diff --git a/audio.md b/audio.md
index 4bf8e48..cedf2f9 100644
--- a/audio.md
+++ b/audio.md
@@ -160,7 +160,9 @@ The `W` bits correspond to waveform type:
 
 Upsampling will be performed by repeating sample values as many times
 as needed (2x, 4x, or 8x). The underlying sound engine is still
-expected to play sounds at 44.1 kHz.
+expected to play sounds at 44.1 kHz. For sounds which are not samples
+at a lower frequency using one of the lower frequencies will have the
+effect of "pitch shifting" the sample down one or more octaves.
 
 ## Appendix B: not currently supported