Dented Tone

[Mr Mark]

Hello again!

Returning tubist here...after leaving this instrument out of my repertoire for a very long time I am playing again (25+ years). My embouchre definitely needs work. However I have been hard at it for about six weeks now and am making some gains. I have also thought to buy a bunch of Kelly mouthpieces to see what works better before buying real deals as any one mouthpiece could be more than I paid for the tuba itself ($175 ).

As an aside, some notes I really have trouble with...I think the uppers may be embouchre related more than anything (E3 & Eb3 in particular - is this common for newbies?). However some of the lower notes specifically related to the third valve are lacking. I realize this might just be embouchre/more air, but can the dents in the third valve tubing be having a seriously negative effect on things here? If so I may see about repairing them seeing as how the tuba was so cheap first off - if not maybe they can be lived with?

I should state for the record it is a Huttl 800 (West Germany).

Thanks for looking!

[groth]

I'd say yes, it looks dented almost 1/2 way down the diameter of the tube which will affect air flow and cause tone to change.

[toobagrowl]

Agree with groth. That 3rd valve knuckle looks badly dented in to the point it effects playability. Guessing your low notes utilizing the 3rd valve are quite stuffy in sound and response? You should be able to take it to a decent brass tech to fix. They will probably have to unsolder the nickle-silver slide portion off the knuckle, and use dent rods/tools to rub out the dents, then re-solder the slide section back on

[tbonesullivan]

Those are definitely going to affect response. There is a significant lose of air flow and space, in a critical turn. I would take it to a tech and have them iron it out as best they can. I'm not sure if they would be able to detach the knuckle from the valve, but they can definitely get at it from the other direction.

[peterbas]

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[Donn]

Right, a dent would actually increase air flow, as measured at that point - the volume of air passing any point is constant, while the cross section is smaller, so the speed of air must increase. Possibly speed up (and slow down) to the point where it would make a difference, though I guess not likely.

Anyway ... the way I learned to use the 3rd valve, it's for only those notes that can't be played with the other two. So for example assuming a BBb tuba, I wonder if you have tried playing D with the third valve, which one wouldn't ordinarily, and comparing that with the correct 1 & 2.

Try it first on a higher note, perhaps the D above, to determine the real pitch for the 3rd valve, which should be lower than combined 1 & 2, and then shoot for that pitch the octave below, not in-tune D. (If it appears that the third valve plays an in-tune D ... I guess that could be your problem right there, so fix that and try everything again.) The point of this experiment is that if the 3rd valve is shot for lower notes in general, there should be an audible difference between a D played with it and without it. If the 3rd valve problem is specific to certain notes because the dent reflects sound waves or something at an awkward place in their wave formation, then it may be a waste of time if D is not one of those notes.

[MaryAnn]

Lots of us use the third valve pulled to be in tune for those notes that would be sharp with 1+2. On anything that isn't compensating.

Dents will make the thing really hard to play if the dents are messing up the nodes. Rick Denney might know enough to make a wild guess about that, but if someone else has the same trouble with the same notes, you can make a reasonable assumption that it is a problem with the instrument.

[Donn]

Lots of us use the third valve pulled to be in tune for those notes that would be sharp with 1+2. On anything that isn't compensating.

Right, this is about compensating for the lack of compensation, if you like. If 1 is exactly a whole step, and 2 is exactly a half step, then 1+2 will be sharp for a minor third.

If that were the beginning and end of such problems, then it would make sense to tune 3 to exactly a minor third. But it isn't. 1 + 3. I need to go quite a ways beyond that, a half step beyond a fourth, with 3 valves. So - with a three valve tuba - I basically have to tune everything flat, particularly 3.

[UDELBR]

Many of y'all reference "air flow" regarding dents. It's a common mistake, thinking of a brass instrument in terms of wind resistance and turbulence. The entire purpose of the length of the instrument is to promote standing waves of acoustic energy which bounce back from the bell to the mouthpiece (and back and forth, continually reinforcing the note being produced). Dents deeper than about 1/3 the pipe's diameter have a significant negative effect on the promotion of standing waves, so those are certainly worth fixing.

While it's a helpful pedagogic tool to say "blow *through* the instrument", very little air actually does go through the instrument. It's merely fueling the buzz.

[tokuno]

There will be no loss of airflow because it is not needed to create a standing wave. The airflow is only needed to make our lips vibrate, if the air can escape some other way than through the tuba it plays just fine.

The Rijke tube demo didn't seem to resonate *heh* with any of my kids, but I remember it helping me to understand air's role in generating a standing wave via our lips, as opposed to the sound coming from whooshing volumes of air through the tubing.
https://youtu.be/onxZl9vb46o?t=22

[peterbas]

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[Mr Mark]

Wow lots of information here, thanks for the replies!

I will do my best to find a repair tech to remediate these dents. There is also some denting on the leadpipe (16mm diameter reduced to 13mm in spots), I'll get an in person tech opinion first to see how far I go here...I'm guessing this is giving me some issues and would prefer to straighten this section out.. I have also discovered a couple spots where the feet of bracing has become detached and will need those resoldered. I'm guessing these pipes are too small for a magnet dent repair (5/8") ?

On another note three days of polishing this thing looks a million times better. Now to find a lacquer friend!

To indicate how newbie I am, I was unaware of the 3 valve vs the 1+2. From everything I can tell, the 1+2 are where they should be and the 3 produces a note about 20 cents flat of the 1+2. So it doesn't seem to bad. However every note that uses the third valve is indeed stuffy and lacking response...if the piece isn't any kind of forte then forget it .

I will have to get to that light reading PDF sometime soon if I want to get through it this lifetime . Kidding aside I do appreciate the information!

Thanks for your responses!!!