up for debate

[bloke]

Whatever causes it, there's an odd ingredient in the sound (similar to when one makes sounds into a PVC pipe) when a fiberglass body and bell elbow are encasing the end of sound column.

[matt g]

Whatever causes it, there's an odd ingredient in the sound (similar to when one makes sounds into a PVC pipe) when a fiberglass body and bell elbow are encasing the end of sound column.

It could be that the “periscope” design of those two elbows sets up another mode that can be excited.

Even though the sound pressure is moving longitudinally through the horn, those two elbows, specifically because they can “see” each other could set up their own standing wave.

A few measurements and spectral analysis could verify this.

[pjv]

About light/heavy, it is obvious that we want the tuba as least as possible to vibrate because that is a power loss. So thicker brass wil help but also the rigidity off the instrument has to be considerd.

So, you are saying research says thicker brass in horns is better than thinner? You DON'T want the horn to vibrate? Can you please explain? Interesting, I always assumed the opposite of each was better.

I´m not saying which is better because that is more a human feeling.
Since the air colum is what makes the sound anything of the tuba vibrating steals energy of the air colum.
The addition of the tuba vibrations can make the tuba sound better or worse and have other effects.

Here you can see that trumpet bell vibrations changes the instruments impedance.
https://www.comsol.se/paper/download/83 ... _paper.pdf

Here a short abstract, to bad not a free paper.

https://www.researchgate.net/publicatio ... s_A_review

I'm wondering if this might (at least partially) explain why I've had bad experiences with red brass tubas. Maybe too much of my energy gets lost in the tuba itself.

[bloke]

Probably, most people haven’t spent much time messing around with 4 inch and 6 inch plastic pipe…but I have, since I own some rural land.

When talking or yelling at the person who’s helping you (with some or most of the sound from your voice going into the pipe), you hear a funny “plastic noise“ inside a plastic pipe. It doesn’t happen with other types of pipe.

[jtm]

Of course, we're all familiar with brass sousaphone bell "after-ring".

What's up with that?

I played a brass sousaphone in college marching band and confess I was not familiar with bell "after-ring". Maybe just not attentive enough, or maybe never practicing alone. But when I tried one recently I definitely heard it and was even wondering if I need to get something fixed?

[bloke]

after-ring...

Some do, and many don't.

Those that do (often, oddly, some of the thick/heavy ones) are really annoying (to me).

[peterbas]

...

[KingTuba1241X]

I remember the old 70's King 2350's we had in high school marching band (23 players strong) used to all vibrate with after ring, and I personally kind of like the sound from behind the bell.