Since perception of pitch by humans begins at ~20hz, hearing a sound at that frequency or higher creates the illusion of pitch where there isn't any. I did the math to find out how fast it needed to be and recreated a C major scale with a snare drum. The scale starts on C2 and ends on C3. For some reason, the pitch won't go any higher once you hit whole note=125, which is somewhere between C3 and C#3. Each note is shorter than the last because the speed is increasing and I was too lazy to do more math and find out how many 64th notes I needed to make them the same length. I might make this a series that experiments with sound and the quirks of Flat playback, starting with the Shepard tones I released the other day. If there is anything specific you would like to see, let me know in the comments and I'll try my best.