Why raw brass?

[windshieldbug]

Wouldn't having a hand on the surface of a tuba while playing have more of a dampening impact on the vibration of the horn than the finish?

Only if you have a hand that can cover all the surface area, like say, uh, LACQUER!

[Rick Denney]

Has anyone ever built a tuba out of solid lacquer to test the implied thesis that lacquer has a "dampening" effect?...

...or what if a solid lacquer tuba is less resonant that a solid brass tuba, but WHEN LACQUER IS APPLIED TO THE SURFACE of a brass tuba, it actually increases the resonance...??

bloke "Play for me, please - in less than ten seconds, in F# harmonic minor scale in three octaves -accending and descending - and in thirds...first unlacquered, then lacquered, then unlacquered again."

Lacquer only has a dampening effect when first applied.

Oh, you mean damping.

You make a good point. Scotch tape has a damping effect--I have the measurements to prove it.

But I don't know how elastic baked cellulose or epoxy lacquer is. I suspect it's pretty elastic, though not very flexible (epoxy is more flexible than the cellulose stuff). And it could be as elastic as the brass.

If so, then it should not have much damping effect as a result of hysteresis, which is what made the Scotch tape do its thing. The tape's adhesive probably contributed more damping than the tape itself, too.

Hysteresis is the absorption of energy during repeated strain cycles. Tires get hot because of hysteresis, etc.

If it doesn't contribute much damping because of hysteresis, then the only way it can change the resonance of the brass is by adding mass or stiffness. Thus, it should have the same effect as somewhat thicker brass. I'm quite sure the lacquer is considerably less dense than the brass, so a given thickness will add much less mass than the same thickness of brass.

Rock "who wonders at the weight of lacquer" Donnor

[Rick Denney]

Wouldn't having a hand on the surface of a tuba while playing have more of a dampening impact on the vibration of the horn than the finish?

Only if you sweat a lot.

Oh, you mean damping.

The tuba touches our body in several places, and not much provides more damping than a balloon full of jello.

I think but the brass can ring in the parts that are far from those contact points, because the ring attenuates out before it gets to those spots anyway. Some frequencies are affected more than others. I once noticed a surprisingly large resonance in a King 1241 at about 100 Hz. You could strike the upper bow of the tuba with the flat of the left hand and feel it vibrate for several seconds in the right hand and legs. The jello water balloon didn't damp that out that much.

Rick "who thinks the lacquer has no real effect" Denney

[Rick Denney]

[
Rick "who thinks the lacquer has no real effect" Denney

If a modification to read "no real effect of significance" is acceptable I wholeheartedly agree in the case of tubas.

For me, real = significant.

Rick "if you can't sense it, is it real?" Denney

[windshieldbug]

Posted by Rick Denney on August 19, 2001 at 00:21:28:

In Reply to: Re: Re: Re: Vibration, damping, and weight posted by Laurence on August 18, 2001 at 10:27:20:

I'm quite confident when I say that it won't affect the stiffness. But I'm not at all confident that it won't affect the sound.

For me, real = significant.

Rick "if you can't sense it, is it real?" Denney

No wonder we have traffic jams.

No wonder we have posting jams...

[SplatterTone]

If resonance didn't cause tremendous amplification of power, the tuba sound would be no louder than the buzz. We know that's not the case.

There is no amplification. The term is acoustic coupling. It relates to the efficiency of the transfer of energy. Amplification would violate laws of physics. It's the same principle that is behind horn loaded speakers. Take a small speaker and play some music through it with a one-watt amplifier, and you won't get much. Put that speaker at the small end of a concrete exponential horn that extends halfway down the block and opens up the size of your living room wall, and you will get ear-crushing volume. We should note that knocking on the concrete horn will get you that dull thud you mentioned later. And horns on horn loaded speakers tend to be rigid and produce a sound only slightly this side of a dull thud when knocked on.

If you excite the body of a tuba, it will resonate on a variety of frequencies, If it didn't, all you would hear is an immediately damped thud.

I'll emphasize your use of the word "variety", as in a whole lot. In fact it is broad spectrum, and varies throughout the tuba body. High Q and broad spectrum don't usually go together, which is the basis for my minimizing the role of resonance of the metal. I will certainly agree that as one travels through the tubing of the horn, the wall at any given point is more sympathetic to some list of frequencies. But this constantly varies throughout the horn, so I'll submit that it is a stretch to refer to the metal of the horn as a resonant body.

Of vastly more consequence is the resonance of the air column inside the horn. That is our resonant entity.

Even an unmusical clang that takes a while to attenuate indicates resonance. When you coat the material with a damping material, you lower the Q of the resonance of some of those frequencies and damp some of them out. The clang will be muffled, which means that its highest frequency resonances are the ones being damped out.

If the tuba were played by banging on it, you might have a point here. Any vibration in the tuba metal comes not from directly exciting the metal by banging on it, but by stealing energy from the air column. More vibration means more energy being taken. Less vibration mean less energy taken. Refer to my previous comment about the concrete exponential horn. If a concrete tuba could be built, it would respond to your knock with a dull thud. But (assuming the interior is smooth) I am quite sure that high frequencies would come sailing out of the bell in fine style; and low frequencies would be amazing.

Your point is what in the sound energy produces those frequencies?

That was not my point at all. My point was very simple -- we're talking physics 101, first semester. The brass gets it energy by removing energy from the vibrating air column. Which means less energy is left in the air column. Which means the vibrating brass can't selectively add to anything; it can only take away.

I think your points are entirely related to producing sound by banging on the brass. Although in moments of frustration, I might have been tempted to do this, thus far any sound produced this way on my tubas was accidental, and tonal quality of the sound produced in this manner was not my primary concern.

[Art Hovey]

Splattertone has got it completely right.

In an earlier post I remarked that it's the player who determines the sound of the instrument, not the finish. I did not mean to imply that a player can make a crappy small tuba sound like the CSO York. What I meant was that a good player can make two otherwise-identical tubas with different finishes sound alike. Or if he chooses to he can make them sound very different.

Differences attributable to the finish will always be insignificant compared to the changes in sound that can be created by the player.

And let's not forget the dampening effect of the plastic tubing that many of us affix to the rim of the bell. That has a much greater effect on the way my Yorkofone bell vibrates than any lacquer ever could. It also enables me to put the horn down on a rough surface without scratching anything.

[windshieldbug]

And let's not forget the dampening effect of the plastic tubing that many of us affix to the rim of the bell. That has a much greater effect on the way my Yorkofone bell vibrates than any lacquer ever could. It also enables me to put the horn down on a rough surface without scratching anything.

Whereas I put my so unadorned bell down almost everywhere, and enjoy the ringing sound that the reduced mass of the bell resounds with...

[Todd S. Malicoate]

a good player can make two otherwise-identical tubas with different finishes sound alike. Or if he chooses to he can make them sound very different.

And therein lies the problem with testing theories about lacquered/unlacquered tubas, at least until a robot tuba player, who plays in the exactly same way every time, is invented.

Todd S. "who thinks this topic really boils down to (in the minds of many Tubenetters)
...unlacquered = more resonant = better = winning a job = why bother practicing" Malicoate

[windshieldbug]

Why raw brass?

More nutrients than steamed brass.

[tubamirum]

When lacquer is stripped the player can tell something is different but not the audience. The effect is more noticable on large intstruments than small ( i.e. tubas vs tpts)

[SplatterTone]

... the player can tell something is different but not the audience. The effect is more noticable on large ...

Especially true of big, manly tuba players wearing women's underwear.

Don't you think my tone has a lovely silky quality tonight?

[Kenton]

Raw Brass because:

Repair persons like raw brass (or silverplate) for obvious reasons.

Players like it because because it gives them bragging rights.

I like it because I like the tactile feel of it.

So, do you suppose the makers made any compensation for lacquer when they converted from raw (or silverplate) to lacquer offerings?

[Wyvern]

Which smell is better, raw brass or silver plate?

Lacquer to my nose

[windshieldbug]

Which smell is better, raw brass or silver plate?

In CC or BBb?