Flat due to oval tubing?

[P@rick]

Hi all,
My Besson 993 is overall flat. I’m about to cut the main tuning slide, but I noticed that the tubing right after the main tuning slide is oval shaped. That part of the tubing has an S-curve and exactly around that area its oval shaped. It could be a production error or it could be induced by excessive force while it was used, but it should not be oval. I checked other Besson 993 Tubas and they are not oval in that area.
Could oval tubing be the cause of the tuba being flat?
Thanks!

[Dan Schultz]

I doubt it unless it's REALLY flattened. It's not unusual for a tube to be flattened a slight bit in bent areas. Crooks are seldom perfectly round. But... you'll never know for sure unless you fix it.

[P@rick]

I doubt it unless it's REALLY flattened. It's not unusual for a tube to be flattened a slight bit in bent areas. Crooks are seldom perfectly round. But... you'll never know for sure unless you fix it.

It's not REALLY flattened, but the other two Bessons which I compared were perfectly round
Thanks!

[imperialbari]

So now it is a matter of cleaning the interior and then having the right balls?

[tusabtuba]

No, cut the slide. Tusabtuba

[P@rick]

Conn 20J tubas have oval tubing in their pistons...yet there seems to be a consensus that a "tuning bit" inserted between the receiver and the mouthpiece is recommended.

bloke "if-then"

...so...oval tubing makes a Tuba sharp...so...you are saying I need to make more tubing oval to make my Tuba less flat?

[Dan Schultz]

Conn 20J tubas have oval tubing in their pistons...yet there seems to be a consensus that a "tuning bit" inserted between the receiver and the mouthpiece is recommended.

bloke "if-then"

...so...oval tubing makes a Tuba sharp...so...you are saying I need to make more tubing oval to make my Tuba less flat?

. The tuning bit is more to overcome ergonomic issues.

[imperialbari]

Wasn’t a tuning bit calculated into the design of the 2XJ series? Purpose being flexible ergonomics.