Trumpet Intonation Improvement with Multiple Helmholtz Resonator Terminations
W. T. Cardwell · The Journal of the Acoustical Society of America · 1969
The conventional trumpet mouthpiece has already been shown, theoretically and experimentally, to behave as a Helmholtz resonator termination of the trumpet air column, changing the apparent length of that column with frequency. Further theory indicates that for musically proper placement of the upper playing modes, a more nearly ideal termination would be a multiple Helmholtz resonator. Experiments confirm this.