TubeNet

rbbivens wrote:I listened to a performer (Washboard Hank - an excellent entertainer, BTW) play a silly, hand-made "tuba" constructed from 2" drain pipe. He used a standard tuba mouthpiece, but the "bell" was literally a kitchen sink!

I think the OP was saying that the diameter of the pipe (bore) was 2". Not the length. But my small amount of knowledge of acoustics tells me that tuben's answer is still right.....just in a different direction. The buzz wasn't LOW enough to get to the fundamental of that size pipe and since it was so high, it's no different that a trumpet player putting their mouthpiece in a tuba and screeching out high notes....nothing slots, but it can sound cool when done well.

: - )

tuben wrote:

rbbivens wrote:Can anyone explain why the notes don't slot?

It is because the fundamental vibrating pitch for a 2" length of pipe is much higher than your buzz.

Too much sink. Give time and red rot will take care of the problem.

GPT wrote:By this definition, all brass instruments, even the trombone, are technically cylindrical; some are just more cylindrical than others.

Cornets, flügelhorns, french horns, euphoniums, and tubas are cylindrical? News to me, and I don't think so. Interesting that you said "even the trombone," as if it's the least believable as a cylindrical-bore instrument...that one really is cylindrical.

All brass instruments are part cylindrical-bore and part conical-bore. It's a question of percentage that puts them in the two classifications.

How to skip the design phase of brass instruments entirely:

http://www.youtube.com/watch?v=2eS4pDY210s

Klaus

GPT wrote:

Todd S. Malicoate wrote:Cornets, flügelhorns, french horns, euphoniums, and tubas are cylindrical? News to me, and I don't think so. Interesting that you said "even the trombone," as if it's the least believable as a cylindrical-bore instrument...that one really is cylindrical.

All brass instruments are part cylindrical-bore and part conical-bore. It's a question of percentage that puts them in the two classifications.

Whoops... I said the wrong word there. I meant that all brass instruments are technically conical resonators, when you're speaking in physics terms, and I completely screwed up. Oh, well...

It's more complicated than that.

First - brass instruments are a MIXTURE of cylindrical and conical sections.

Secord - (arguably more important) they have a bell section AND A MOUTHPIECE - both of which have profound effects on where the "slots" are.

The marvel is that this has all been balanced out by clever trial-and-error, and engineering, so that the slots you find on a typical brass instrument are reasonably close to what you might expect by applying the naïve "Conical Resonator" model.

so - if you are happy with the "conical resonator" model, and it gives you the right answers - keep on using it. Just keep in the back of your mind a little sticky note saying "lies, lies...all lies".

Nick Drozdoff, physics teacher as well as MF alum and 1st call session player, on his website has some great links to some videos he has made to demonstrate the effects of cylindrical v conical, and how as the horn becomes more cone like the overtones become closer and closer together.

I was doing ok until she got to the muted section. I just threw in the towel as well then. I give up too.

sloan wrote: so - if you are happy with the "conical resonator" model, and it gives you the right answers - keep on using it. Just keep in the back of your mind a little sticky note saying "lies, lies...all lies".

Oh, yes! In fact, the clarinet cited as our cylindrical bore instrument, actually isn't rigorously cylindrical. And then there's the flute ... I think the terms aren't to be taken literally or as a physical explanation, the point is really just that the clarinet's a little odd acoustically. I'm pretty sure the drain pipe isn't going to partake of this peculiarity.

Donn wrote:I think the terms aren't to be taken literally or as a physical explanation, the point is really just that the clarinet's a little odd acoustically. I'm pretty sure the drain pipe isn't going to partake of this peculiarity.

Well, yes, it will tend to take on a similar characteristic, as both are so cylindrical, the primary overtone resonance is not an octave, but an octave and a fifth. That's why the clarinet in its chalmeau register sounds "hollow," the cylindrical aspect suppresses the octave overtone.

iiipopes wrote:

Donn wrote:I think the terms aren't to be taken literally or as a physical explanation, the point is really just that the clarinet's a little odd acoustically. I'm pretty sure the drain pipe isn't going to partake of this peculiarity.

Well, yes, it will tend to take on a similar characteristic, as both are so cylindrical, the primary overtone resonance is not an octave, but an octave and a fifth. That's why the clarinet in its chalmeau register sounds "hollow," the cylindrical aspect suppresses the octave overtone.

You're over-simplifying the acoustical principles. Try it. Play on a reasonably long pipe, a hose-o-phone or for that matter a trombone without the bell section. I'm finding that I can play (on the valve section of a valve trombone), partials 1, 2, 3, 4, 5. The clarinet would not have been able to produce all those notes, only the odd ones.

That's because it's "cylindrical", but just as a much more cylindrical flute doesn't demonstrate this quality at all, neither does a brass instrument with a cylindrical shape.

The notes you get out of your hose-o-phone would be surprisingly low, if it were in the stopped pipe family along with the clarinet. That's how a 5 foot long bass clarinet can play Db below the bass clef, along with the baritone saxophone that's a foot or two longer. But the hose-o-phone doesn't work like that, nor will a drain pipe or anything played in manner of a brass instrument.

Yes, I oversimplified. Your longer explanation is more correct. But the point was that just because an instrument has a particular profile, without other criteria, does not inherently indicate how it will resonate, as you aptly pointed out.

With a flute, even though it is cylindrical, the embouchure is open, meaning you blow across it rather than into it. This also promotes the entire overtone structure. The clarinet, being both rather cylindrical and having what is considered a "closed" embouchure, meaning the reed can function like a cap on an organ pipe, also tends to truncate the even overtones.

As an acoustic physicist can explain better, with a closed-end resonator like a brass or reed instrument, when the body is made more conical, why the overtones start behaving differently than with a pure cylinder, and start coming together, eventually reaching the spacing we have come to expect on a good brass instrument.

For example, taking a reed organ pipe: an organ builder can take the exact same boot, reed and shallot, and 1) attach a cylindrical resonator and make a more clarinet-sounding pipe, or 2) attach a more conical resonator and make a more trumpet sounding pipe. The same holds true for brass instruments, where the lips and embouchure perform the same function as the reed tongue in the organ pipe, or a reed woodwind instrument, where the mouthpiece reed performs the same function.