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Hi all - A number of recent posts on here and on some of the Facebook tuba/euph/low brass pages, have raised a question for me.

There are times when we are asked to play at louder dynamic levels, match the volume of an ensemble, and/or fill a particular space with “sufficient” sound, and so we (low brass types) talk about it in terms like playing louder/fuller/with more resonance/making more sound (not to mention some less savory euphemisms). Especially in modern American tuba playing, it seems like a decent amount of value is commonly placed on a tuba player’s capability to make as much sound as needed (whether reasonable or not).

I’m not looking to debate how loud we should be playing (I think I have seen some threads on this, so it’s being addressed elsewhere). I’m interested in better understanding the design mechanics of volume. I feel like I have more of a grip on the human contribution to sound production (maybe because I’ve focused on it more.) - the size, quality, and efficiency of breath (in and out) directly impact the volume, velocity, and direction of the airstream that fuels the sound. There are also legitimate anatomical limitations to human capacity (individually or in general).

I’d be happy to hear your thoughts on that, but what I’m really wondering is to what degree - if at all - different elements of our equipment play relatively greater or lesser factors. So, what are the basic impacts of the size/design of the horn (overall or part of it, like the bell diameter, lead pipe, where and how quickly internal dimensions/diameters increase) and/or of the mouthpiece (similarly, overall size and shape, as well as aspects like throat and backbone)?

I’m sure I missed at least some important aspect and I know that anything relating to increased sound might have other trade-offs (like clarity, etc.), but that’s why I’m asking. As I’ve been thinking about it recently, I just feel like I don’t have a great understanding of how mouthpiece/instrument design affect this aspect of playing.

If there is already a thread on this or if there are other (relatively accessible) resources that you can recommend, I’d appreciate those too. Thanks in advance for your thoughts and direction.

Don

Yes, it would be good to know more of the physics behind brass tone production.

I've read a couple places that the low frequency component of the sound stays the same for a given pitch/player/horn/mp no matter how loud you play it. Maybe you can sort of throttle it at the lowest human dynamic, but that's about it. When you increase intensity, what you actually do is broaden the frequency range of the output by lighting up higher overtones (and more non-pitched noise). You can't actually turn the fundamental up or down, although you can do things that your brain mistakes for turning the fundamental note up or down.

On bigger tubas this base/bass volume is higher, and it might be VERY roughly linear to the size of the tuba.

Decades ago when Conn was a leader in the field, they did a lot of research into the acoustics of brass instruments, and some of this work has turned up. In my files I have one of the papers that concerns dynamics, and mouthpieces. The results were obtained by examining the overtones present when brass instruments are played. They concluded that at low dynamic levels the tone had fewer overtones, and the overtones were reduced in strength relative to the fundamental pitch. As the dynamic level increased the number of overtones in the tone increased, and significantly the strength of the overtones increased faster than the fundamental did. At a certain point, when playing very loud, the lower overtones didn't get any louder but the higher overtones would increase dramatically. These observations of course compare well with practical experience, as you get louder the sound gets brighter, and at some very loud point, there's a change in feel, where the sound gets edgy and it's very hard to play much louder.
As to mouthpieces they found that a small shallow mouthpiece reduced the fundamental in the sound- please note that it did not say it increased the high overtones, they only sounded louder because there is less fundamental. A large deep mouthpiece reduced the high overtones, please note that a deep mouthpiece did not increase the fundamental, it only sounds that way because the overtones are reduced in volume. So while you can change the tone with a mouthpiece of different volume, you are doing so by moving further away from the instruments efficient sound production. This is a good argument for picking an instrument that puts out the tone you need as a matter of design, and finding a mouthpiece that is a good match for the instrument. It further suggests that trying to make a horn sound different from what it is with big mouthpiece changes will always be a compromise.

What I have found to be helpful with achieving a wide dynamic range is a relatively large volume interior somewhat open throat and backbore, but.most importantly a very efficient wind apparatus. I try to avoid any and all isometrics between the diaphragm and the lower abdomenal muscles
As well as any tension aroumd the throat. I can feel that my wind supply moves directly and without interference right to the chops
With this set up it takes very little effort to open the embouchure a bt and just feed the wind by simply pulling in on the abs. Imho if their is. A bt too much or not enough rresistance at the mouthpiece the may be some bacup or if too large just a sucking awayof the breath
So a few things do need to be coordinated

Just trying clarify what modelerdc mentioned, let me know if I'm getting this right...




At low dynamic levels:
The overall sound has fewer overtones
The overtones are reduced in strength relative to the fundamental pitch

As the dynamic level increases:
The overtones increase significantly faster than the fundamental does
At some point, the fundamental stays the same, but higher overtones still increase

Example: as you get louder the sound gets brighter, but eventually, there's a change in feel, where the sound gets edgy and it's very hard to play much louder; it’s more noticeable in a small bore horn than a larger bore horn of the same key (same length).

Small shallow mouthpieces:
Reduce the fundamental
Overtones only sound louder because there is less fundamental
Seem to have more ‘brilliance’ in the upper range

Large deep mouthpieces:
Reduce higher overtones
The fundamental only sounds louder because there are fewer overtones
Seems to have more ‘core’ on the fundamental / lower register / 2nd partial ???


An instrument’s characteristic (best) tone is found when a particular mouthpiece has the cup volume, cup shape, and throat size that best resonates (enhances) the instrument itself. When any of these things are changed to enhance a certain characteristic (response, low register, intonation, etc), the instrument and mouthpiece combination together becomes overall less efficient at everything.

So, find out what mouthpiece works best with your horn and (if needed), have the rim altered to suit your embouchure.

I've always been interested in exactly how a manufacturer decides what mouthpiece to use with their horns, and I wonder whether other manufacturers were as meticulous as Conn in this regard.

I have an original York Al-Tru mouthpiece that (I assume) came with the model 91 6/4 BB flat (it was in the case with the horn when I bought it) and although I'm no expert on mouthpieces, appears to be quite shallow, and more "cup-shaped", compared to a Helleberg.

On my 345, I find that the Geib style mouthpiece (cup-shaped also?) works better (for me) than deep funnel-shaped ones.

Is this contrary to (current) popular wisdom?

bloke wrote:I'm not certain that "fundamental" (all by itself - were it able to be isolated sonically) sounds the way many people believe that it sounds.

That's very interesting. Since any given note automatically comes with its overtones, and thereby gives us the sound we're accustomed to, would we even recognize it as a note, without them?

Although I'm hardly a scientist, it seems to me, given the characteristics of sound, fairly impossible to ever know this (but it would be really cool if it could be done).

At times here we've been asked to believe that the fundamental is inaudible, or nearly inaudible, and we unconsciously infer its presence from the rest of the partial series.

The agreement in pitch with the other players is going to make a world of difference. I have heard smaller, better groups "out blow" bigger, not better groups, in a most decided fashion. The reinforcement (or not) of the pitches among the players figures to get the credit (or blame).

As an individual, you can strive to be the one agreeing with your neighbor.

bloke wrote:You can download sine waves here, and listen to them...whatever frequency you want, and for longer or shorter lengths of time...

...not a particularly interesting sound.

http://www.audiocheck.net/audiofrequenc ... netone.php

Wow - I listened to the examples in the above link, and even though the sound is theoretically pure, it's difficult (for me) to listen and not hear overtones, albeit somewhat faint.

Maybe it's simply due to conditioning (or "imagining").

(Or maybe, I'm just crazy).

Wait, I just remembered I do play the tuba.....

bloke wrote:

roweenie wrote:

bloke wrote:You can download sine waves here, and listen to them...whatever frequency you want, and for longer or shorter lengths of time...

...not a particularly interesting sound.

http://www.audiocheck.net/audiofrequenc ... netone.php

Wow - I listened to the examples in the above link, and even though the sound is theoretically pure, it's difficult (for me) to listen and not hear overtones, albeit somewhat faint.

Maybe it's simply due to conditioning (or maybe even "imagining").

Speakers create them.

Ah. Does that mean I'm not crazy, then?

Indeed