fix post-filter shift

Author: ArdenButterfield

README.md

@@ -312,7 +312,7 @@ function renderWavesImpl(settings, fft, p) { return (playback = false) => {
 
   // time shift the signal by half the filter order to compensate for the delay
   // introduced by the FIR filter
-  reconstructed.forEach( (x, n, arr) => arr[n - 100] = x );
+  reconstructed.forEach( (x, n, arr) => arr[n - Math.floor(settings.antiimaging)] = x );
 
   // render FFTs --------------------------------------------------------------
   // TODO: apply windows?