diff --git a/spa/plugins/audiomixer/mix-ops-avx.c b/spa/plugins/audiomixer/mix-ops-avx.c
index d6b3dca5d..2ba1db85e 100644
--- a/spa/plugins/audiomixer/mix-ops-avx.c
+++ b/spa/plugins/audiomixer/mix-ops-avx.c
@@ -124,12 +124,12 @@ mix_f32_avx(struct mix_ops *ops, void * SPA_RESTRICT dst, const void * SPA_RESTR
 	uint32_t i;
 
 	if (n_src == 0)
-		memset(dst, 0, n_samples * sizeof(float));
+		memset(dst, 0, n_samples * ops->n_channels * sizeof(float));
 	else if (dst != src[0])
-		memcpy(dst, src[0], n_samples * sizeof(float));
+		memcpy(dst, src[0], n_samples * ops->n_channels * sizeof(float));
 
 	for (i = 1; i + 2 < n_src; i += 3)
 		mix_4(dst, src[i], src[i + 1], src[i + 2], n_samples);
 	for (; i < n_src; i++)
-		mix_2(dst, src[i], n_samples);
+		mix_2(dst, src[i], n_samples * ops->n_channels);
 }
diff --git a/spa/plugins/audiomixer/mix-ops-sse.c b/spa/plugins/audiomixer/mix-ops-sse.c
index 5db17605e..6e2b32465 100644
--- a/spa/plugins/audiomixer/mix-ops-sse.c
+++ b/spa/plugins/audiomixer/mix-ops-sse.c
@@ -79,11 +79,11 @@ mix_f32_sse(struct mix_ops *ops, void * SPA_RESTRICT dst, const void * SPA_RESTR
 	uint32_t i;
 
 	if (n_src == 0)
-		memset(dst, 0, n_samples * sizeof(float));
+		memset(dst, 0, n_samples * ops->n_channels * sizeof(float));
 	else if (dst != src[0])
-		memcpy(dst, src[0], n_samples * sizeof(float));
+		memcpy(dst, src[0], n_samples * ops->n_channels * sizeof(float));
 
 	for (i = 1; i < n_src; i++) {
-		mix_2(dst, src[i], n_samples);
+		mix_2(dst, src[i], n_samples * ops->n_channels);
 	}
 }
diff --git a/spa/plugins/audiomixer/mix-ops-sse2.c b/spa/plugins/audiomixer/mix-ops-sse2.c
index d24ddd093..0d76eb17d 100644
--- a/spa/plugins/audiomixer/mix-ops-sse2.c
+++ b/spa/plugins/audiomixer/mix-ops-sse2.c
@@ -79,11 +79,11 @@ mix_f64_sse2(struct mix_ops *ops, void * SPA_RESTRICT dst, const void * SPA_REST
 	uint32_t i;
 
 	if (n_src == 0)
-		memset(dst, 0, n_samples * sizeof(double));
+		memset(dst, 0, n_samples * ops->n_channels * sizeof(double));
 	else if (dst != src[0])
-		memcpy(dst, src[0], n_samples * sizeof(double));
+		memcpy(dst, src[0], n_samples * ops->n_channels * sizeof(double));
 
 	for (i = 1; i < n_src; i++) {
-		mix_2(dst, src[i], n_samples);
+		mix_2(dst, src[i], n_samples * ops->n_channels);
 	}
 }
diff --git a/spa/plugins/audiomixer/mix-ops.c b/spa/plugins/audiomixer/mix-ops.c
index f5fc697ec..816f44d1e 100644
--- a/spa/plugins/audiomixer/mix-ops.c
+++ b/spa/plugins/audiomixer/mix-ops.c
@@ -47,20 +47,20 @@ static struct mix_info mix_table[] =
 {
 	/* f32 */
 #if defined(HAVE_AVX)
-	{ SPA_AUDIO_FORMAT_F32, 1, SPA_CPU_FLAG_AVX, 4, mix_f32_avx },
-	{ SPA_AUDIO_FORMAT_F32P, 1, SPA_CPU_FLAG_AVX, 4, mix_f32_avx },
+	{ SPA_AUDIO_FORMAT_F32, 0, SPA_CPU_FLAG_AVX, 4, mix_f32_avx },
+	{ SPA_AUDIO_FORMAT_F32P, 0, SPA_CPU_FLAG_AVX, 4, mix_f32_avx },
 #endif
 #if defined (HAVE_SSE)
-	{ SPA_AUDIO_FORMAT_F32, 1, SPA_CPU_FLAG_SSE, 4, mix_f32_sse },
-	{ SPA_AUDIO_FORMAT_F32P, 1, SPA_CPU_FLAG_SSE, 4, mix_f32_sse },
+	{ SPA_AUDIO_FORMAT_F32, 0, SPA_CPU_FLAG_SSE, 4, mix_f32_sse },
+	{ SPA_AUDIO_FORMAT_F32P, 0, SPA_CPU_FLAG_SSE, 4, mix_f32_sse },
 #endif
 	{ SPA_AUDIO_FORMAT_F32, 0, 0, 4, mix_f32_c },
 	{ SPA_AUDIO_FORMAT_F32P, 0, 0, 4, mix_f32_c },
 
 	/* f64 */
 #if defined (HAVE_SSE2)
-	{ SPA_AUDIO_FORMAT_F64, 1, SPA_CPU_FLAG_SSE2, 8, mix_f64_sse2 },
-	{ SPA_AUDIO_FORMAT_F64P, 1, SPA_CPU_FLAG_SSE2, 8, mix_f64_sse2 },
+	{ SPA_AUDIO_FORMAT_F64, 0, SPA_CPU_FLAG_SSE2, 8, mix_f64_sse2 },
+	{ SPA_AUDIO_FORMAT_F64P, 0, SPA_CPU_FLAG_SSE2, 8, mix_f64_sse2 },
 #endif
 	{ SPA_AUDIO_FORMAT_F64, 0, 0, 8, mix_f64_c },
 	{ SPA_AUDIO_FORMAT_F64P, 0, 0, 8, mix_f64_c },