diff --git a/libs/ardour/ardour/mix.h b/libs/ardour/ardour/mix.h
index 4b84b9e7ce..c619a2389b 100644
--- a/libs/ardour/ardour/mix.h
+++ b/libs/ardour/ardour/mix.h
@@ -27,73 +27,73 @@
 
 extern "C" {
 /* SSE functions */
-	LIBARDOUR_API float x86_sse_compute_peak         (const float * buf, uint32_t nsamples, float current);
-	LIBARDOUR_API void  x86_sse_apply_gain_to_buffer (float * buf, uint32_t nframes, float gain);
-	LIBARDOUR_API void  x86_sse_mix_buffers_with_gain(float * dst, const float * src, uint32_t nframes, float gain);
-	LIBARDOUR_API void  x86_sse_mix_buffers_no_gain  (float * dst, const float * src, uint32_t nframes);
+	LIBARDOUR_API float x86_sse_compute_peak         (float const* buf, uint32_t nsamples, float current);
+	LIBARDOUR_API void  x86_sse_apply_gain_to_buffer (float* buf, uint32_t nframes, float gain);
+	LIBARDOUR_API void  x86_sse_mix_buffers_with_gain(float* dst, float const* src, uint32_t nframes, float gain);
+	LIBARDOUR_API void  x86_sse_mix_buffers_no_gain  (float* dst, float const* src, uint32_t nframes);
 }
 
+LIBARDOUR_API void x86_sse_find_peaks              (float const* buf, uint32_t nsamples, float* min, float* max);
+
 extern "C" {
 /* AVX functions */
-	LIBARDOUR_API float x86_sse_avx_compute_peak          (const float * buf, uint32_t nsamples, float current);
-	LIBARDOUR_API void  x86_sse_avx_apply_gain_to_buffer  (float * buf, uint32_t nframes, float gain);
-	LIBARDOUR_API void  x86_sse_avx_mix_buffers_with_gain (float * dst, const float * src, uint32_t nframes, float gain);
-	LIBARDOUR_API void  x86_sse_avx_mix_buffers_no_gain   (float * dst, const float * src, uint32_t nframes);
-	LIBARDOUR_API void  x86_sse_avx_copy_vector           (float * dst, const float * src, uint32_t nframes);
+	LIBARDOUR_API float x86_sse_avx_compute_peak          (float const* buf, uint32_t nsamples, float current);
+	LIBARDOUR_API void  x86_sse_avx_apply_gain_to_buffer  (float* buf, uint32_t nframes, float gain);
+	LIBARDOUR_API void  x86_sse_avx_mix_buffers_with_gain (float* dst, float const* src, uint32_t nframes, float gain);
+	LIBARDOUR_API void  x86_sse_avx_mix_buffers_no_gain   (float* dst, float const* src, uint32_t nframes);
+	LIBARDOUR_API void  x86_sse_avx_copy_vector           (float* dst, float const* src, uint32_t nframes);
 #ifndef PLATFORM_WINDOWS
-	LIBARDOUR_API void  x86_sse_avx_find_peaks            (const float * buf, uint32_t nsamples, float *min, float *max);
+	LIBARDOUR_API void  x86_sse_avx_find_peaks            (float const* buf, uint32_t nsamples, float* min, float* max);
 #endif
 }
+#ifdef PLATFORM_WINDOWS
+LIBARDOUR_API void x86_sse_avx_find_peaks               (float const* buf, uint32_t nsamples, float* min, float* max);
+#endif
 
 /* FMA functions */
 #ifdef FPU_AVX_FMA_SUPPORT
-LIBARDOUR_API void  x86_fma_mix_buffers_with_gain (float * dst, const float * src, uint32_t nframes, float gain);
-#endif
-
-LIBARDOUR_API void  x86_sse_find_peaks     (const float * buf, uint32_t nsamples, float *min, float *max);
-#ifdef PLATFORM_WINDOWS
-LIBARDOUR_API void  x86_sse_avx_find_peaks (const float * buf, uint32_t nsamples, float *min, float *max);
+LIBARDOUR_API void  x86_fma_mix_buffers_with_gain       (float* dst, float const* src, uint32_t nframes, float gain);
 #endif
 
 /* debug wrappers for SSE functions */
 
-LIBARDOUR_API float debug_compute_peak               (const ARDOUR::Sample * buf, ARDOUR::pframes_t nsamples, float current);
-LIBARDOUR_API void  debug_apply_gain_to_buffer       (ARDOUR::Sample * buf, ARDOUR::pframes_t nframes, float gain);
-LIBARDOUR_API void  debug_mix_buffers_with_gain      (ARDOUR::Sample * dst, const ARDOUR::Sample * src, ARDOUR::pframes_t nframes, float gain);
-LIBARDOUR_API void  debug_mix_buffers_no_gain        (ARDOUR::Sample * dst, const ARDOUR::Sample * src, ARDOUR::pframes_t nframes);
-LIBARDOUR_API void  debug_copy_vector                (ARDOUR::Sample * dst, const ARDOUR::Sample * src, ARDOUR::pframes_t nframes);
+LIBARDOUR_API float debug_compute_peak               (ARDOUR::Sample const* buf, ARDOUR::pframes_t nsamples, float current);
+LIBARDOUR_API void  debug_apply_gain_to_buffer       (ARDOUR::Sample* buf, ARDOUR::pframes_t nframes, float gain);
+LIBARDOUR_API void  debug_mix_buffers_with_gain      (ARDOUR::Sample* dst, ARDOUR::Sample const* src, ARDOUR::pframes_t nframes, float gain);
+LIBARDOUR_API void  debug_mix_buffers_no_gain        (ARDOUR::Sample* dst, ARDOUR::Sample const* src, ARDOUR::pframes_t nframes);
+LIBARDOUR_API void  debug_copy_vector                (ARDOUR::Sample* dst, ARDOUR::Sample const* src, ARDOUR::pframes_t nframes);
 
 #endif
 
 #if defined (__APPLE__)
 
-LIBARDOUR_API float veclib_compute_peak              (const ARDOUR::Sample * buf, ARDOUR::pframes_t nsamples, float current);
-LIBARDOUR_API void  veclib_find_peaks                (const ARDOUR::Sample * buf, ARDOUR::pframes_t nsamples, float *min, float *max);
-LIBARDOUR_API void  veclib_apply_gain_to_buffer      (ARDOUR::Sample * buf, ARDOUR::pframes_t nframes, float gain);
-LIBARDOUR_API void  veclib_mix_buffers_with_gain     (ARDOUR::Sample * dst, const ARDOUR::Sample * src, ARDOUR::pframes_t nframes, float gain);
-LIBARDOUR_API void  veclib_mix_buffers_no_gain       (ARDOUR::Sample * dst, const ARDOUR::Sample * src, ARDOUR::pframes_t nframes);
+LIBARDOUR_API float veclib_compute_peak              (ARDOUR::Sample const* buf, ARDOUR::pframes_t nsamples, float current);
+LIBARDOUR_API void  veclib_apply_gain_to_buffer      (ARDOUR::Sample* buf, ARDOUR::pframes_t nframes, float gain);
+LIBARDOUR_API void  veclib_mix_buffers_with_gain     (ARDOUR::Sample* dst, ARDOUR::Sample const* src, ARDOUR::pframes_t nframes, float gain);
+LIBARDOUR_API void  veclib_mix_buffers_no_gain       (ARDOUR::Sample* dst, ARDOUR::Sample const* src, ARDOUR::pframes_t nframes);
+LIBARDOUR_API void  veclib_find_peaks                (ARDOUR::Sample const* buf, ARDOUR::pframes_t nsamples, float* min, float* max);
 
 #endif
 
 #if defined ARM_NEON_SUPPORT
 /* Optimized NEON functions */
 extern "C" {
-	LIBARDOUR_API float arm_neon_compute_peak          (const float * buf, uint32_t nsamples, float current);
-	LIBARDOUR_API void  arm_neon_apply_gain_to_buffer  (float * buf, uint32_t nframes, float gain);
-	LIBARDOUR_API void  arm_neon_copy_vector           (float * dst, const float * src, uint32_t nframes);
-	LIBARDOUR_API void  arm_neon_find_peaks            (const float *src, uint32_t nframes, float *minf, float *maxf);
-	LIBARDOUR_API void  arm_neon_mix_buffers_no_gain   (float * dst, const float * src, uint32_t nframes);
-	LIBARDOUR_API void  arm_neon_mix_buffers_with_gain (float * dst, const float * src, uint32_t nframes, float gain);
+	LIBARDOUR_API float arm_neon_compute_peak          (float const* buf, uint32_t nsamples, float current);
+	LIBARDOUR_API void  arm_neon_apply_gain_to_buffer  (float* buf, uint32_t nframes, float gain);
+	LIBARDOUR_API void  arm_neon_copy_vector           (float* dst, float const* src, uint32_t nframes);
+	LIBARDOUR_API void  arm_neon_find_peaks            (float const* src, uint32_t nframes, float* minf, float* maxf);
+	LIBARDOUR_API void  arm_neon_mix_buffers_no_gain   (float* dst, float const* src, uint32_t nframes);
+	LIBARDOUR_API void  arm_neon_mix_buffers_with_gain (float* dst, float const* src, uint32_t nframes, float gain);
 }
 #endif
 
 /* non-optimized functions */
 
-LIBARDOUR_API float default_compute_peak              (const ARDOUR::Sample * buf, ARDOUR::pframes_t nsamples, float current);
-LIBARDOUR_API void  default_find_peaks                (const ARDOUR::Sample * buf, ARDOUR::pframes_t nsamples, float *min, float *max);
-LIBARDOUR_API void  default_apply_gain_to_buffer      (ARDOUR::Sample * buf, ARDOUR::pframes_t nframes, float gain);
-LIBARDOUR_API void  default_mix_buffers_with_gain     (ARDOUR::Sample * dst, const ARDOUR::Sample * src, ARDOUR::pframes_t nframes, float gain);
-LIBARDOUR_API void  default_mix_buffers_no_gain       (ARDOUR::Sample * dst, const ARDOUR::Sample * src, ARDOUR::pframes_t nframes);
-LIBARDOUR_API void  default_copy_vector               (ARDOUR::Sample * dst, const ARDOUR::Sample * src, ARDOUR::pframes_t nframes);
+LIBARDOUR_API float default_compute_peak              (ARDOUR::Sample const* buf, ARDOUR::pframes_t nsamples, float current);
+LIBARDOUR_API void  default_find_peaks                (ARDOUR::Sample const* buf, ARDOUR::pframes_t nsamples, float* min, float* max);
+LIBARDOUR_API void  default_apply_gain_to_buffer      (ARDOUR::Sample* buf, ARDOUR::pframes_t nframes, float gain);
+LIBARDOUR_API void  default_mix_buffers_with_gain     (ARDOUR::Sample* dst, ARDOUR::Sample const* src, ARDOUR::pframes_t nframes, float gain);
+LIBARDOUR_API void  default_mix_buffers_no_gain       (ARDOUR::Sample* dst, ARDOUR::Sample const* src, ARDOUR::pframes_t nframes);
+LIBARDOUR_API void  default_copy_vector               (ARDOUR::Sample* dst, ARDOUR::Sample const* src, ARDOUR::pframes_t nframes);
 
 #endif /* __ardour_mix_h__ */