Vintage Mouthpiece Alloys?

[Frank Ortega]

Question;

Has anyone done a study and comparison of the alloys in vintage mouthpieces?

I find that some of my favorite mouthpieces are from the 1920's and that they produce a warm and colorful sound.

Just curious.

Frank Ortega

[Doug Elliott]

Just had an array of New York and Mt Vernon Bachs, and Rudy Mucks, tested. They were rather unremarkable plain 360 brass just like we use now, with some random impurities but nothing out of the ordinary.

[Rick Denney]

Has anyone done a study and comparison of the alloys in vintage mouthpieces?

I find that some of my favorite mouthpieces are from the 1920's and that they produce a warm and colorful sound.

I would be willing to bet that the difference you note has to do with shape and not material. Think of it this way: Two different brass alloys will have nearly identical stiffness, the same density, and only slightly different strength. And given that a mouthpiece is never stressed to anywhere near its strength (except when it's dropped on the concrete), the difference in strength has no effect on the mouthpiece behavior. Thus, density (as it affects mass) and stiffness will define the behavior of mouthpiece material.

The question is, how much does stiffness and mass affect that behavior? I'm thinking: Not much.

All the various alloys of brass vary by only a few percentage points in density and stiffness. Even the bronze mouthpieces are only slightly denser, but their stiffness is about the same as brass.

But plastic mouthpieces are dramatically different. Brass is 45 times stiffer as a material than is Lexan, and over 7 times as dense. If a plastic mouthpiece has the same basic shape as a brass mouthpiece, it will weigh a seventh as much and have about 2% of its stiffness. Yet the plastic mouthpiece is not fundamentally different than a brass mouthpiece in the sound it produces. Slight different, perhaps--though even that can be argued. But not fundamentally different.

On a scale that could show the properties of both Lexan and brass, all the various brass alloys could be represented by a single dot. If the performance difference between Lexan and brass is subtle, the performance difference between different brasses is negligible.

And let's not forget that absolute mass and stiffness are controlled by the amount and placement of the material. The modulus applies to the material itself, but has to be multiplied by the cross-sectional area of the brass to determine stiffness across that plane. And mass is the product of density times volume. Mouthpiece outer shapes have varied from zero up to perhaps a factor of three to six (in the case of mouthpieces that look like the bottom half of a can of Red Bull). These differences dwarf the few percentage points of differences in brass alloy density and stiffness properties. People argue endlessly over those differences and whether they are real. If you really want to replicate an old mouthpiece, you have to replicate the outer shape as much as the inner shape. But I think even that doesn't have much effect.

Here are some numbers for different brass alloys (first number is percentage copper, second is percentage zinc):

(Density in pounds/cubic inch and modulus of elasticity in psi)

90-10 Commercial Bronze:
Density: .317
Modulus of elasticity: 16,700,000

85-15 "Red" Brass:
Density: .316
Modulus of elasticity: 16,700,000

80-20 "Low" brass:
Density: .313
Modulus of elasticity: 16,000,000

70-30 "Cartridge" Brass:
Density: .308
Modulus of elasticity: 16,000,000

65-35 "Yellow" Brass:
Density: .306
Modulus of elasticity: 15,200,000

60-40 Type 360 "Free-cutting" brass:
Density: .307
Modulus of elasticity: 14,100,000

Note that "yellow" and "red" mean different things in the materials world than they do in the tuba world.

Now, here's Lexan:
Density: .043
Modulus of elasticity: 339,000

And, because someone may be curious:

304L Stainless Steel (What G&W use, and I assume Dave Houser uses something similar):
Density: .289
Modulus of elasticity: 28,500,000

Typical titanium-aluminum-vanadium alloy (Ivan and Robert use an alloy with 6% aluminum and 4% vanadium):
Density: .160
Modulus of elasticity: 16,510,000

Rick "it's all about the shape" Denney

[bisontuba]

Hi-
One big difference I see is weight. I see many copies of original Hellebergs that don't even come close to the weight of the originals......
Mark

[Frank Ortega]

Very interesting response and data Rick! Thanks!

When I have had reproductions of vintage mps made, I have noticed differences in shape and thicknesses that I thought affected the sound. Of course, these perceptions are subjective and hard to pin down. But it's nice to keep those densities in mind.

Are there any mp makers who offer a selection of different alloys? Of course we know that several makers offer stainless steel, and titanium. Dillon used to offer Bronze as an option and Curry claims to have a special Alloy all their own. Any others I've missed?

Frank

[cjk]

Kelly makes plastic, stainless, and brass mouthpieces.

[Rick Denney]

Hi-
One big difference I see is weight. I see many copies of original Hellebergs that don't even come close to the weight of the originals......
Mark

If that is the case, then it's because they are machined to thinner sections. The Conn Helleberg with the modern curvy outer shape is pretty thin compared to many other shapes.

Rick "noting that titanium and plastic are lighter for the same shape, but stainless steel is heavier" Denney

[sloan]

Rick "it's all about the shape" Denney

And...it's not all *that* clear how much shape matters.

Shape of the rim is very important - to the individual player. Different styles and different requirements dictate subtle (and not so subtle) variations in the shape of the rim. It's not at all clear that an of that has any appreciable effect on the SOUND. [articulation...perhaps - although there I think you still need to know more about the PLAYER, and what he can and can't do].

Shape at the throat - probably has to be "smooth" (whatever that might mean). But, after you specify the diameter of the throat and take care to make the final approach "smooth" - what else is there, really?
It's realHard to separate out SHAPE from what I think is most important: VOLUME. [*effective* volume - after taking into account the amount of meat inserted into the bowl...]

From the throat on in, I don't see a lot of variation - things are pretty constrained by the receiver.
There has been some noise about shape issues at the very end of the shank, where the mpc meets the leadpipe - but I'm not sure that qualifies as "mouthpiece shape". It *should* be orthogonal to other issues.

So...bottom line:
a) match the rim size and shape to the player - I think this is a "comfort" adjustment, not "sound".
b) match the combination of throat diameter and cup volume to the pitch of the instrument
b1) these two parameters give you a nice two-parameter space to wander around in. In many ways, if you vary one, the change to the other is "forced".
b2) But, you also change more subtle characteristics of the sound and the playability - briefly, you can be "beginner friendly" or "expert friendly", and the two sides of that will never agree on what is "best".

In my opinion, once you specify:

a) rim width
b) throat diameter
c) cup depth (really "volume")

then you are down to making all the transitions "smooth". If there is magic there, I'm ignorant of it [hmmm - no surprise there!]. Of course, quality production leading to repeatability and fit&finish are *very* important - especially if you are going to stamp out 1,000,000 of them.

The real problem in forming opinions here is that the universe of mouthpieces is pretty sparsely sampled. You can't order up three mouthpieces that are "exactly the same except for ONE parameter". You have to make do with what's available. Usually, the designers will change *all* the parameters to what they think is the sweet spot. When you do an A-B test, you don't really get that much insight into WHICH parameter produced the change you think you hear.

One of my medium term goals is to produce a collection of "fast prototypes" that hold all of the parameters I have identified absolutely constant - while at the same time significantly varying "shape". I'm trying to find out "how wierd can I make the 'shape' without significantly affecting the sound?" I think we've lived through that experiment in OUTSIDE shape recently ("make it bigger! make it smaller! if it's different it might be better! oh...it's not..."). I don't think we've had the same attention paid to the INSIDE shape. At least, not in public.

[Doug Elliott]

Back to alloys...

I'm sure it's not common knowledge and they'd probably like to keep it that way but I'll spill it since I found out cutting one for threads...

Wick Heritage mouthpieces are not brass...

ANOTHER example of a company claiming the outside shape is the only difference, when it's not.

[ShoelessWes]

Back to alloys...

I'm sure it's not common knowledge and they'd probably like to keep it that way but I'll spill it since I found out cutting one for threads...

Wick Heritage mouthpieces are not brass...

Begs the question... what is it? They've always seemed rather soft to me.

[Doug Elliott]

No, they're not soft at all. Nickel silver.

[ShoelessWes]

No, they're not soft at all. Nickel silver.

Interesting! Density of .316 if them there internets are right. So similar to brass in that regards.

[Frank Ortega]

I don't think you can say that outer shape has no bearing at all on tone production.
For example, I detect a marked difference in playing the old style G&W (which I prefer) to the new style. I think, just like whether the leadpipe is on or off the bell, it depends on how much vibrancy is in the player's buzz and how sensitive the player is to it.

Very interesting fact about the Wick Heritage mps. Makes me want to go out and try one.

Frank

[Rick Denney]

Rick "it's all about the shape" Denney

And...it's not all *that* clear how much shape matters.

If we think of a mouthpiece as an impedance matching device with its own impedance response curve, then "smoothness" is a matter of impedance at important frequencies. That may not be smooth in the sense of how it feels to our fingers.

And that suggests to me that inside shape is important more than just its volume. Some shapes are likely to reflect certain frequencies back to the player, or allow certain combinations of frequencies to cancel each other, or damp out altogether. I would think the shape of the mouthpiece is as important as the shape of the bell of the tuba in shaping the timbre.

Remember that the literature talked about volume and throat size primarily with regard to intonation tendencies. I don't recall (though I'm sure you'll remind me) that translating to changes in the mix of overtones affecting timbre.

It will be very interesting to see if your experiments confirm that assumption on my part. But the question is: How will you avoid experimental bias? If the shape changes the feel differently than it changes the timbre, how will you control for the player's response to that feel? That "feel" bias undermines much in the way of personal mouthpiece testing, which is why people spend so long in their search.

Rick "waiting for data" Denney

[Ben]

No, they're not soft at all. Nickel silver.

I have an old Alex MP I like that is nickel silver. Honestly, I am certain I like the shape. Vlad at Dillion has copied two other Alexander nickel silver MP's for me, the copies (exterior and interior) played indistinguishably from the originals.

[Rick Denney]

No, they're not soft at all. Nickel silver.

Interesting! Density of .316 if them there internets are right. So similar to brass in that regards.

Nickel-silver is typically 65% copper, 25% zinc, and 10% nickel. So, it's mostly brass. But the nickel does add a bit of stiffness--just a bit. The density of that alloy is .314, and the modulus of elasticity is 17,400,000 psi. Alloys may replace more of the copper with nickel, up to, say, 18% or so of nickel. They have the same density but slightly more stiffness. Nickel-silver is not as machinable as free-cutting brass, according to the literature, but I'll bet Doug could talk about that more meaningfully than a materials data sheet could. More nickel in the alloy improves its machinabililty. It is definitely harder (stronger), even in its annealed state, but it is not much stiffer or denser. It might be easier to plate--Dan Oberloh would be the guy who could answer that.

In use, the material properties of nickel-silver are similar enough to brass that I can't imagine there being any discernible difference, even in feel, and certainly not in sound.

Rick "who gets material information from a reliable engineering source" Denney

[Ben]

Nickel-silver is not as machinable as free-cutting brass

FYI - I asked Vladimir if he would reproduce this MP's in nickel silver, and he politely laughed at me and told me nickel silver was to hard on his tools. I seem to remember reading somewhere about a certain manufacturer who had to bribe their workers fill orders for solid nickel silver tubas. Anecdotal at best, hear-say, but the preference from Vladimir I consider interesting.