diff --git a/Quake/snd_mem.c b/Quake/snd_mem.c
index fc4b9ba4..380be115 100644
--- a/Quake/snd_mem.c
+++ b/Quake/snd_mem.c
@@ -114,14 +114,12 @@ static void ResampleSfx (sfx_t *sfx, int inrate, int inwidth, byte *data)
 			}
 
 			// box filter
-			// FIXME: doesn't handle the start or end of the sound properly
 			
 			// box_half_width is the number of samples on each side of a given sample
 			// that are averaged together. 
-			// for the most common case, 11025Hz => 44100Hz, i.e. stepscale = 0.25,
-			// I determined that a box width of 5 (i.e. a box_half_width of 2) produces
-			// the best sounding results.
-			const int box_half_width = CLAMP(0, (1 / (stepscale * 2)), 8);
+			// for 44100Hz output, a box width of 5 (i.e. a box_half_width of 2) seems
+			// to sound the best
+			const int box_half_width = CLAMP(0, sc->speed / 22050, 4);
 			
 			if (box_half_width > 0)
 			{
@@ -129,26 +127,31 @@ static void ResampleSfx (sfx_t *sfx, int inrate, int inwidth, byte *data)
 				int history[box_half_width];
 				memset(history, 0, sizeof(history));
 				int box_sum = 0;
-				for (i = 0; i < outcount; i++)
+				for (i = 0; i < (outcount + box_half_width); i++)
 				{	
-					const int sample_at_i = getsample(sc->data, sc->width, i);
-					
+					// calculate the new sample we will write
+					const int sample_at_i = getsample(sc->data, sc->width, CLAMP(0, i, outcount - 1));					
 					box_sum += sample_at_i;
 					box_sum -= history[0];
-					
 					const int newsample = box_sum / box_width;
 					
-					const int write_loc = CLAMP(0, i - box_half_width, outcount - 1);
-					
-					// before writing the sample at write_loc, copy it to the end of the history buffer
+					// shift the entries in the history buffer left, discarding the entry
+					// at history[0] and leaving a space at history[box_half_width-1]
 					int j;
 					for (j=0; j<(box_half_width-1); j++)
 					{
 						history[j] = history[j+1];
 					}
-					history[box_half_width-1] = getsample(sc->data, sc->width, write_loc);
 					
-					putsample(sc->data, sc->width, write_loc, newsample);
+					// save the sample we are going to overwrite at history[box_half_width-1]
+					const int write_loc = i - box_half_width;
+					history[box_half_width-1] = getsample(sc->data, sc->width, CLAMP(0, write_loc, outcount - 1));
+					
+					// only write the new sample if it lies within the bounds of the output array
+					if (write_loc >= 0 && write_loc < outcount)
+					{
+						putsample(sc->data, sc->width, write_loc, newsample);
+					}
 				}
 			}
 		}