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Hello all:

All this talk about science and tuba got me thinking and brought me out of my lurking. We have all seen Rick Denny's 186/York master comparison... It is interesting, but I've always wondered if player input, bias, volume, or mic placement might have skewed the results. I am certain that Mr. Denny attempted to minimize this... but human error is always a concern. Additionally, it is a small sample size.

I am interested in taking an acoustic snapshot of a LARGE variety of horns, with no player input. I don't know how familiar many of you are with sound engineering, but often, when setting up a PA, the engineer will generate a sweep tone, and record it - to EQ out oddities in a room. I happen to have an IK - Loud MTM speaker set at home that calibrates this exact same way to aid in audio mixing a few projects. These near field monitors have internal circuitry to automatically correct for accoustic oddities across the aural band. So... what would happen if you were to take a similar technology: a well calibrated speaker at a fixed length from a tuba bell, and record the sweep tone at the reciever? Would the accoustic profile (captured for each valve combination) provide an diagnostic comparison between models of tuba/specimins? Would it help explain why a certain valve combination is a challenge to play at certain registers? Would it show a leak somewhere in the horn over its age? A fingerprint if you will as it ages? Would you be able to learn that certain tubas "types" respond to your accoustic input better than others?

This is a curiosity at the moment. Musings of a mad man. Thoughts appreciated!

I am no acoustic engineer, but I am an engineer.
FIRST OBSERVATION
In engineering we "calibrate" instruments. We calibrate them, say, every year.
This involves testing an attribute of that instrument against a known (validated) standard.
In calibration "human error" is also taken into account, if it plays a part in the outcome of that calibration.
It could mean 2 different people taking the same measurement, later comparing any discrepancy between the two readings.
SECOND OBSERVATION
In engineering we study "variation" and, for highly regulated industries, we try our best to manage it and reduce its impact on quality.
In what can be described as "artisan" tuba manufacture there will be lots of variation, some subtle & others not.
That is why one tuba next to another tuba, of same the model, may sound very different, even if blown by the same player, same room, same everything....
In the hands of a great "artisan" maker, you get the greatest of musical instruments, eg. Stradivarius.
The more that production quantities increase, the greater the difficulty in maintaining quality of a great instrument. More "artisans" are needed and some may not be as good as the Master maker.
I am guessing Yamaha are less "artisan" than many other instrument makers(?).
THIRD OBSERVATION
Years ago when I visited Boosey & Hawkes in Edgeware (London) they had some acoustic contraption fitted to the receiver of a trumpet.
Not sure exactly what it was doing, but it made a humming noise which changed frequency from time to time during the test.
FINALLY
I think the engineering and science of brass instruments (and their manufacture) is absolutely fascinating.
If I were young, again, I could easily scope a doctorate or two around a few topics that would be enlightening.
May be if I win the lottery.........

Geoff

The following link covers the subject in detail.

Highly recommended reading.

http://newt.phys.unsw.edu.au/jw/brassacoustics.html

Bob Tucci
Munich

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