance, const float *x, float* y, int n_samples) {
+void bw_osc_filt_process(bw_osc_filt *instance, const float *x, float* y, int n_samples) {
 	if (instance->enabled)
 		for (int i = 0; i < n_samples; i++) {
 			const float v = 1.371308261611209f * x[i] + 0.08785458027104826f * instance->x_z1 - 4.591628418822578e-1f * instance->y_z1;
@@ -65,6 +46,6 @@ void bw_osc_filt_process(bw_osc_filt instance, const float *x, float* y, int n_s
 
 }
 
-void bw_osc_filt_set_enabled(bw_osc_filt instance, char value) {
+void bw_osc_filt_set_enabled(bw_osc_filt *instance, char value) {
 	instance->enabled = value;
 }
diff --git a/src/bw_osc_pulse.c b/src/bw_osc_pulse.c
index 912003d..dfc02a3 100644
--- a/src/bw_osc_pulse.c
+++ b/src/bw_osc_pulse.c
@@ -22,39 +22,16 @@
 #include <bw_math.h>
 #include <bw_inline_one_pole.h>
 
-struct _bw_osc_pulse {
-	// Coefficients
-	float	smooth_mA1;
-
-	// Parameters
-	char	first_run;
-	char	antialiasing;
-	float	pulse_width;
-
-	// State
-	float	pw_z1;
-};
-
-bw_osc_pulse bw_osc_pulse_new() {
-	bw_osc_pulse instance = (bw_osc_pulse)BW_MALLOC(sizeof(struct _bw_osc_pulse));
-	if (instance == NULL)
-		return NULL;
-
+void bw_osc_pulse_init(bw_osc_pulse *instance) {
 	instance->antialiasing = 0;
 	instance->pulse_width = 0.5f;
-
-	return instance;
 }
 
-void bw_osc_pulse_free(bw_osc_pulse instance) {
-	BW_FREE(instance);
-}
-
-void bw_osc_pulse_set_sample_rate(bw_osc_pulse instance, float sample_rate) {
+void bw_osc_pulse_set_sample_rate(bw_osc_pulse *instance, float sample_rate) {
 	instance->smooth_mA1 = bw_inline_one_pole_get_mA1(sample_rate, 0.005f);
 }
 
-void bw_osc_pulse_reset(bw_osc_pulse instance) {
+void bw_osc_pulse_reset(bw_osc_pulse *instance) {
 	instance->first_run = 1;
 }
 
@@ -65,7 +42,7 @@ static inline float blep_diff(float x) {
 		: x * (x * ((0.6666666666666666f - 0.08333333333333333f * x) * x - 2.0f) + 2.666666666666667f) - 1.333333333333333f;
 }
 
-void bw_osc_pulse_process(bw_osc_pulse instance, const float *x, const float *x_phase_inc, float* y, int n_samples) {
+void bw_osc_pulse_process(bw_osc_pulse *instance, const float *x, const float *x_phase_inc, float* y, int n_samples) {
 	if (instance->first_run) {
 		instance->pw_z1 = instance->pulse_width;
 		instance->first_run = 0;
@@ -107,10 +84,10 @@ void bw_osc_pulse_process(bw_osc_pulse instance, const float *x, const float *x_
 	}
 }
 
-void bw_osc_pulse_set_antialiasing(bw_osc_pulse instance, char value) {
+void bw_osc_pulse_set_antialiasing(bw_osc_pulse *instance, char value) {
 	instance->antialiasing = value;
 }
 
-void bw_osc_pulse_set_pulse_width(bw_osc_pulse instance, float value) {
+void bw_osc_pulse_set_pulse_width(bw_osc_pulse *instance, float value) {
 	instance->pulse_width = value;
 }
diff --git a/src/bw_osc_saw.c b/src/bw_osc_saw.c
index fc1b9d2..282a71d 100644
--- a/src/bw_osc_saw.c
+++ b/src/bw_osc_saw.c
@@ -21,23 +21,8 @@
 
 #include <bw_math.h>
 
-struct _bw_osc_saw {
-	// Parameters
-	char	antialiasing;
-};
-
-bw_osc_saw bw_osc_saw_new() {
-	bw_osc_saw instance = (bw_osc_saw)BW_MALLOC(sizeof(struct _bw_osc_saw));
-	if (instance == NULL)
-		return NULL;
-
+void bw_osc_saw_init(bw_osc_saw *instance) {
 	instance->antialiasing = 0;
-
-	return instance;
-}
-
-void bw_osc_saw_free(bw_osc_saw instance) {
-	BW_FREE(instance);
 }
 
 // PolyBLEP residual based on Parzen window (4th-order B-spline), one-sided (x in [0, 2])
@@ -47,7 +32,7 @@ static inline float blep_diff(float x) {
 		: x * (x * ((0.6666666666666666f - 0.08333333333333333f * x) * x - 2.0f) + 2.666666666666667f) - 1.333333333333333f;
 }
 
-void bw_osc_saw_process(bw_osc_saw instance, const float *x, const float *x_phase_inc, float* y, int n_samples) {
+void bw_osc_saw_process(bw_osc_saw *instance, const float *x, const float *x_phase_inc, float* y, int n_samples) {
 	if (instance->antialiasing) {
 		for (int i = 0; i < n_samples; i++) {
 			const float s_1_m_phase = 1.f - x[i];
@@ -70,6 +55,6 @@ void bw_osc_saw_process(bw_osc_saw instance, const float *x, const float *x_phas
 	}
 }
 
-void bw_osc_saw_set_antialiasing(bw_osc_saw instance, char value) {
+void bw_osc_saw_set_antialiasing(bw_osc_saw *instance, char value) {
 	instance->antialiasing = value;
 }
diff --git a/src/bw_osc_tri.c b/src/bw_osc_tri.c
index c0852b8..d41d66e 100644
--- a/src/bw_osc_tri.c
+++ b/src/bw_osc_tri.c
@@ -22,39 +22,16 @@
 #include <bw_math.h>
 #include <bw_inline_one_pole.h>
 
-struct _bw_osc_tri {
-	// Coefficients
-	float	smooth_mA1;
-
-	// Parameters
-	char	first_run;
-	char	antialiasing;
-	float	slope;
-
-	// State
-	float	slope_z1;
-};
-
-bw_osc_tri bw_osc_tri_new() {
-	bw_osc_tri instance = (bw_osc_tri)BW_MALLOC(sizeof(struct _bw_osc_tri));
-	if (instance == NULL)
-		return NULL;
-
+void bw_osc_tri_init(bw_osc_tri *instance) {
 	instance->antialiasing = 0;
 	instance->slope = 0.5f;
-
-	return instance;
 }
 
-void bw_osc_tri_free(bw_osc_tri instance) {
-	BW_FREE(instance);
-}
-
-void bw_osc_tri_set_sample_rate(bw_osc_tri instance, float sample_rate) {
+void bw_osc_tri_set_sample_rate(bw_osc_tri *instance, float sample_rate) {
 	instance->smooth_mA1 = bw_inline_one_pole_get_mA1(sample_rate, 0.005f);
 }
 
-void bw_osc_tri_reset(bw_osc_tri instance) {
+void bw_osc_tri_reset(bw_osc_tri *instance) {
 	instance->first_run = 1;
 }
 
@@ -65,7 +42,7 @@ static inline float blamp_diff(float x) {
 		: x * (x * (x * ((0.1666666666666667f - 0.01666666666666667f * x) * x - 0.6666666666666666f) + 1.333333333333333f) - 1.333333333333333f) + 0.5333333333333333f;
 }
 
-void bw_osc_tri_process(bw_osc_tri instance, const float *x, const float *x_phase_inc, float* y, int n_samples) {
+void bw_osc_tri_process(bw_osc_tri *instance, const float *x, const float *x_phase_inc, float* y, int n_samples) {
 	if (instance->first_run) {
 		instance->slope_z1 = instance->slope;
 		instance->first_run = 0;
@@ -113,10 +90,10 @@ void bw_osc_tri_process(bw_osc_tri instance, const float *x, const float *x_phas
 	}
 }
 
-void bw_osc_tri_set_antialiasing(bw_osc_tri instance, char value) {
+void bw_osc_tri_set_antialiasing(bw_osc_tri *instance, char value) {
 	instance->antialiasing = value;
 }
 
-void bw_osc_tri_set_slope(bw_osc_tri instance, float value) {
+void bw_osc_tri_set_slope(bw_osc_tri *instance, float value) {
 	instance->slope = value;
 }
diff --git a/src/bw_phase_gen.c b/src/bw_phase_gen.c
index cbdbada..2c6a808 100644
--- a/src/bw_phase_gen.c
+++ b/src/bw_phase_gen.c
@@ -21,43 +21,16 @@
 
 #include <bw_math.h>
 
-struct _bw_phase_gen {
-	// Coefficients
-	float		T;
-
-	float		portamento_target;
-	float		portamento_mA1;
-
-	// Parameters
-	float		frequency;
-	float		portamento_tau;
-	int		param_changed;
-
-	// State
-	char		first_run;
-	float		phase;
-	float		portamento_z1;
-};
-
-bw_phase_gen bw_phase_gen_new() {
-	bw_phase_gen instance = (bw_phase_gen)BW_MALLOC(sizeof(struct _bw_phase_gen));
-	if (instance == NULL)
-		return NULL;
-
+void bw_phase_gen_init(bw_phase_gen *instance) {
 	instance->frequency = 1.f;
 	instance->portamento_tau = 0.f;
-	return instance;
 }
 
-void bw_phase_gen_free(bw_phase_gen instance) {
-	BW_FREE(instance);
-}
-
-void bw_phase_gen_set_sample_rate(bw_phase_gen instance, float sample_rate) {
+void bw_phase_gen_set_sample_rate(bw_phase_gen *instance, float sample_rate) {
 	instance->T = 1.f / sample_rate;
 }
 
-void bw_phase_gen_reset(bw_phase_gen instance) {
+void bw_phase_gen_reset(bw_phase_gen *instance) {
 	instance->first_run = 1;
 	instance->param_changed = ~0;
 }
@@ -65,7 +38,7 @@ void bw_phase_gen_reset(bw_phase_gen instance) {
 #define PARAM_FREQUENCY		1
 #define PARAM_PORTAMENTO_TAU	(1<<1)
 
-void bw_phase_gen_process(bw_phase_gen instance, const float *x_mod, float* y, float *y_phase_inc, int n_samples) {
+void bw_phase_gen_process(bw_phase_gen *instance, const float *x_mod, float* y, float *y_phase_inc, int n_samples) {
 	if (instance->param_changed) {
 		if (instance->param_changed & PARAM_FREQUENCY)
 			instance->portamento_target = instance->T * instance->frequency;
@@ -107,14 +80,14 @@ void bw_phase_gen_process(bw_phase_gen instance, const float *x_mod, float* y, f
 		}
 }
 
-void bw_phase_gen_set_frequency(bw_phase_gen instance, float value) {
+void bw_phase_gen_set_frequency(bw_phase_gen *instance, float value) {
 	if (instance->frequency != value) {
 		instance->frequency = value;
 		instance->param_changed |= PARAM_FREQUENCY;
 	}
 }
 
-void bw_phase_gen_set_portamento_tau(bw_phase_gen instance, float value) {
+void bw_phase_gen_set_portamento_tau(bw_phase_gen *instance, float value) {
 	if (instance->portamento_tau != value) {
 		instance->portamento_tau = value;
 		instance->param_changed |= PARAM_PORTAMENTO_TAU;
diff --git a/src/bw_slew_lim.c b/src/bw_slew_lim.c
index b281916..ed69b27 100644
--- a/src/bw_slew_lim.c
+++ b/src/bw_slew_lim.c
@@ -21,44 +21,22 @@
 
 #include <bw_math.h>
 
-struct _bw_slew_lim {
-	// Coefficients
-	float	T;
-
-	// Parameters
-	float	init_val;
-	float	max_inc_rate;
-	float	max_dec_rate;
-
-	// State
-	char	first_run;
-	float	y_z1;
-};
-
-bw_slew_lim bw_slew_lim_new() {
-	bw_slew_lim instance = (bw_slew_lim)BW_MALLOC(sizeof(struct _bw_slew_lim));
-	if (instance != NULL) {
-		instance->init_val = 0.f;
-		instance->max_inc = INFINITY;
-		instance->max_dec = INFINITY;
-	}
-	return instance;
+void bw_slew_lim_init(bw_slew_lim *instance) {
+	instance->init_val = 0.f;
+	instance->max_inc = INFINITY;
+	instance->max_dec = INFINITY;
 }
 
-void bw_slew_lim_free(bw_slew_lim instance) {
-	BW_FREE(instance);
-}
-
-void bw_slew_lim_set_sample_rate(bw_slew_lim instance, float sample_rate) {
+void bw_slew_lim_set_sample_rate(bw_slew_lim *instance, float sample_rate) {
 	instance->T = 1.f / sample_rate;
 }
 
-void bw_slew_lim_reset(bw_slew_lim instance) {
+void bw_slew_lim_reset(bw_slew_lim *instance) {
 	instance->first_run = 1;
 	instance->param_changed = ~0;
 }
 
-void bw_slew_lim_process(bw_slew_lim instance, const float* x, float* y, int n_samples) {
+void bw_slew_lim_process(bw_slew_lim *instance, const float* x, float* y, int n_samples) {
 	if (instance->first_run) {
 		instance->y_z1 = instance->init_val;
 		instance->first_run = 0;
@@ -93,19 +71,19 @@ void bw_slew_lim_process(bw_slew_lim instance, const float* x, float* y, int n_s
 	}
 }
 
-void bw_slew_lim_set_init_val(bw_slew_lim instance, float value) {
+void bw_slew_lim_set_init_val(bw_slew_lim *instance, float value) {
 	instance->init_val = value;
 }
 
-void bw_slew_lim_set_max_rate(bw_slew_lim instance, float value) {
+void bw_slew_lim_set_max_rate(bw_slew_lim *instance, float value) {
 	instance->max_inc_rate = value;
 	instance->max_dec_rate = value;
 }
 
-void bw_slew_lim_set_max_inc_rate(bw_slew_lim instance, float value) {
+void bw_slew_lim_set_max_inc_rate(bw_slew_lim *instance, float value) {
 	instance->max_inc_rate = value;
 }
 
-void bw_slew_lim_set_max_dec_rate(bw_slew_lim instance, float value) {
+void bw_slew_lim_set_max_dec_rate(bw_slew_lim *instance, float value) {
 	instance->max_dec_rate = value;
 }
diff --git a/src/bw_svf.c b/src/bw_svf.c
index 74dd43b..f78272e 100644
--- a/src/bw_svf.c
+++ b/src/bw_svf.c
@@ -22,59 +22,24 @@
 #include <bw_math.h>
 #include <bw_inline_one_pole.h>
 
-struct _bw_svf {
-	// Coefficients
-	float	t_k;
-	float	smooth_mA1;
-
-	float	t;
-	float	k;
-	float	hp_hp_z1;
-	float	hp_bp_z1;
-	float	hp_x;
-
-	// Parameters
-	float	cutoff;
-	float	Q;
-
-	float	cutoff_cur;
-	float	Q_cur;
-
-	// State
-	char	first_run;
-	float	hp_z1;
-	float	lp_z1;
-	float	bp_z1;
-};
-
-bw_svf bw_svf_new() {
-	bw_svf instance = (bw_svf)BW_MALLOC(sizeof(struct _bw_svf));
-	if (instance == NULL)
-		return NULL;
-
+void bw_svf_init(bw_svf *instance) {
 	instance->cutoff = 1e3f;
 	instance->Q = 0.5f;
-
-	return instance;
 }
 
-void bw_svf_free(bw_svf instance) {
-	BW_FREE(instance);
-}
-
-void bw_svf_set_sample_rate(bw_svf instance, float sample_rate) {
+void bw_svf_set_sample_rate(bw_svf *instance, float sample_rate) {
 	instance->t_k = 3.141592653589793f / sample_rate;
 	instance->smooth_mA1 = bw_inline_one_pole_get_mA1(sample_rate, 0.05f);
 }
 
-void bw_svf_reset(bw_svf instance) {
+void bw_svf_reset(bw_svf *instance) {
 	instance->first_run = 1;
 }
 
 #define PARAM_CUTOFF	1
 #define PARAM_Q		(1<<1)
 
-static inline void update_coefficients(bw_svf instance) {
+static inline void update_coefficients(bw_svf *instance) {
 	const char cutoff_changed = instance->cutoff != instance->cutoff_cur || instance->first_run;
 	const char Q_changed = instance->Q != instance->Q_cur || instance->first_run;
 	if (cutoff_changed || Q_changed) {
@@ -93,7 +58,7 @@ static inline void update_coefficients(bw_svf instance) {
 	}
 }
 
-void bw_svf_process(bw_svf instance, const float *x, float *y_lp, float *y_bp, float *y_hp, int n_samples) {
+void bw_svf_process(bw_svf *instance, const float *x, float *y_lp, float *y_bp, float *y_hp, int n_samples) {
 	if (instance->first_run) {
 		instance->cutoff_cur = instance->cutoff;
 		instance->Q_cur = instance->Q;
@@ -122,10 +87,10 @@ void bw_svf_process(bw_svf instance, const float *x, float *y_lp, float *y_bp, f
 	}
 }
 
-void bw_svf_set_cutoff(bw_svf instance, float value) {
+void bw_svf_set_cutoff(bw_svf *instance, float value) {
 	instance->cutoff = value;
 }
 
-void bw_svf_set_Q(bw_svf instance, float value) {
+void bw_svf_set_Q(bw_svf *instance, float value) {
 	instance->Q = value;
 }
diff --git a/src/bw_vol.c b/src/bw_vol.c
index a48a87f..3f79993 100644
--- a/src/bw_vol.c
+++ b/src/bw_vol.c
@@ -21,56 +21,28 @@
 
 #include <bw_inline_slew_lim.h>
 
-#define BUFFER_SIZE	32
-
-struct _bw_vol {
-	// Coefficients
-	float	max_var;
-
-	// Parameters
-	float	volume;
-
-	float	volume_cur;
-
-	// State
-	char	first_run;
-
-	// Buffers
-	float	buf[BUFFER_SIZE];
-};
-
-bw_vol bw_vol_new() {
-	bw_vol instance = (bw_vol)BW_MALLOC(sizeof(struct _bw_vol));
-	if (instance == NULL)
-		return NULL;
-
+void bw_vol_init(bw_vol *instance) {
 	instance->volume = 1.f;
-
-	return instance;
 }
 
-void bw_vol_free(bw_vol instance) {
-	BW_FREE(instance);
-}
-
-void bw_vol_set_sample_rate(bw_vol instance, float sample_rate) {
+void bw_vol_set_sample_rate(bw_vol *instance, float sample_rate) {
 	instance->max_var = bw_inline_slew_lim_get_max_var(sample_rate, 1.f / 0.05f);
 }
 
-void bw_vol_reset(bw_vol instance) {
+void bw_vol_reset(bw_vol *instance) {
 	instance->first_run = 1;
 }
 
-void bw_vol_process(bw_vol instance, const float **x, float **y, int n_channels, int n_samples) {
+void bw_vol_process(bw_vol *instance, const float **x, float **y, int n_channels, int n_samples) {
 	if (instance->first_run) {
 		instance->volume_cur = instance->volume;
 		instance->first_run = 0;
 	}
 
-	for (int i = 0; i < n_samples; i += BUFFER_SIZE) {
-		const uint32_t n = bw_minu32(n_samples - i, BUFFER_SIZE);
+	for (int i = 0; i < n_samples; i += _BW_VOL_BUFFER_SIZE) {
+		const uint32_t n = bw_minu32(n_samples - i, _BW_VOL_BUFFER_SIZE);
 
-		for (int j = 0; j < BUFFER_SIZE; j++) {
+		for (int j = 0; j < _BW_VOL_BUFFER_SIZE; j++) {
 			instance->volume_cur = bw_inline_slew_lim(instance->volume, instance->volume_cur, instance->max_var, instance->max_var);
 			instance->buf[j] = instance->volume_cur * instance->volume_cur * instance->volume_cur;
 		}
@@ -78,12 +50,12 @@ void bw_vol_process(bw_vol instance, const float **x, float **y, int n_channels,
 		for (int j = 0; j < n_channels; j++) {
 			const float *in = x[j] + i;
 			float *out = y[j] + i;
-			for (int k = 0; k < BUFFER_SIZE; k++)
+			for (int k = 0; k < _BW_VOL_BUFFER_SIZE; k++)
 				out[k] = instance->buf[k] * in[k];
 		}
 	}
 }
 
-void bw_vol_set_volume(bw_vol instance, float value) {
+void bw_vol_set_volume(bw_vol *instance, float value) {
 	instance->volume = value;
 }