A brass mouthpiece has a measurable popping frequency near 850 Hz.

Evidence

The addition of a mouthpiece at the other end of the main bore also affects the frequency of some of the modes. The mouthpiece consists of a cup-shaped cavity which communicates via a small aperture with a short conical pipe. The mouthpiece has a resonant frequency associated with it, which is generally in the region of 850 Hz for a trumpet, which is otherwise known as the “popping frequency” since it can be heard by slapping its lip contact end on the flattened palm of one hand (Benade, 1976). — David Howard, Jamie Angus, coustics and Psychoacoustics, 1273

The mouthpiece consists of a cup-shaped cavity that communicates via a small aperture with a short conical pipe. The mouthpiece has a resonant frequency associated with it, which is generally in the region of 850 Hz for a trumpet, which is otherwise known as the “popping frequency” since it can be heard by slapping its lip contact end on the flattened palm of one hand (Benade, 1976). The addition of a mouthpiece effectively extends the overall pipe length by an increasing amount. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1247

Categorization

• DEFINE: Defines ‘popping frequency’ as the trumpet mouthpiece’s own resonant frequency, hearable by slapping the rim.
• CANDY: Fun party fact: slap the open end of a trumpet mouthpiece on your palm and you hear its resonant frequency.
• corroborated: 2 independent passages support this claim — David Howard, Jamie Angus, coustics and Psychoacoustics, 1273; David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1247