Mismatched drum-head tensions deliberately destroy definite pitch in bass and snare drums

Evidence

Bass and snare drums are set up so as to be essentially non-pitched by setting a different tension on each of the drum heads, and therefore spreading the non-harmonic modes produced by the two heads widely in frequency. When they are struck the result is not pitch specific, and therefore they can be used to provide rhythm for music in any key. — David Howard, Jamie Angus, coustics and Psychoacoustics, 1318

Categorization

• XREF: Connects to how non-harmonic spectra underpinning percussive role in any key.
• corroborated: 2 independent passages support this claim — David Howard, Jamie Angus, coustics and Psychoacoustics, 1318