diff --git a/audio/sinc.c b/audio/sinc.c
index 545f53c5f0..1024fbd056 100644
--- a/audio/sinc.c
+++ b/audio/sinc.c
@@ -71,7 +71,7 @@
 #elif defined(SINC_HIGHEST_QUALITY)
 #define SINC_WINDOW_KAISER
 #define SINC_WINDOW_KAISER_BETA 14.5
-#define CUTOFF 0.95
+#define CUTOFF 0.962
 #define PHASE_BITS 10
 #define SUBPHASE_BITS 14
 #define SINC_COEFF_LERP 1
diff --git a/audio/test/sinc_test.m b/audio/test/sinc_test.m
index 57173ce833..1c7401fcb2 100644
--- a/audio/test/sinc_test.m
+++ b/audio/test/sinc_test.m
@@ -12,9 +12,10 @@ subplot(2, 1, 2), plot(rarch_kaiser - real_kaiser), title('Error');
 %%
 % 4-tap and 8-tap are Lanczos windowed, but include here for completeness.
 phases = 256;
-bw = 0.375;
-downsample = round(phases / bw);
-cutoffs = bw * [0.65 0.75 0.825 0.90 0.95];
+ratio = 2.0;
+bw = min(1.0, ratio);
+downsample = round(phases / ratio);
+cutoffs = bw * [0.65 0.75 0.825 0.90 0.962];
 betas = [2.0 3.0 5.5 10.5 14.5];
 
 sidelobes = round([2 4 8 32 128] / bw);
@@ -22,28 +23,29 @@ taps = sidelobes * 2;
 
 freqs = 0.05 : 0.02 : 0.99;
 
-filters = length(taps);
-for i = 1 : filters
+%filters = length(taps);
+%for i = 1 : filters
+for i = 5
     filter_length = taps(i) * phases;
     
     % Generate SINC.
-    sinc_indices = 2 * ((0 : (filter_length - 1)) / (filter_length - 1)) - 1;
+    sinc_indices = 2 * ((0 : (filter_length - 1)) / filter_length) - 1;
     s = cutoffs(i) * sinc(cutoffs(i) * sinc_indices * sidelobes(i));
     win = kaiser(filter_length, betas(i))';
     filter = s .* win;
 
-    impulse_response_half = 0.5 * upfirdn(1, filter, phases, downsample);
+    impulse_response_half = upfirdn(1, filter, phases, downsample) / bw;
     figure('name', sprintf('Response SINC: %d taps', taps(i)));
     freqz(impulse_response_half);
     ylim([-200 0]);
 
-    signal = zeros(1, 8001);
+    signal = zeros(1, 80001);
     for freq = freqs
-        signal = signal + sin(pi * freq * (0 : 8000));
+        signal = signal + sin(pi * freq * (0 : 80000));
     end
     
     resampled = upfirdn(signal, filter, phases, downsample);
     figure('name', sprintf('Kaiser SINC: %d taps, w = %.f', taps(i), freq));
-    freqz(resampled .* kaiser(length(resampled), 40.0)');
-    ylim([-80 70]);
+    freqz(resampled .* kaiser(length(resampled), 40.0)', 1, 16 * 1024);
+    ylim([-180 100]);
 end
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