diff --git a/TODO b/TODO
index 2abe9da..34784b9 100644
--- a/TODO
+++ b/TODO
@@ -27,7 +27,6 @@ code:
 * mem req -> return value of set sample rate?
 * peak gain + Q ???
 * sr_reduce reset_coeffs? update_coeffs? process_multi?
-* allow nullptr in C++ wrappers where process_multi arg can be NULL
 * better src filter
 * c++ get coeffs/state? or public? src nIn/OutSamples case (array vs single value), delay read/write, process1? process single?
 * check unititialized warnings (check fxpp_comp in particular vs fxpp_satur)
diff --git a/examples/synthpp_poly/src/bw_example_synthpp_poly.cpp b/examples/synthpp_poly/src/bw_example_synthpp_poly.cpp
index 10bce77..7ad5c26 100644
--- a/examples/synthpp_poly/src/bw_example_synthpp_poly.cpp
+++ b/examples/synthpp_poly/src/bw_example_synthpp_poly.cpp
@@ -167,7 +167,7 @@ void bw_example_synthpp_poly_process(bw_example_synthpp_poly *instance, const fl
 
 	const float vcf_mod_k = 0.3f * instance->params[p_vcf_mod];
 
-	float *b0[N_VOICES], *b1[N_VOICES], *b2[N_VOICES], *b3[N_VOICES], *b4[N_VOICES], *na[N_VOICES];
+	float *b0[N_VOICES], *b1[N_VOICES], *b2[N_VOICES], *b3[N_VOICES], *b4[N_VOICES];
 	char xgates[N_VOICES];
 	for (int j = 0; j < N_VOICES; j++) {
 		b0[j] = instance->voices[j].buf[0];
@@ -175,7 +175,6 @@ void bw_example_synthpp_poly_process(bw_example_synthpp_poly *instance, const fl
 		b2[j] = instance->voices[j].buf[2];
 		b3[j] = instance->voices[j].buf[3];
 		b4[j] = instance->voices[j].buf[4];
-		na[j] = nullptr;
 		xgates[j] = instance->voices[j].gate;
 	}
 
@@ -258,7 +257,7 @@ void bw_example_synthpp_poly_process(bw_example_synthpp_poly *instance, const fl
 		bufScale<N_VOICES>(b1, k, b1, n);
 		bufMix<N_VOICES>(b0, b1, b0, n);
 
-		instance->vcfEnvGen.process(xgates, na, n);
+		instance->vcfEnvGen.process(xgates, {}, n);
 		for (int j = 0; j < N_VOICES; j++) {
 			float v = instance->params[p_vcf_cutoff] + instance->params[p_vcf_contour] * instance->vcfEnvGen.getYZ1(j) + vcf_mod[j];
 			float cutoff = 20.f + (20e3f - 20.f) * v * v * v;
diff --git a/include/bw_buf.h b/include/bw_buf.h
index d2e307c..950d28a 100644
--- a/include/bw_buf.h
+++ b/include/bw_buf.h
@@ -38,6 +38,8 @@
  *          <li>Added overladed C++ functions taking C-style arrays as
  *              arguments.</li>
  *          <li>Removed usage of reserved identifiers.</li>
+ *          <li>Now enforcing that buffers are never <code>NULL</code> in
+ *              debugging code.</li>
  *        </ul>
  *      </li>
  *      <li>Version <strong>0.6.0</strong>:
@@ -183,8 +185,8 @@ extern "C" {
 #endif
 
 static inline void bw_buf_fill(float k, float *BW_RESTRICT dest, size_t n_elems) {
-	BW_ASSERT(!(dest == NULL && n_elems != 0));
 	BW_ASSERT(!bw_is_nan(k));
+	BW_ASSERT(dest != NULL);
 
 	for (size_t i = 0; i < n_elems; i++)
 		dest[i] = k;
@@ -193,8 +195,9 @@ static inline void bw_buf_fill(float k, float *BW_RESTRICT dest, size_t n_elems)
 }
 
 static inline void bw_buf_neg(const float *src, float *dest, size_t n_elems) {
-	BW_ASSERT(!((dest == NULL || src == NULL) && n_elems != 0));
+	BW_ASSERT(src != NULL);
 	BW_ASSERT_DEEP(!bw_has_nan(src, n_elems));
+	BW_ASSERT(dest != NULL);
 
 	for (size_t i = 0; i < n_elems; i++)
 		dest[i] = -src[i];
@@ -203,9 +206,10 @@ static inline void bw_buf_neg(const float *src, float *dest, size_t n_elems) {
 }
 
 static inline void bw_buf_add(const float *src, float k, float *dest, size_t n_elems) {
-	BW_ASSERT(!((dest == NULL || src == NULL) && n_elems != 0));
+	BW_ASSERT(src != NULL);
 	BW_ASSERT_DEEP(!bw_has_nan(src, n_elems));
 	BW_ASSERT(!bw_is_nan(k));
+	BW_ASSERT(dest != NULL);
 
 	for (size_t i = 0; i < n_elems; i++)
 		dest[i] = k + src[i];
@@ -214,9 +218,10 @@ static inline void bw_buf_add(const float *src, float k, float *dest, size_t n_e
 }
 
 static inline void bw_buf_scale(const float *src, float k, float *dest, size_t n_elems) {
-	BW_ASSERT(!((dest == NULL || src == NULL) && n_elems != 0));
+	BW_ASSERT(src != NULL);
 	BW_ASSERT_DEEP(!bw_has_nan(src, n_elems));
 	BW_ASSERT(!bw_is_nan(k));
+	BW_ASSERT(dest != NULL);
 
 	for (size_t i = 0; i < n_elems; i++)
 		dest[i] = k * src[i];
@@ -225,9 +230,11 @@ static inline void bw_buf_scale(const float *src, float k, float *dest, size_t n
 }
 
 static inline void bw_buf_mix(const float *src1, const float *src2, float *dest, size_t n_elems) {
-	BW_ASSERT(!((dest == NULL || src1 == NULL || src2 == NULL) && n_elems != 0));
+	BW_ASSERT(src1 != NULL);
 	BW_ASSERT_DEEP(!bw_has_nan(src1, n_elems));
+	BW_ASSERT(src2 != NULL);
 	BW_ASSERT_DEEP(!bw_has_nan(src2, n_elems));
+	BW_ASSERT(dest != NULL);
 
 	for (size_t i = 0; i < n_elems; i++)
 		dest[i] = src1[i] + src2[i];
@@ -236,9 +243,11 @@ static inline void bw_buf_mix(const float *src1, const float *src2, float *dest,
 }
 
 static inline void bw_buf_mul(const float *src1, const float *src2, float *dest, size_t n_elems) {
-	BW_ASSERT(!((dest == NULL || src1 == NULL || src2 == NULL) && n_elems != 0));
+	BW_ASSERT(src1 != NULL);
 	BW_ASSERT_DEEP(!bw_has_nan(src1, n_elems));
+	BW_ASSERT(src2 != NULL);
 	BW_ASSERT_DEEP(!bw_has_nan(src2, n_elems));
+	BW_ASSERT(dest != NULL);
 
 	for (size_t i = 0; i < n_elems; i++)
 		dest[i] = src1[i] * src2[i];
@@ -247,42 +256,52 @@ static inline void bw_buf_mul(const float *src1, const float *src2, float *dest,
 }
 
 static inline void bw_buf_fill_multi(float k, float *BW_RESTRICT const *BW_RESTRICT dest, size_t n_channels, size_t n_elems) {
-	BW_ASSERT(!(dest == NULL && n_channels != 0));
+	BW_ASSERT(!bw_is_nan(k));
+	BW_ASSERT(dest != NULL);
 
 	for (size_t i = 0; i < n_channels; i++)
 		bw_buf_fill(k, dest[i], n_elems);
 }
 
 static inline void bw_buf_neg_multi(const float * const *src, float * const *dest, size_t n_channels, size_t n_elems) {
-	BW_ASSERT(!((dest == NULL || src == NULL) && n_channels != 0));
+	BW_ASSERT(src != NULL);
+	BW_ASSERT(dest != NULL);
 
 	for (size_t i = 0; i < n_channels; i++)
 		bw_buf_neg(src[i], dest[i], n_elems);
 }
 
 static inline void bw_buf_add_multi(const float * const *src, float k, float * const *dest, size_t n_channels, size_t n_elems) {
-	BW_ASSERT(!((dest == NULL || src == NULL) && n_channels != 0));
+	BW_ASSERT(src != NULL);
+	BW_ASSERT(!bw_is_nan(k));
+	BW_ASSERT(dest != NULL);
 
 	for (size_t i = 0; i < n_channels; i++)
 		bw_buf_add(src[i], k, dest[i], n_elems);
 }
 
 static inline void bw_buf_scale_multi(const float * const *src, float k, float * const *dest, size_t n_channels, size_t n_elems) {
-	BW_ASSERT(!((dest == NULL || src == NULL) && n_channels != 0));
+	BW_ASSERT(src != NULL);
+	BW_ASSERT(!bw_is_nan(k));
+	BW_ASSERT(dest != NULL);
 
 	for (size_t i = 0; i < n_channels; i++)
 		bw_buf_scale(src[i], k, dest[i], n_elems);
 }
 
 static inline void bw_buf_mix_multi(const float * const *src1, const float * const *src2, float * const *dest, size_t n_channels, size_t n_elems) {
-	BW_ASSERT(!((dest == NULL || src1 == NULL || src2 == NULL) && n_channels != 0));
+	BW_ASSERT(src1 != NULL);
+	BW_ASSERT(src2 != NULL);
+	BW_ASSERT(dest != NULL);
 
 	for (size_t i = 0; i < n_channels; i++)
 		bw_buf_mix(src1[i], src2[i], dest[i], n_elems);
 }
 
 static inline void bw_buf_mul_multi(const float * const *src1, const float * const *src2, float * const *dest, size_t n_channels, size_t n_elems) {
-	BW_ASSERT(!((dest == NULL || src1 == NULL || src2 == NULL) && n_channels != 0));
+	BW_ASSERT(src1 != NULL);
+	BW_ASSERT(src2 != NULL);
+	BW_ASSERT(dest != NULL);
 
 	for (size_t i = 0; i < n_channels; i++)
 		bw_buf_mul(src1[i], src2[i], dest[i], n_elems);