Low Bb is out of tune

[davewerden]

I guess I could file the leadpipe to make the mouthpiece go in further. That way the Bb could be in tune, but the other notes will probably be sharp.

Noooooo, I would not do that. It's tough to undo if it makes matters worse.

[Saxophilist]

Noooooo, I would not do that. It's tough to undo if it makes matters worse.

The instrument is kind of useless to me as it is without the Bb.

[davewerden]

The instrument is kind of useless to me as it is without the Bb.

Understandable! I'm fresh out of ideas.

[davewerden]

Understandable! I'm fresh out of ideas.

I take that back! Have you checked the valve alignment and checked for leaks?

[Saxophilist]

I take that back! Have you checked the valve alignment and checked for leaks?

How can I check that?

[notaverygoodname]

Now that is interesting. What does it mean to have a negative gap, is that the tip of the shank fitting in past the start of the leadpipe? I thought conceptually that the farthest you could push a mouthpiece in the receiver was up to the start of the leadpipe, unless perhaps the leadpipe is tapered down so that it is a smooth transition from receiver to leadpipe.

On my Adams, I can screw the receiver in or out so that the shank of my mouthpiece gets closer or farther away from the start of the leadpipe. I don't think I can go negative if I understand what you are saying.

Yes. Most instruments have a smooth transition from the receiver to the leadpipe. If you use a mouthpiece with a smaller shank than what the horn is designed for, you get a negative gap. For whatever reason, some horns will work with practically anything that you can shove into the leadpipe and it doesn't matter. Others...not so much. Pretty sure the Trombonium's reputation got ruined entirely due to its stupid proprietary receiver.

Of course, the OP already tested taping the shank and it didn't work, so I'm out of ideas.