diff --git a/libraries/audio/src/AudioHRTF.cpp b/libraries/audio/src/AudioHRTF.cpp
index 1d5b074db7..f2f0235ccb 100644
--- a/libraries/audio/src/AudioHRTF.cpp
+++ b/libraries/audio/src/AudioHRTF.cpp
@@ -673,8 +673,8 @@ static void crossfade_4x2(float* src, float* dst, const float* win, int numFrame
 // linear interpolation with gain
 static void interpolate(float* dst, const float* src0, const float* src1, float frac, float gain) {
 
-    float f0 = HRTF_GAIN * gain * (1.0f - frac);
-    float f1 = HRTF_GAIN * gain * frac;
+    float f0 = gain * (1.0f - frac);
+    float f1 = gain * frac;
 
     for (int k = 0; k < HRTF_TAPS; k++) {
         dst[k] = f0 * src0[k] + f1 * src1[k];
diff --git a/libraries/audio/src/avx512/AudioHRTF_avx512.cpp b/libraries/audio/src/avx512/AudioHRTF_avx512.cpp
index 682f5f2f77..a8bb62be35 100644
--- a/libraries/audio/src/avx512/AudioHRTF_avx512.cpp
+++ b/libraries/audio/src/avx512/AudioHRTF_avx512.cpp
@@ -9,7 +9,7 @@
 //  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
 //
 
-#if defined(__AVX512F__)
+#ifdef __AVX512F__
 
 #include <assert.h>
 #include <immintrin.h>
@@ -87,15 +87,4 @@ void FIR_1x4_AVX512(float* src, float* dst0, float* dst1, float* dst2, float* ds
     _mm256_zeroupper();
 }
 
-// FIXME: this fallback can be removed, once we require VS2017
-#elif defined(_M_IX86) || defined(_M_X64) || defined(__i386__) || defined(__x86_64__)
-
-#include "../AudioHRTF.h"
-
-void FIR_1x4_AVX2(float* src, float* dst0, float* dst1, float* dst2, float* dst3, float coef[4][HRTF_TAPS], int numFrames);
-
-void FIR_1x4_AVX512(float* src, float* dst0, float* dst1, float* dst2, float* dst3, float coef[4][HRTF_TAPS], int numFrames) {
-    FIR_1x4_AVX2(src, dst0, dst1, dst2, dst3, coef, numFrames);
-}
-
 #endif