2. Distance Music: Why Train Horns?
Why Train Horns??
Because they’re LOUD! Traditional instruments can’t produce enough volume (sound pressure level, or SPL, measured in dB decibels) to create Distance Music. To hear rhythmically significant differences in delays, hundreds and thousands of feet of distance between sources is required.
Electronic amplification could also make such long distances possible for traditional instruments. But four serious drawbacks make it impractical: 1. Electrical power of the magnitude necessary would be too heavy if stored in batteries or the lengths of the power distribution would be impractical over so many acres; 2. Electricity is dangerous, especially in the out of doors where it can rain – or in this case of this piece – around water; and 3. It might require a microphone – which, in the case of this kind of high amplification almost certainly guarantees screeching feedback. And, finally, 4, the dispersion and quality of sound would be limited to the audio chain and loudspeaker – changing the tonal color and loudness of the amplified instruments in unpredictable ways.
Train horns are the only acoustic instrument designed to be heard over large distances (3 miles), each able to produce about 140 dB. They have the advantage of being extremely rugged and dependable outdoor, all-weather devices, too. Best of all, they aren’t powered by electricity! They are powered by gas, usually compressed air. I chose to power them with one of the best, portable potential-energy storage devices available – steel cylinders of high pressure gas (in this case, Nitrogen, N2), each storing 304 cubic feet. That much gas powering each horn would provide several minutes of a single, high volume blast. But because I want each horn to only speak just long enough to get to pitch, each cylinder should last 15 to 20 minutes.
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