Soft to Loud

Soft to Loud - An Acoustical Comparison

I have received several requests to display some additional comparison trumpet spectra, so here is one such set. The trumpet is again my Mt. Vernon M/37 Strad, and the mouthpiece is my Stork 1.5C. I played a succession of center space Cs: p, mf, f,and ff. As I moved up from mf to f,and especially from f to ff,I had to back away from the microphone to avoid clipping on the recording, so the sound levels cannot be compared from spectra to spectra. The FFT analysis is taken from a sample block of duration of about 0.67s of the waveform after I had brought the signal back on scale.

Figure 1. Time series for the note envelopes used in this test.
The spectra were taken from areas where the was no clipping of the notes.
In the case of the ff (4th) example I had to take several steps back from the microphone.

As you can see, the spectra are markedly different at different dynamic levels. The person who made the request had predicted that as I began to blast the higher harmonics would be buried. That didn't quite happen, but the fundamental did grow dramatically until its amplitude was equal to the first few harmonics' amplitudes. Obviously, if you looked only at the first 5 or 6 overtones, you would guess that some were suppressed.

Figure 2. Bach trumpet, middle space C, Stork 1.5 C, p

Figure 3. Bach trumpet, middle space C, Stork 1.5 C, mf

Figure 4. Bach trumpet, middle space C, Stork 1.5 C, f

Figure 5. Bach trumpet, middle space C, Stork 1.5 C, ff

John T. Lynch