diff --git a/TODO b/TODO
index 3e815b5..3fe6906 100644
--- a/TODO
+++ b/TODO
@@ -8,6 +8,7 @@ code:
 * API for buffer fill, scale, offset, zero, copy...?
 * web examples construction/destruction
 * web effect multichannel in?
+* check const restrict etc.
 
 build system:
 * make makefiles handle paths with spaces etc
diff --git a/include/bw_common.h b/include/bw_common.h
index 7fccbdc..69eef46 100644
--- a/include/bw_common.h
+++ b/include/bw_common.h
@@ -27,6 +27,11 @@
  *  }}}
  *  changelog {{{
  *    <ul>
+ *      <li>Version <strong>0.2.0</strong>:
+ *        <ul>
+ *          <li>Removed BW_MALLOC, BW_REALLOC, and BW_FREE.</li>
+ *        </ul>
+ *      </li>
  *      <li>Version <strong>0.1.0</strong>:
  *        <ul>
  *          <li>First release.</li>
@@ -77,24 +82,6 @@
 # include <math.h>
 #endif
 
-/*! ...
- *    #### BW_MALLOC, BW_REALLOC, BW_FREE
- *    If any of these is not defined, then `stdlib.h` is `#include`d and the
- *    missing ones are defined as `malloc`, `realloc`, or `free`, respectively.
- *  >>> */
-#if !defined(BW_MALLOC) || !defined(BW_REALLOC) || !defined(BW_FREE)
-# include <stdlib.h>
-# ifndef BW_MALLOC
-#  define BW_MALLOC malloc
-# endif
-# ifndef BW_REALLOC
-#  define BW_REALLOC realloc
-# endif
-# ifndef BW_FREE
-#  define BW_FREE free
-# endif
-#endif
-
 /*! ... }}} */
 
 #endif
diff --git a/include/bw_env_follow.h b/include/bw_env_follow.h
index 1b47aa2..29d217c 100644
--- a/include/bw_env_follow.h
+++ b/include/bw_env_follow.h
@@ -120,7 +120,8 @@ bw_one_pole *bw_env_follow_get_one_pole(bw_env_follow *instance);
  * access its members directly. */
 struct _bw_env_follow {
 	// Sub-components
-	bw_one_pole	one_pole;
+	bw_one_pole_coeffs	one_pole_coeffs;
+	bw_one_pole_state	one_pole_state;
 };
 
 #ifdef __cplusplus
diff --git a/include/bw_env_gen.h b/include/bw_env_gen.h
index 33d90e0..729c638 100644
--- a/include/bw_env_gen.h
+++ b/include/bw_env_gen.h
@@ -20,7 +20,7 @@
 /*!
  *  module_type {{{ dsp }}}
  *  version {{{ 0.2.0 }}}
- *  requires {{{ bw_config bw_common bw_inline_one_pole bw_math }}}
+ *  requires {{{ bw_config bw_common bw_one_pole bw_math }}}
  *  description {{{
  *    Linear ADSR envelope generator.
  *
diff --git a/include/bw_inline_one_pole.h b/include/bw_inline_one_pole.h
deleted file mode 100644
index 3ea2a8c..0000000
--- a/include/bw_inline_one_pole.h
+++ /dev/null
@@ -1,118 +0,0 @@
-/*
- * Brickworks
- *
- * Copyright (C) 2022 Orastron Srl unipersonale
- *
- * Brickworks is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, version 3 of the License.
- *
- * Brickworks is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- *
- * File author: Stefano D'Angelo
- */
-
-/*!
- *  module_type {{{ utility }}}
- *  version {{{ 0.1.0 }}}
- *  requires {{{ bw_config bw_common bw_math }}}
- *  description {{{
- *    Inline one-pole (6 dB/oct) lowpass filter with unitary DC gain and sticky
- *    target-reach threshold.
- *
- *    This is similar to [bw_one_pole](bw_one_pole) but can be used to process
- *    on a sample-by-sample basis without buffers.
- *  }}}
- *  changelog {{{
- *    <ul>
- *      <li>Version <strong>0.1.0</strong>:
- *        <ul>
- *          <li>First release.</li>
- *        </ul>
- *      </li>
- *    </ul>
- *  }}}
- */
-
-#ifndef _BW_INLINE_ONE_POLE_H
-#define _BW_INLINE_ONE_POLE_H
-
-#include <bw_math.h>
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-/*! api {{{
- *    #### bw_inline_one_pole_get_mA1()
- *  ```>>> */
-static inline float bw_inline_one_pole_get_mA1(float sample_rate, float tau);
-/*! <<<```
- *    Computes the `mA1` coefficient requested by other functions in this
- *    module, corresponding to the given `sample_rate` (Hz) and time constant
- *    `tau` (s) values.
- *  >>> */
-
-/*! ...
- *    #### bw_inline_one_pole()
- *  ```>>> */
-static inline float bw_inline_one_pole(float x, float y_z1, float mA1);
-/*! <<<```
- *    Processes one input sample `x`, using the previous output value `y_z1` and
- *    the `mA1` coefficient, and returns the corresponding output sample.
- *
- *    This function does not feature sticky target-reach threshold.
- *  >>> */
-
-/*! ...
- *    #### bw_inline_one_pole_sticky_abs()
- *  ```>>> */
-static inline float bw_inline_one_pole_sticky_abs(float x, float y_z1, float mA1, float thresh_sq);
-/*! <<<```
- *    Like `bw_inline_one_pole()` but when the absolute difference between the
- *    output and the input (|*value to be returned* - `x`|) would be smaller
- *    than the square root of `thresh_sq`, it just returns `x`.
- *  >>> */
-
-/*! ...
- *    #### bw_inline_one_pole_sticky_rel()
- *  ```>>> */
-static inline float bw_inline_one_pole_sticky_rel(float x, float y_z1, float mA1, float thresh_sq);
-/*! <<<```
- *    Like `bw_inline_one_pole()` but when the relative difference of the output
- *    with respect to the input (|*value to be returned* - `x`| / |`x`|) would
- *    be smaller than the square root of `thresh_sq`, it just returns `x`.
- *  }}} */
-
-/* Implementation */
-
-static inline float bw_inline_one_pole_get_mA1(float sample_rate, float tau) {
-	return bw_expf_3(-bw_rcpf_2(sample_rate * tau));
-}
-
-static inline float bw_inline_one_pole(float x, float y_z1, float mA1) {
-	return x + mA1 * (y_z1 - x);
-}
-
-static inline float bw_inline_one_pole_sticky_abs(float x, float y_z1, float mA1, float thresh_sq) {
-	float y = bw_inline_one_pole(x, y_z1, mA1);
-	const float d = x - y;
-	return d * d < thresh_sq ? x : y;
-}
-
-static inline float bw_inline_one_pole_sticky_rel(float x, float y_z1, float mA1, float thresh_sq) {
-	float y = bw_inline_one_pole(x, y_z1, mA1);
-	const float d = x - y;
-	return d * d < thresh_sq * (x * x) ? x : y;
-}
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif
diff --git a/include/bw_math.h b/include/bw_math.h
index db90cea..3d928d8 100644
--- a/include/bw_math.h
+++ b/include/bw_math.h
@@ -363,7 +363,10 @@ static inline float bw_sqrtf_2(float x);
  *    Relative error < 0.0007%.
  *  }}} */
 
-/* Implementation */
+/*** Implementation ***/
+
+/* WARNING: This part of the file is not part of the public API. Its content may
+ * change at any time in future versions. Please, do not use it directly. */
 
 typedef union {
 	float f;
diff --git a/include/bw_one_pole.h b/include/bw_one_pole.h
index b2fa1c4..e674d99 100644
--- a/include/bw_one_pole.h
+++ b/include/bw_one_pole.h
@@ -29,7 +29,7 @@
  *    <ul>
  *      <li>Version <strong>0.2.0</strong>:
  *        <ul>
- *          <li>Refactored API to avoid dynamic memory allocation.</li>
+ *          <li>Refactored API.</li>
  *        </ul>
  *      </li>
  *      <li>Version <strong>0.1.0</strong>:
@@ -49,14 +49,18 @@ extern "C" {
 #endif
 
 /*! api {{{
- *    #### bw_one_pole
+ *    #### bw_one_pole_coeffs
  *  ```>>> */
-typedef struct _bw_one_pole bw_one_pole;
+typedef struct _bw_one_pole_coeffs bw_one_pole_coeffs;
 /*! <<<```
- *    Instance object.
+ *    Coefficients.
+ *
+ *    ### bw_one_pole_state
  *  >>> */
- 
-/*! ...
+typedef struct _bw_one_pole_state bw_one_pole_state;
+/*! <<<```
+ *    State.
+ *
  *    #### bw_one_pole_sticky_mode
  *  ```>>> */
 typedef enum {
@@ -68,36 +72,42 @@ typedef enum {
  *     * `bw_one_pole_sticky_mode_abs`: absolute difference (|`out` - `in`|);
  *     * `bw_one_pole_sticky_mode_rel`: relative difference with respect to
  *       input (|`out` - `in`| / |`in`|);
- *  >>> */
-
-/*! ...
+ *
  *    #### bw_one_pole_init()
  *  ```>>> */
-void bw_one_pole_init(bw_one_pole *instance);
+static inline void bw_one_pole_init(bw_one_pole_coeffs *restrict coeffs);
 /*! <<<```
- *    Initializes the `instance` object.
- *  >>> */
-
-/*! ...
+ *    Initializes `coeffs`.
+ *
  *    #### bw_one_pole_set_sample_rate()
  *  ```>>> */
-void bw_one_pole_set_sample_rate(bw_one_pole *instance, float sample_rate);
+static inline void bw_one_pole_set_sample_rate(bw_one_pole_coeffs *restrict coeffs, float sample_rate);
 /*! <<<```
- *    Sets the `sample_rate` (Hz) value for the given `instance`.
+ *    Sets the `sample_rate` (Hz) value for the given `coeffs`.
+ *
+ *    #### bw_one_pole_reset_state()
+ *  ```>>> */
+static inline void bw_one_pole_reset_state(const bw_one_pole_coeffs *restrict coeffs, bw_one_pole_state *restrict state);
+/*! <<<```
+ *    Resets the given `state` to the initial state using the given `coeffs`.
  *  >>> */
 
-/*! ...
- *    #### bw_one_pole_reset()
- *  ```>>> */
-void bw_one_pole_reset(bw_one_pole *instance);
-/*! <<<```
- *    Resets the given `instance` to its initial state.
- *  >>> */
+static inline void bw_one_pole_reset_coeffs(bw_one_pole_coeffs *restrict coeffs);
+
+static inline void bw_one_pole_update_coeffs_ctrl(bw_one_pole_coeffs *restrict coeffs);
+static inline void bw_one_pole_update_coeffs_audio(bw_one_pole_coeffs *restrict coeffs);
+
+static inline float bw_one_pole_process1(const bw_one_pole_coeffs *restrict coeffs, bw_one_pole_state *restrict state, float x);
+static inline float bw_one_pole_process1_sticky_abs(const bw_one_pole_coeffs *restrict coeffs, bw_one_pole_state *restrict state, float x);
+static inline float bw_one_pole_process1_sticky_rel(const bw_one_pole_coeffs *restrict coeffs, bw_one_pole_state *restrict state, float x);
+static inline float bw_one_pole_process1_asym(const bw_one_pole_coeffs *restrict coeffs, bw_one_pole_state *restrict state, float x);
+static inline float bw_one_pole_process1_asym_sticky_abs(const bw_one_pole_coeffs *restrict coeffs, bw_one_pole_state *restrict state, float x);
+static inline float bw_one_pole_process1_asym_sticky_rel(const bw_one_pole_coeffs *restrict coeffs, bw_one_pole_state *restrict state, float x);
 
 /*! ...
  *    #### bw_one_pole_process()
  *  ```>>> */
-void bw_one_pole_process(bw_one_pole *instance, const float* x, float* y, int n_samples);
+static inline void bw_one_pole_process(bw_one_pole_coeffs *restrict coeffs, bw_one_pole_state *restrict state, 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
@@ -107,7 +117,7 @@ void bw_one_pole_process(bw_one_pole *instance, const float* x, float* y, int n_
 /*! ...
  *    #### bw_one_pole_set_init_val()
  *  ```>>> */
-void bw_one_pole_set_init_val(bw_one_pole *instance, float value);
+static inline void bw_one_pole_set_init_val(bw_one_pole_coeffs *restrict coeffs, float value);
 /*! <<<```
  *    Sets the initial/quiescent `value` for the given `instance`.
  *
@@ -121,7 +131,7 @@ 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);
+static inline void bw_one_pole_set_cutoff(bw_one_pole_coeffs *restrict coeffs, float value);
 /*! <<<```
  *    Sets both the upgoing (attack) and downgoing (decay) cutoff frequency to
  *    the given `value` (Hz) for the given `instance`.
@@ -137,7 +147,7 @@ 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);
+static inline void bw_one_pole_set_cutoff_up(bw_one_pole_coeffs *restrict coeffs, float value);
 /*! <<<```
  *    Sets the upgoing (attack) cutoff frequency to the given `value` (Hz) for
  *    the given `instance`.
@@ -151,7 +161,7 @@ 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);
+static inline void bw_one_pole_set_cutoff_down(bw_one_pole_coeffs *restrict coeffs, float value);
 /*! <<<```
  *    Sets the downgoing (attack) cutoff frequency to the given `value` (Hz)
  *    for the given `instance`.
@@ -165,7 +175,7 @@ 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);
+static inline void bw_one_pole_set_tau(bw_one_pole_coeffs *restrict coeffs, float value);
 /*! <<<```
  *    Sets both the upgoing (attack) and downgoing (decay) time constant to the
  *    given `value` (s) for the given `instance`.
@@ -181,7 +191,7 @@ 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);
+static inline void bw_one_pole_set_tau_up(bw_one_pole_coeffs *restrict coeffs, float value);
 /*! <<<```
  *    Sets the upgoing (attack) time constant to the given `value` (s) for the
  *    given `instance`.
@@ -195,7 +205,7 @@ 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);
+static inline void bw_one_pole_set_tau_down(bw_one_pole_coeffs *restrict coeffs, float value);
 /*! <<<```
  *    Sets the downgoing (decay) time constant to the given `value` (s) for the
  *    given `instance`.
@@ -209,7 +219,7 @@ 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);
+static inline void bw_one_pole_set_sticky_thresh(bw_one_pole_coeffs *restrict coeffs, float value);
 /*! <<<```
  *    Sets the target-reach threshold specified by `value` for the given
  *    `instance`.
@@ -225,15 +235,17 @@ 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);
+static inline void bw_one_pole_set_sticky_mode(bw_one_pole_coeffs *restrict coeffs, 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 {
+/*** Implementation ***/
+
+/* WARNING: This part of the file is not part of the public API. Its content may
+ * change at any time in future versions. Please, do not use it directly. */
+
+struct _bw_one_pole_coeffs {
 	// Coefficients
 	float			Ttm2pi;
 
@@ -248,13 +260,183 @@ struct _bw_one_pole {
 	float			sticky_thresh;
 	bw_one_pole_sticky_mode sticky_mode;
 	int			param_changed;
-
-	// State
-	char			first_run;
-	float			x_z1;
-	float			y_z1;
 };
 
+struct _bw_one_pole_state {
+	float	y_z1;
+};
+
+#define _BW_ONE_POLE_PARAM_CUTOFF_UP		1
+#define _BW_ONE_POLE_PARAM_CUTOFF_DOWN		(1<<1)
+#define _BW_ONE_POLE_PARAM_STICKY_THRESH	(1<<2)
+
+#include <bw_math.h>
+
+static inline void bw_one_pole_init(bw_one_pole_coeffs *restrict coeffs) {
+	coeffs->init_val = 0.f;
+	coeffs->cutoff_up = INFINITY;
+	coeffs->cutoff_down = INFINITY;
+	coeffs->sticky_thresh = 0.f;
+}
+
+static inline void bw_one_pole_set_sample_rate(bw_one_pole_coeffs *restrict coeffs, float sample_rate) {
+	coeffs->Ttm2pi = -6.283185307179586f / sample_rate;
+}
+
+static inline void bw_one_pole_reset_coeffs(bw_one_pole_coeffs *restrict coeffs) {
+	coeffs->param_changed = ~0;
+	bw_one_pole_update_coeffs_ctrl(coeffs);
+}
+
+static inline void bw_one_pole_reset_state(const bw_one_pole_coeffs *restrict coeffs, bw_one_pole_state *restrict state) {
+	state->y_z1 = coeffs->init_val;
+}
+
+static inline void bw_one_pole_update_coeffs_ctrl(bw_one_pole_coeffs *restrict coeffs) {
+	if (coeffs->param_changed) {
+		if (coeffs->param_changed & _BW_ONE_POLE_PARAM_CUTOFF_UP)
+			coeffs->mA1u = bw_expf_3(coeffs->Ttm2pi * coeffs->cutoff_up);
+		if (coeffs->param_changed & _BW_ONE_POLE_PARAM_CUTOFF_DOWN)
+			coeffs->mA1d = bw_expf_3(coeffs->Ttm2pi * coeffs->cutoff_down);
+		if (coeffs->param_changed & _BW_ONE_POLE_PARAM_STICKY_THRESH)
+			coeffs->st2 = coeffs->sticky_thresh * coeffs->sticky_thresh;
+		coeffs->param_changed = 0;
+	}
+}
+
+static inline void bw_one_pole_update_coeffs_audio(bw_one_pole_coeffs *restrict coeffs) {
+}
+
+static inline float bw_one_pole_process1(const bw_one_pole_coeffs *restrict coeffs, bw_one_pole_state *restrict state, float x) {
+	const float y = x + coeffs->mA1u * (state->y_z1 - x);
+	state->y_z1 = y;
+	return y;
+}
+
+static inline float bw_one_pole_process1_sticky_abs(const bw_one_pole_coeffs *restrict coeffs, bw_one_pole_state *restrict state, float x) {
+	float y = x + coeffs->mA1u * (state->y_z1 - x);
+	const float d = y - x;
+	if (d * d <= coeffs->st2)
+		y = x;
+	state->y_z1 = y;
+	return y;
+}
+
+static inline float bw_one_pole_process1_sticky_rel(const bw_one_pole_coeffs *restrict coeffs, bw_one_pole_state *restrict state, float x) {
+	float y = x + coeffs->mA1u * (state->y_z1 - x);
+	const float d = y - x;
+	if (d * d <= coeffs->st2 * x * x)
+		y = x;
+	state->y_z1 = y;
+	return y;
+}
+
+static inline float bw_one_pole_process1_asym(const bw_one_pole_coeffs *restrict coeffs, bw_one_pole_state *restrict state, float x) {
+	const float y = x + (x >= state->y_z1 ? coeffs->mA1u : coeffs->mA1d) * (state->y_z1 - x);
+	state->y_z1 = y;
+	return y;
+}
+
+static inline float bw_one_pole_process1_asym_sticky_abs(const bw_one_pole_coeffs *restrict coeffs, bw_one_pole_state *restrict state, float x) {
+	float y = x + (x >= state->y_z1 ? coeffs->mA1u : coeffs->mA1d) * (state->y_z1 - x);
+	const float d = y - x;
+	if (d * d <= coeffs->st2)
+		y = x;
+	state->y_z1 = y;
+	return y;
+}
+
+static inline float bw_one_pole_process1_asym_sticky_rel(const bw_one_pole_coeffs *restrict coeffs, bw_one_pole_state *restrict state, float x) {
+	float y = x + (x >= state->y_z1 ? coeffs->mA1u : coeffs->mA1d) * (state->y_z1 - x);
+	const float d = y - x;
+	if (d * d <= coeffs->st2 * x * x)
+		y = x;
+	state->y_z1 = y;
+	return y;
+}
+
+static inline void bw_one_pole_process(bw_one_pole_coeffs *restrict coeffs, bw_one_pole_state *restrict state, const float *x, float *y, int n_samples) {
+	bw_one_pole_update_coeffs_ctrl(coeffs);
+	
+	if (coeffs->mA1u != coeffs->mA1d) {
+		if (coeffs->st2 != 0.f) {
+			if (coeffs->sticky_mode == bw_one_pole_sticky_mode_abs)
+				for (int i = 0; i < n_samples; i++)
+					y[i] = bw_one_pole_process1_asym_sticky_abs(coeffs, state, x[i]);
+			else
+				for (int i = 0; i < n_samples; i++)
+					y[i] = bw_one_pole_process1_asym_sticky_rel(coeffs, state, x[i]);
+		}
+		else {
+			for (int i = 0; i < n_samples; i++)
+				y[i] = bw_one_pole_process1_asym(coeffs, state, x[i]);
+		}
+	}
+	else {
+		if (coeffs->st2 != 0.f) {
+			if (coeffs->sticky_mode == bw_one_pole_sticky_mode_abs)
+				for (int i = 0; i < n_samples; i++)
+					y[i] = bw_one_pole_process1_sticky_abs(coeffs, state, x[i]);
+			else
+				for (int i = 0; i < n_samples; i++)
+					y[i] = bw_one_pole_process1_sticky_rel(coeffs, state, x[i]);
+		}
+		else {
+			for (int i = 0; i < n_samples; i++)
+				y[i] = bw_one_pole_process1(coeffs, state, x[i]);
+		}
+	}
+}
+
+static inline void bw_one_pole_set_init_val(bw_one_pole_coeffs *restrict coeffs, float value) {
+	coeffs->init_val = value;
+}
+
+static inline void bw_one_pole_set_cutoff(bw_one_pole_coeffs *restrict coeffs, float value) {
+	bw_one_pole_set_cutoff_up(coeffs, value);
+	bw_one_pole_set_cutoff_down(coeffs, value);
+}
+
+static inline void bw_one_pole_set_cutoff_up(bw_one_pole_coeffs *restrict coeffs, float value) {
+	if (coeffs->cutoff_up != value) {
+		coeffs->cutoff_up = value;
+		coeffs->param_changed |= _BW_ONE_POLE_PARAM_CUTOFF_UP;
+	}
+}
+
+static inline void bw_one_pole_set_cutoff_down(bw_one_pole_coeffs *restrict coeffs, float value) {
+	if (coeffs->cutoff_down != value) {
+		coeffs->cutoff_down = value;
+		coeffs->param_changed |= _BW_ONE_POLE_PARAM_CUTOFF_DOWN;
+	}
+}
+
+static inline void bw_one_pole_set_tau(bw_one_pole_coeffs *restrict coeffs, float value) {
+	bw_one_pole_set_tau_up(coeffs, value);
+	bw_one_pole_set_tau_down(coeffs, value);
+}
+
+static inline void bw_one_pole_set_tau_up(bw_one_pole_coeffs *restrict coeffs, float value) {
+	bw_one_pole_set_cutoff_up(coeffs, value < 1e-9f ? INFINITY : 0.1591549430918953f * bw_rcpf_2(value));
+	// tau < 1 ns is instantaneous for any practical purpose
+}
+
+static inline void bw_one_pole_set_tau_down(bw_one_pole_coeffs *restrict coeffs, float value) {
+	bw_one_pole_set_cutoff_down(coeffs, value < 1e-9f ? INFINITY : 0.1591549430918953f * bw_rcpf_2(value));
+	// as before
+}
+
+static inline void bw_one_pole_set_sticky_thresh(bw_one_pole_coeffs *restrict coeffs, float value) {
+	if (coeffs->sticky_thresh != value) {
+		coeffs->sticky_thresh = value;
+		coeffs->param_changed |= _BW_ONE_POLE_PARAM_STICKY_THRESH;
+	}
+}
+
+static inline void bw_one_pole_set_sticky_mode(bw_one_pole_coeffs *restrict coeffs, bw_one_pole_sticky_mode value) {
+	coeffs->sticky_mode = value;
+}
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/include/bw_osc_pulse.h b/include/bw_osc_pulse.h
index 74d0f6a..75f5a40 100644
--- a/include/bw_osc_pulse.h
+++ b/include/bw_osc_pulse.h
@@ -20,7 +20,7 @@
 /*!
  *  module_type {{{ dsp }}}
  *  version {{{ 0.2.0 }}}
- *  requires {{{ bw_config bw_common bw_inline_one_pole bw_math }}}
+ *  requires {{{ bw_config bw_common bw_one_pole bw_math }}}
  *  description {{{
  *    Pulse oscillator waveshaper with variable pulse width (actually, duty
  *    cycle) and PolyBLEP antialiasing.
diff --git a/include/bw_osc_tri.h b/include/bw_osc_tri.h
index 8d58e26..e25b0e0 100644
--- a/include/bw_osc_tri.h
+++ b/include/bw_osc_tri.h
@@ -20,7 +20,7 @@
 /*!
  *  module_type {{{ dsp }}}
  *  version {{{ 0.2.0 }}}
- *  requires {{{ bw_config bw_common bw_inline_one_pole bw_math }}}
+ *  requires {{{ bw_config bw_common bw_one_pole bw_math }}}
  *  description {{{
  *    Triangle oscillator waveshaper with variable slope (increasing time over
  *    period) and PolyBLEP antialiasing.
diff --git a/include/bw_svf.h b/include/bw_svf.h
index 466566b..e194a75 100644
--- a/include/bw_svf.h
+++ b/include/bw_svf.h
@@ -20,7 +20,7 @@
 /*!
  *  module_type {{{ dsp }}}
  *  version {{{ 0.2.0 }}}
- *  requires {{{ bw_config bw_common bw_inline_one_pole bw_math }}}
+ *  requires {{{ bw_config bw_common bw_one_pole bw_math }}}
  *  description {{{
  *    State variable filter (2nd order, 12 dB/oct) model with separated lowpass,
  *    bandpass, and highpass outputs.
@@ -29,7 +29,7 @@
  *    <ul>
  *      <li>Version <strong>0.2.0</strong>:
  *        <ul>
- *          <li>Refactored API to avoid dynamic memory allocation.</li>
+ *          <li>Refactored API.</li>
  *        </ul>
  *      </li>
  *      <li>Version <strong>0.1.0</strong>:
@@ -113,13 +113,20 @@ void bw_svf_set_Q(bw_svf *instance, float value);
  *    Default value: `0.5f`.
  *  }}} */
 
+#include <bw_one_pole.h>
+
 /* 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 {
+	// Sub-components
+	bw_one_pole_coeffs	smooth_cutoff_coeffs;
+	bw_one_pole_state	smooth_cutoff_state;
+	bw_one_pole_coeffs	smooth_Q_coeffs;
+	bw_one_pole_state	smooth_Q_state;
+	
 	// Coefficients
 	float	t_k;
-	float	smooth_mA1;
 
 	float	t;
 	float	k;
diff --git a/include/bw_wah.h b/include/bw_wah.h
index eb494eb..901c290 100644
--- a/include/bw_wah.h
+++ b/include/bw_wah.h
@@ -20,7 +20,7 @@
 /*!
  *  module_type {{{ dsp }}}
  *  version {{{ 0.2.0 }}}
- *  requires {{{ bw_config bw_common bw_inline_one_pole bw_math bw_wah }}}
+ *  requires {{{ bw_config bw_common bw_one_pole bw_math bw_wah }}}
  *  description {{{
  *    Wah effect.
  *
diff --git a/src/bw_one_pole.c b/src/bw_one_pole.c
deleted file mode 100644
index 9b0d954..0000000
--- a/src/bw_one_pole.c
+++ /dev/null
@@ -1,180 +0,0 @@
-/*
- * Brickworks
- *
- * Copyright (C) 2021, 2022 Orastron Srl unipersonale
- *
- * Brickworks is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, version 3 of the License.
- *
- * Brickworks is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- *
- * File author: Stefano D'Angelo
- */
-
-#include <bw_one_pole.h>
-
-#include <bw_math.h>
-
-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_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) {
-	instance->first_run = 1;
-	instance->param_changed = ~0;
-}
-
-#define PARAM_CUTOFF_UP		1
-#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) {
-	if (instance->param_changed) {
-		if (instance->param_changed & PARAM_CUTOFF_UP)
-			instance->mA1u = bw_expf_3(instance->Ttm2pi * instance->cutoff_up);
-		if (instance->param_changed & PARAM_CUTOFF_DOWN)
-			instance->mA1d = bw_expf_3(instance->Ttm2pi * instance->cutoff_down);
-		if (instance->param_changed & PARAM_STICKY_THRESH)
-			instance->st2 = instance->sticky_thresh * instance->sticky_thresh;
-		instance->param_changed = 0;
-	}
-	
-	if (instance->first_run) {
-		instance->x_z1 = instance->init_val;
-		instance->y_z1 = instance->init_val;
-		instance->first_run = 0;
-	}
-
-	if (instance->mA1u != instance->mA1d) {
-		if (instance->st2 != 0.f) {
-			if (instance->sticky_mode == bw_one_pole_sticky_mode_abs)
-				for (int i = 0; i < n_samples; i++) {
-					const float in = x[i];
-					float out = in + (in >= instance->y_z1 ? instance->mA1u : instance->mA1d) * (instance->y_z1 - in);
-					const float d = out - in;
-					if (d * d <= instance->st2)
-						out = in;
-					instance->x_z1 = in;
-					instance->y_z1 = out;
-					y[i] = out;
-				}
-			else
-				for (int i = 0; i < n_samples; i++) {
-					const float in = x[i];
-					float out = in + (in >= instance->y_z1 ? instance->mA1u : instance->mA1d) * (instance->y_z1 - in);
-					const float d = out - in;
-					if (d * d <= instance->st2 * in * in)
-						out = in;
-					instance->x_z1 = in;
-					instance->y_z1 = out;
-					y[i] = out;
-				}
-		}
-		else {
-			for (int i = 0; i < n_samples; i++) {
-				const float in = x[i];
-				const float out = in + (in >= instance->y_z1 ? instance->mA1u : instance->mA1d) * (instance->y_z1 - in);
-				instance->x_z1 = in;
-				instance->y_z1 = out;
-				y[i] = out;
-			}
-		}
-	}
-	else {
-		if (instance->st2 != 0.f) {
-			if (instance->sticky_mode == bw_one_pole_sticky_mode_abs)
-				for (int i = 0; i < n_samples; i++) {
-					const float in = x[i];
-					float out = in + instance->mA1u * (instance->y_z1 - in);
-					const float d = out - in;
-					if (d * d <= instance->st2)
-						out = in;
-					instance->x_z1 = in;
-					instance->y_z1 = out;
-					y[i] = out;
-				}
-			else
-				for (int i = 0; i < n_samples; i++) {
-					const float in = x[i];
-					float out = in + instance->mA1u * (instance->y_z1 - in);
-					const float d = out - in;
-					if (d * d <= instance->st2 * in * in)
-						out = in;
-					instance->x_z1 = in;
-					instance->y_z1 = out;
-					y[i] = out;
-				}
-		}
-		else {
-			for (int i = 0; i < n_samples; i++) {
-				const float in = x[i];
-				const float out = in + instance->mA1u * (instance->y_z1 - in);
-				instance->x_z1 = in;
-				instance->y_z1 = out;
-				y[i] = out;
-			}
-		}
-	}
-}
-
-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) {
-	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) {
-	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) {
-	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) {
-	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) {
-	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) {
-	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) {
-	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) {
-	instance->sticky_mode = value;
-}
diff --git a/src/bw_svf.c b/src/bw_svf.c
index f78272e..ebe8ad1 100644
--- a/src/bw_svf.c
+++ b/src/bw_svf.c
@@ -20,16 +20,22 @@
 #include <bw_svf.h>
 
 #include <bw_math.h>
-#include <bw_inline_one_pole.h>
 
 void bw_svf_init(bw_svf *instance) {
+	bw_one_pole_init(&instance->smooth_cutoff_coeffs);
+	bw_one_pole_set_tau(&instance->smooth_cutoff_coeffs, 0.05f);
+	bw_one_pole_set_sticky_thresh(&instance->smooth_cutoff_coeffs, 1e-3f);
+	bw_one_pole_init(&instance->smooth_Q_coeffs);
+	bw_one_pole_set_tau(&instance->smooth_Q_coeffs, 0.05f);
+	bw_one_pole_set_sticky_thresh(&instance->smooth_Q_coeffs, 1e-3f);
 	instance->cutoff = 1e3f;
 	instance->Q = 0.5f;
 }
 
 void bw_svf_set_sample_rate(bw_svf *instance, float sample_rate) {
+	bw_one_pole_set_sample_rate(&instance->smooth_cutoff_coeffs, sample_rate);
+	bw_one_pole_set_sample_rate(&instance->smooth_Q_coeffs, 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) {
@@ -40,15 +46,17 @@ void bw_svf_reset(bw_svf *instance) {
 #define PARAM_Q		(1<<1)
 
 static inline void update_coefficients(bw_svf *instance) {
+	bw_one_pole_update_coeffs_audio(&instance->smooth_cutoff_coeffs);
+	bw_one_pole_update_coeffs_audio(&instance->smooth_Q_coeffs);
 	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) {
 		if (cutoff_changed) {
-			instance->cutoff_cur = bw_inline_one_pole_sticky_rel(instance->cutoff, instance->cutoff_cur, instance->smooth_mA1, 1e-6f);
+			instance->cutoff_cur = bw_one_pole_process1_sticky_rel(&instance->smooth_cutoff_coeffs, &instance->smooth_cutoff_state, instance->cutoff);
 			instance->t = bw_tanf_3(instance->t_k * instance->cutoff_cur);
 		}
 		if (Q_changed) {
-			instance->Q_cur = bw_inline_one_pole_sticky_abs(instance->Q, instance->Q_cur, instance->smooth_mA1, 1e-6f);
+			instance->Q_cur = bw_one_pole_process1_sticky_abs(&instance->smooth_Q_coeffs, &instance->smooth_Q_state, instance->Q);
 			instance->k = bw_rcpf_2(instance->Q_cur);
 		}
 		const float kpt = instance->k + instance->t;
@@ -60,14 +68,21 @@ 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) {
 	if (instance->first_run) {
-		instance->cutoff_cur = instance->cutoff;
-		instance->Q_cur = instance->Q;
+		bw_one_pole_set_init_val(&instance->smooth_cutoff_coeffs, instance->cutoff);
+		bw_one_pole_reset_coeffs(&instance->smooth_cutoff_coeffs);
+		bw_one_pole_reset_state(&instance->smooth_cutoff_coeffs, &instance->smooth_cutoff_state);
+		bw_one_pole_set_init_val(&instance->smooth_Q_coeffs, instance->Q);
+		bw_one_pole_reset_coeffs(&instance->smooth_Q_coeffs);
+		bw_one_pole_reset_state(&instance->smooth_Q_coeffs, &instance->smooth_Q_state);
 		update_coefficients(instance);
 		instance->hp_z1 = 0.f;
 		instance->lp_z1 = 0.f;
 		instance->bp_z1 = 0.f;
 		instance->first_run = 0;
 	}
+	
+	bw_one_pole_update_coeffs_ctrl(&instance->smooth_cutoff_coeffs);
+	bw_one_pole_update_coeffs_ctrl(&instance->smooth_Q_coeffs);
 
 	for (int i = 0; i < n_samples; i++) {
 		update_coefficients(instance);