diff --git a/include/bw_noise_gate.h b/include/bw_noise_gate.h
index ea65d61..84c24bd 100644
--- a/include/bw_noise_gate.h
+++ b/include/bw_noise_gate.h
@@ -29,6 +29,8 @@
  *    <ul>
  *      <li>Version <strong>1.1.1</strong>:
  *        <ul>
+ *          <li>Added debugging checks from <code>bw_noise_gate_process()</code>
+ *              to <code>bw_noise_gate_process_multi()</code>.</li>
  *          <li>Added debugging checks in
  *              <code>bw_noise_gate_process_multi()</code> to ensure that
  *              buffers used for both input and output appear at the same
@@ -616,6 +618,10 @@ static inline void bw_noise_gate_process_multi(
 	BW_ASSERT_DEEP(coeffs->state >= bw_noise_gate_coeffs_state_reset_coeffs);
 	BW_ASSERT(state != BW_NULL);
 #ifndef BW_NO_DEBUG
+	for (size_t i = 0; i < n_channels; i++) {
+		BW_ASSERT(state[i] != BW_NULL);
+		BW_ASSERT_DEEP(bw_noise_gate_state_is_valid(coeffs, state[i]));
+	}
 	for (size_t i = 0; i < n_channels; i++)
 		for (size_t j = i + 1; j < n_channels; j++)
 			BW_ASSERT(state[i] != state[j]);
@@ -623,6 +629,12 @@ static inline void bw_noise_gate_process_multi(
 	BW_ASSERT(x != BW_NULL);
 	BW_ASSERT(y != BW_NULL);
 #ifndef BW_NO_DEBUG
+	for (size_t i = 0; i < n_channels; i++) {
+		BW_ASSERT(x[i] != BW_NULL);
+		BW_ASSERT_DEEP(bw_has_only_finite(x[i], n_samples));
+		BW_ASSERT_DEEP(x_sc != BW_NULL && x_sc[i] != BW_NULL ? bw_has_only_finite(x_sc[i], n_samples) : 1);
+		BW_ASSERT(y[i] != BW_NULL);
+	}
 	for (size_t i = 0; i < n_channels; i++)
 		for (size_t j = i + 1; j < n_channels; j++)
 			BW_ASSERT(y[i] != y[j]);
@@ -651,6 +663,12 @@ static inline void bw_noise_gate_process_multi(
 
 	BW_ASSERT_DEEP(bw_noise_gate_coeffs_is_valid(coeffs));
 	BW_ASSERT_DEEP(coeffs->state >= bw_noise_gate_coeffs_state_reset_coeffs);
+#ifndef BW_NO_DEBUG
+	for (size_t i = 0; i < n_channels; i++) {
+		BW_ASSERT_DEEP(bw_noise_gate_state_is_valid(coeffs, state[i]));
+		BW_ASSERT_DEEP(bw_has_only_finite(y[i], n_samples));
+	}
+#endif
 }
 
 static inline void bw_noise_gate_set_thresh_lin(
diff --git a/include/bw_notch.h b/include/bw_notch.h
index 35ecafb..e0a4f9f 100644
--- a/include/bw_notch.h
+++ b/include/bw_notch.h
@@ -30,6 +30,8 @@
  *    <ul>
  *      <li>Version <strong>1.1.1</strong>:
  *        <ul>
+ *          <li>Added debugging checks from <code>bw_notch_process()</code> to
+ *              <code>bw_notch_process_multi()</code>.</li>
  *          <li>Added debugging checks in <code>bw_notch_process_multi()</code>
  *              to ensure that buffers used for both input and output appear at
  *              the same channel indices.</li>
@@ -526,6 +528,10 @@ static inline void bw_notch_process_multi(
 	BW_ASSERT_DEEP(coeffs->state >= bw_notch_coeffs_state_reset_coeffs);
 	BW_ASSERT(state != BW_NULL);
 #ifndef BW_NO_DEBUG
+	for (size_t i = 0; i < n_channels; i++) {
+		BW_ASSERT(state[i] != BW_NULL);
+		BW_ASSERT_DEEP(bw_notch_state_is_valid(coeffs, state[i]));
+	}
 	for (size_t i = 0; i < n_channels; i++)
 		for (size_t j = i + 1; j < n_channels; j++)
 			BW_ASSERT(state[i] != state[j]);
@@ -533,6 +539,11 @@ static inline void bw_notch_process_multi(
 	BW_ASSERT(x != BW_NULL);
 	BW_ASSERT(y != BW_NULL);
 #ifndef BW_NO_DEBUG
+	for (size_t i = 0; i < n_channels; i++) {
+		BW_ASSERT(x[i] != BW_NULL);
+		BW_ASSERT_DEEP(bw_has_only_finite(x[i], n_samples));
+		BW_ASSERT(y[i] != BW_NULL);
+	}
 	for (size_t i = 0; i < n_channels; i++)
 		for (size_t j = i + 1; j < n_channels; j++)
 			BW_ASSERT(y[i] != y[j]);
@@ -550,6 +561,12 @@ static inline void bw_notch_process_multi(
 
 	BW_ASSERT_DEEP(bw_notch_coeffs_is_valid(coeffs));
 	BW_ASSERT_DEEP(coeffs->state >= bw_notch_coeffs_state_reset_coeffs);
+#ifndef BW_NO_DEBUG
+	for (size_t i = 0; i < n_channels; i++) {
+		BW_ASSERT_DEEP(bw_notch_state_is_valid(coeffs, state[i]));
+		BW_ASSERT_DEEP(bw_has_only_finite(y[i], n_samples));
+	}
+#endif
 }
 
 static inline void bw_notch_set_cutoff(
diff --git a/include/bw_one_pole.h b/include/bw_one_pole.h
index f781808..0fc05ee 100644
--- a/include/bw_one_pole.h
+++ b/include/bw_one_pole.h
@@ -32,6 +32,8 @@
  *    <ul>
  *      <li>Version <strong>1.1.1</strong>:
  *        <ul>
+ *          <li>Added debugging checks from <code>bw_one_pole_process()</code>
+ *              to <code>bw_one_pole_process_multi()</code>.</li>
  *          <li>Added debugging checks in
  *              <code>bw_one_pole_process_multi()</code> to ensure that buffers
  *              used for both input and output appear at the same channel
@@ -903,12 +905,20 @@ static inline void bw_one_pole_process_multi(
 	BW_ASSERT_DEEP(coeffs->state >= bw_one_pole_coeffs_state_reset_coeffs);
 	BW_ASSERT(state != BW_NULL);
 #ifndef BW_NO_DEBUG
+	for (size_t i = 0; i < n_channels; i++) {
+		BW_ASSERT(state[i] != BW_NULL);
+		BW_ASSERT_DEEP(bw_one_pole_state_is_valid(coeffs, state[i]));
+	}
 	for (size_t i = 0; i < n_channels; i++)
 		for (size_t j = i + 1; j < n_channels; j++)
 			BW_ASSERT(state[i] != state[j]);
 #endif
 	BW_ASSERT(x != BW_NULL);
 #ifndef BW_NO_DEBUG
+	for (size_t i = 0; i < n_channels; i++) {
+		BW_ASSERT(x[i] != BW_NULL);
+		BW_ASSERT_DEEP(bw_has_only_finite(x[i], n_samples));
+	}
 	if (y != BW_NULL) {
 		for (size_t i = 0; i < n_channels; i++)
 			for (size_t j = i + 1; j < n_channels; j++)
@@ -1019,6 +1029,12 @@ static inline void bw_one_pole_process_multi(
 
 	BW_ASSERT_DEEP(bw_one_pole_coeffs_is_valid(coeffs));
 	BW_ASSERT_DEEP(coeffs->state >= bw_one_pole_coeffs_state_reset_coeffs);
+#ifndef BW_NO_DEBUG
+	for (size_t i = 0; i < n_channels; i++) {
+		BW_ASSERT_DEEP(bw_one_pole_state_is_valid(coeffs, state[i]));
+		BW_ASSERT_DEEP(y != BW_NULL && y[i] != BW_NULL ? bw_has_only_finite(y[i], n_samples) : 1);
+	}
+#endif
 }
 
 static inline void bw_one_pole_set_cutoff(
diff --git a/include/bw_osc_pulse.h b/include/bw_osc_pulse.h
index 5b06077..ea8d608 100644
--- a/include/bw_osc_pulse.h
+++ b/include/bw_osc_pulse.h
@@ -39,6 +39,8 @@
  *    <ul>
  *      <li>Version <strong>1.1.1</strong>:
  *        <ul>
+ *          <li>Added debugging checks from <code>bw_osc_pulse_process()</code>
+ *              to <code>bw_osc_pulse_process_multi()</code>.</li>
  *          <li>Added debugging checks in
  *              <code>bw_osc_pulse_process_multi()</code> to ensure that
  *              <code>x_inc</code> is not <code>BW_NULL</code> when antialiasing
@@ -482,6 +484,13 @@ static inline void bw_osc_pulse_process_multi(
 	BW_ASSERT(coeffs->antialiasing ? x_inc != BW_NULL : 1);
 	BW_ASSERT(y != BW_NULL);
 #ifndef BW_NO_DEBUG
+	for (size_t i = 0; i < n_channels; i++) {
+		BW_ASSERT(x[i] != BW_NULL);
+		BW_ASSERT_DEEP(bw_has_only_finite(x[i], n_samples));
+		BW_ASSERT(coeffs->antialiasing ? x_inc[i] != BW_NULL : 1);
+		BW_ASSERT_DEEP(coeffs->antialiasing ? bw_has_only_finite(x_inc[i], n_samples) : 1);
+		BW_ASSERT(y[i] != BW_NULL);
+	}
 	for (size_t i = 0; i < n_channels; i++)
 		for (size_t j = i + 1; j < n_channels; j++)
 			BW_ASSERT(y[i] != y[j]);
@@ -509,6 +518,10 @@ static inline void bw_osc_pulse_process_multi(
 
 	BW_ASSERT_DEEP(bw_osc_pulse_coeffs_is_valid(coeffs));
 	BW_ASSERT_DEEP(coeffs->state >= bw_osc_pulse_coeffs_state_reset_coeffs);
+#ifndef BW_NO_DEBUG
+	for (size_t i = 0; i < n_channels; i++)
+		BW_ASSERT_DEEP(bw_has_only_finite(y[i], n_samples));
+#endif
 }
 
 static inline void bw_osc_pulse_set_antialiasing(
diff --git a/include/bw_osc_tri.h b/include/bw_osc_tri.h
index c4e2854..f16aee6 100644
--- a/include/bw_osc_tri.h
+++ b/include/bw_osc_tri.h
@@ -39,6 +39,8 @@
  *    <ul>
  *      <li>Version <strong>1.1.1</strong>:
  *        <ul>
+ *          <li>Added debugging checks from <code>bw_osc_tri_process()</code> to
+ *              <code>bw_osc_tri_process_multi()</code>.</li>
  *          <li>Added debugging checks in
  *              <code>bw_osc_tri_process_multi()</code> to ensure that
  *              <code>x_inc</code> is not <code>BW_NULL</code> when antialiasing
@@ -489,6 +491,13 @@ static inline void bw_osc_tri_process_multi(
 	BW_ASSERT(coeffs->antialiasing ? x_inc != BW_NULL : 1);
 	BW_ASSERT(y != BW_NULL);
 #ifndef BW_NO_DEBUG
+	for (size_t i = 0; i < n_channels; i++) {
+		BW_ASSERT(x[i] != BW_NULL);
+		BW_ASSERT_DEEP(bw_has_only_finite(x[i], n_samples));
+		BW_ASSERT(coeffs->antialiasing ? x_inc[i] != BW_NULL : 1);
+		BW_ASSERT_DEEP(coeffs->antialiasing ? bw_has_only_finite(x_inc[i], n_samples) : 1);
+		BW_ASSERT(y[i] != BW_NULL);
+	}
 	for (size_t i = 0; i < n_channels; i++)
 		for (size_t j = i + 1; j < n_channels; j++)
 			BW_ASSERT(y[i] != y[j]);
@@ -516,6 +525,10 @@ static inline void bw_osc_tri_process_multi(
 
 	BW_ASSERT_DEEP(bw_osc_tri_coeffs_is_valid(coeffs));
 	BW_ASSERT_DEEP(coeffs->state >= bw_osc_tri_coeffs_state_reset_coeffs);
+#ifndef BW_NO_DEBUG
+	for (size_t i = 0; i < n_channels; i++)
+		BW_ASSERT_DEEP(bw_has_only_finite(y[i], n_samples));
+#endif
 }
 
 static inline void bw_osc_tri_set_antialiasing(
diff --git a/include/bw_pan.h b/include/bw_pan.h
index a6dd3ad..60dc11e 100644
--- a/include/bw_pan.h
+++ b/include/bw_pan.h
@@ -29,6 +29,8 @@
  *    <ul>
  *      <li>Version <strong>1.1.1</strong>:
  *        <ul>
+ *          <li>Added debugging checks from <code>bw_pan_process()</code> to
+ *              <code>bw_pan_process_multi()</code>.</li>
  *          <li>Added debugging checks in <code>bw_pan_process_multi()</code> to
  *              ensure that buffers used for both input and output appear at the
  *              same channel indices.</li>
@@ -389,6 +391,13 @@ static inline void bw_pan_process_multi(
 	BW_ASSERT(y_r != BW_NULL);
 	BW_ASSERT(y_l != y_r);
 #ifndef BW_NO_DEBUG
+	for (size_t i = 0; i < n_channels; i++) {
+		BW_ASSERT(x[i] != BW_NULL);
+		BW_ASSERT_DEEP(bw_has_only_finite(x[i], n_samples));
+		BW_ASSERT(y_l[i] != BW_NULL);
+		BW_ASSERT(y_r[i] != BW_NULL);
+		BW_ASSERT(y_l[i] != y_r[i]);
+	}
 	for (size_t i = 0; i < n_channels; i++)
 		for (size_t j = i + 1; j < n_channels; j++) {
 			BW_ASSERT(y_l[i] != y_l[j]);
@@ -413,6 +422,12 @@ static inline void bw_pan_process_multi(
 
 	BW_ASSERT_DEEP(bw_pan_coeffs_is_valid(coeffs));
 	BW_ASSERT_DEEP(coeffs->state >= bw_pan_coeffs_state_reset_coeffs);
+#ifndef BW_NO_DEBUG
+	for (size_t i = 0; i < n_channels; i++) {
+		BW_ASSERT_DEEP(bw_has_only_finite(y_l[i], n_samples));
+		BW_ASSERT_DEEP(bw_has_only_finite(y_r[i], n_samples));
+	}
+#endif
 }
 
 static inline void bw_pan_set_pan(
diff --git a/include/bw_peak.h b/include/bw_peak.h
index 9f3d6c7..a276128 100644
--- a/include/bw_peak.h
+++ b/include/bw_peak.h
@@ -37,6 +37,8 @@
  *    <ul>
  *      <li>Version <strong>1.1.1</strong>:
  *        <ul>
+ *          <li>Added debugging checks from <code>bw_peak_process()</code> to
+ *              <code>bw_peak_process_multi()</code>.</li>
  *          <li>Added debugging checks in <code>bw_peak_process_multi()</code>
  *              to ensure that buffers used for both input and output appear at
  *              the same channel indices.</li>
@@ -675,6 +677,10 @@ static inline void bw_peak_process_multi(
 		: 1);
 	BW_ASSERT(state != BW_NULL);
 #ifndef BW_NO_DEBUG
+	for (size_t i = 0; i < n_channels; i++) {
+		BW_ASSERT(state[i] != BW_NULL);
+		BW_ASSERT_DEEP(bw_peak_state_is_valid(coeffs, state[i]));
+	}
 	for (size_t i = 0; i < n_channels; i++)
 		for (size_t j = i + 1; j < n_channels; j++)
 			BW_ASSERT(state[i] != state[j]);
@@ -682,6 +688,11 @@ static inline void bw_peak_process_multi(
 	BW_ASSERT(x != BW_NULL);
 	BW_ASSERT(y != BW_NULL);
 #ifndef BW_NO_DEBUG
+	for (size_t i = 0; i < n_channels; i++) {
+		BW_ASSERT(x[i] != BW_NULL);
+		BW_ASSERT_DEEP(bw_has_only_finite(x[i], n_samples));
+		BW_ASSERT(y[i] != BW_NULL);
+	}
 	for (size_t i = 0; i < n_channels; i++)
 		for (size_t j = i + 1; j < n_channels; j++)
 			BW_ASSERT(y[i] != y[j]);
@@ -699,6 +710,12 @@ static inline void bw_peak_process_multi(
 
 	BW_ASSERT_DEEP(bw_peak_coeffs_is_valid(coeffs));
 	BW_ASSERT_DEEP(coeffs->state >= bw_peak_coeffs_state_reset_coeffs);
+#ifndef BW_NO_DEBUG
+	for (size_t i = 0; i < n_channels; i++) {
+		BW_ASSERT_DEEP(bw_peak_state_is_valid(coeffs, state[i]));
+		BW_ASSERT_DEEP(bw_has_only_finite(y[i], n_samples));
+	}
+#endif
 }
 
 static inline void bw_peak_set_cutoff(
diff --git a/include/bw_phase_gen.h b/include/bw_phase_gen.h
index 2328e47..1b79b7f 100644
--- a/include/bw_phase_gen.h
+++ b/include/bw_phase_gen.h
@@ -33,6 +33,8 @@
  *        <ul>
  *          <li>Added phase_inc_min and phase_inc_max parameters.</li>
  *          <li>Fixed rounding bug when frequency is tiny (again).</li>
+ *          <li>Added debugging checks from <code>bw_phase_gen_process()</code>
+ *              to <code>bw_phase_gen_process_multi()</code>.</li>
  *          <li>Added debugging check in <code>bw_phase_reset_state()</code> to
  *              ensure that <code>phase_0</code> is in [<code>0.f</code>,
  *              <code>1.f</code>) and indicated such range in the
@@ -756,9 +758,16 @@ static inline void bw_phase_gen_process_multi(
 	BW_ASSERT_DEEP(coeffs->phase_inc_min < coeffs->phase_inc_max);
 	BW_ASSERT(state != BW_NULL);
 #ifndef BW_NO_DEBUG
+	for (size_t i = 0; i < n_channels; i++) {
+		BW_ASSERT(state[i] != BW_NULL);
+		BW_ASSERT_DEEP(bw_phase_gen_state_is_valid(coeffs, state[i]));
+	}
 	for (size_t i = 0; i < n_channels; i++)
 		for (size_t j = i + 1; j < n_channels; j++)
 			BW_ASSERT(state[i] != state[j]);
+	if (x_mod != BW_NULL)
+		for (size_t i = 0; i < n_channels; i++)
+			BW_ASSERT_DEEP(x_mod[i] != BW_NULL ? bw_has_only_finite(x_mod[i], n_samples) : 1);
 	if (y != BW_NULL)
 		for (size_t i = 0; i < n_channels; i++)
 			for (size_t j = i + 1; j < n_channels; j++)
@@ -888,6 +897,13 @@ static inline void bw_phase_gen_process_multi(
 
 	BW_ASSERT_DEEP(bw_phase_gen_coeffs_is_valid(coeffs));
 	BW_ASSERT_DEEP(coeffs->state >= bw_phase_gen_coeffs_state_reset_coeffs);
+#ifndef BW_NO_DEBUG
+	for (size_t i = 0; i < n_channels; i++) {
+		BW_ASSERT_DEEP(bw_phase_gen_state_is_valid(coeffs, state[i]));
+		BW_ASSERT_DEEP(y != BW_NULL && y[i] != BW_NULL ? bw_has_only_finite(y[i], n_samples) : 1);
+		BW_ASSERT_DEEP(y_inc != BW_NULL && y_inc[i] != BW_NULL ? bw_has_only_finite(y_inc[i], n_samples) : 1);
+	}
+#endif
 }
 
 static inline void bw_phase_gen_set_frequency(