Very high pitches, higher than what humans can hear, are called ultrasound. A famous example is a dog whistle, and good quality headphones can reproduce sound considerably higher than 20 kHz.
At the other extreme is infrasound. Anything below 20 Hz is more likely felt, not heard. (That applies to the fundamental, not harmonics.) Few acoustic musical instruments can play pitches that low--the first is E flat octave 0, at 19.45 Hz. 32-foot organ stops can play in that range. The low C is 16.35 Hz in standard tuning.
The Sydney Town Hall Grand Organ has a 64-foot stop, so it can play pitches in the negative-first octave, the low C being 8.18 Hz. With audible overtones, pitches this low are heard as beats rather than tones, and have been described as sounding like timpani rolls.
Which led me to another experiment...
This might require some considerable skill by percussionists, and certainly a metronome. If a roll on timpani, or bass or snare drum, could be an exact number of strokes per second, it would simulate an extremely low pitch. A double-stroke roll at 16.35 Hz would be a similated C0, which would go well with a timpano tuned to concert C2 (65.41 Hz). The drum should be tuned an octave, two octaves or a perfect twelfth above the virtual pitch.
So far, I have timpani rolls with specified frequencies in two movements of my Second Symphony: XXXVI. Montana and XXXIX. Nebraska.
Also, if an organ is being used, one still can produce resultant tones, by playing parallel fifths to simulate lower registers. (In Symphony No. 1, ninth movement, I used a resultant B-2, or about 7.72 Hz.)
No comments:
Post a Comment