Fix for intonation on old Conn BBb?

[Sam Gnagey]

A friend of mine has a lovely old large Conn BBb from around 1918. He loves the sound of the horn, but the F partials are unworkably flat. Has anyone come up with a fix for this problem? He's thinking of having it cut to CC. I did a converson of one of these a long time ago and didn't solve this problem in the process. That just moved it up to G. It'd also be great to hear from some of you with old Conns that have or don't have this seemingly endemic tendency.

[iiipopes]

Bloke has a theory (if I'm stating it correctly) that the large girth of the bottom bow contributes to the flat 3rd partials, as on Holton 345's & Conn 2XJ's.

[EdFirth]

In A Treatice on the Tuba there's a picture on pg.118 of Mr Stauffer holding a huge old Conn front banger with a curtain rod fashioned into a master tuner. Maybe that's an option? Ed

[UDELBR]

Bloke has a theory (if I'm stating it correctly) that the large girth of the bottom bow contributes to the flat 3rd partials, as on Holton 345's & Conn 2XJ's.

I thought he said it was the top bow that was the culprit. Maybe he'll chime in.

[Gilligan]

I ran into a problem very similiar on an old Ambassador cornet. I found that the valves were aligned poorly so they didn't come up to the correct open position so all open notes were badly flat, almost a half step. I would check for something like that before I start trying to change circumfrences of pipes. Conn's manufacturing quality was better than to put out horns with such a problem.

You will need a small bore scope to be able to see into the valves through the slides.

Good Luck

[TheHatTuba]

,

[iiipopes]

Bloke has a theory (if I'm stating it correctly) that the large girth of the bottom bow contributes to the flat 3rd partials, as on Holton 345's & Conn 2XJ's.

I thought he said it was the top bow that was the culprit. Maybe he'll chime in.

yup. My guess is the top bow. It seems to me (just from very non-scientific visual/aural observations) the smaller diameter the top bow, the higher the 3rd partial.

Thanks for the correction. So -- do you take it off, slice a small strip out of the seam and put it back together to fix it?

[Michael Bush]

Here is a picture of the front of a Conn BBb from around that time that does not have this particular intonation problem. I am sure it has been modified in the past, because not all the tubes have the end rolled. Also, though it's not so clear in the picture, the straight pieces of the main tuning slide don't seem to be original. Maybe having a look at this one without the problem will help you fix the one you're looking at?

(The flat notes on this example are above the F that is always discussed. The B and C above it are flat, the C unworkably so, and I play it with 4. I've been contemplating having #1 cut to try to fix it.)

photo.JPG

[termite]

Slightly off-topic, but why is everyone so obsessed with playing C in the stave on first? (And other fifth partials). Just play it on fourth like the octave below. Sixth partials are much easier to control, especially if the note is the fifth of the scale. (Apologies for mini-rant).

Regards

Gerard

[Michael Bush]

Slightly off-topic, but why is everyone so obsessed with playing C in the stave on first? (And other fifth partials). Just play it on fourth like the octave below. Sixth partials are much easier to control, especially if the note is the fifth of the scale. (Apologies for mini-rant).

Regards

Gerard

I find using 4 awkward, but maybe that's just habit.

[termite]

With a three valve tuba you can try first and third although it will probably be very sharp. On many older British tubas (my Boosey&Hawkes Imperial), the fifth partials are high enough to be useable with a bit of lipping.

Regards

Gerard

[kingconn]

Hey Sam, I hope you were able to use some of that old info that came the Conn research labs.
If you play 3rd partial "F" and hold it , you can run your hand over the bugle, I think you'll find an antinode about where the bottom bow meets the 1st branch. Visually that area looks disproportionally big to me. I'd hold the horn so that that area is down and get somebody to pour in about a quart of water in and try that. I think the Eb jumbo bottom bow and part of the 1st branch might fix it.
mike

[termite]

I'm not sure if there is a fix for three valve tubas. Three valve British brass band instruments use the compensating system working off the third valve. In the case of Bbb tubas low C and B (first and third, first, second and third) feel like there is a rag stuck down the bell. (Low F and E below the stave don't seem too bad). Although as I said you can usually lip the fifth partials on these instruments.

Both of my BBb's have the first slide all the way in so a quick push for C in the stave is not an option.

I have long yearned to be able to do all my slide pulls with a second main slide instead of jumping between the first and fourth slides. Maybe two extra main slides - one with a trigger that returns to the same position for pushing and a more normal one for pulling.

It must be about time for someone to jump in and remind us all that real men wrestle notes into tune with their bare lips..........

[sloan]

Bloke may have "accidentally" found a fix for this on my 36J. If it works, I'll let him explain it.

It involves replacing the top bow with a part that doesn't quite fit...

[Sam Gnagey]

Hey Sam, I hope you were able to use some of that old info that came the Conn research labs.
If you play 3rd partial "F" and hold it , you can run your hand over the bugle, I think you'll find an antinode about where the bottom bow meets the 1st branch. Visually that area looks disproportionally big to me. I'd hold the horn so that that area is down and get somebody to pour in about a quart of water in and try that. I think the Eb jumbo bottom bow and part of the 1st branch might fix it.
mike

So, would replacing the 1st branch with a Conn (or other maker) monster Eb 1st branch fix the problem? Anybody tried that? We're willing to cut it to CC if that replacement branch will work. I'll have to get some measurements to see if it's even possible.

[kingconn]

I'd try the water trick 1st and see what happens. I played 3 valve upright a couple of years ago with a big dent on the small side of the bottom bow and thought the horn played great. Took magnets and took the dent out and played it later and noticed the 3rd partial was flat. I didn't have the heart to knock a dent back in and try again.
mike

[SousaSaver]

Now that you mention it, I recall in high school that the band director dented some of the new euphoniums for the purpose of improving the intonation.

Oh boy...

(no offense to you Ian)

[termite]

I've heard a few stories of dents improving intonation, normally it happens by chance.....

[cjk]

If this is one of those 6/4-sized Conn BBb tubas (which I'm assuming it is), then I would expect that parts from a monster EEb will certainly not fit.

This is a really interesting idea, cheap too:

Hey Sam, I hope you were able to use some of that old info that came the Conn research labs.
If you play 3rd partial "F" and hold it , you can run your hand over the bugle, I think you'll find an antinode about where the bottom bow meets the 1st branch. Visually that area looks disproportionally big to me. I'd hold the horn so that that area is down and get somebody to pour in about a quart of water in and try that....

I figure that if a note is flat, then there's some spot in the bugle that's too big in diameter. The water may narrow that spot. If you put the tuba on top of a table and play it with a tuner, then rotate it a little to move the water, then play it with a tuner, then rotate it some more, you might find where the tubing is too big. If you find the spot, then you could try shaping some brass "patches" for the inside of the horn to make that spot a bit more narrow. I would expect this would take quite a bit of experimentation and lots of pulling the tuba apart, but could be very useful to you in the long run. Depending where the patches needed to go, the soldering could be extremely difficult if the spot is in the middle of a bow.

I think that if I were doing this, I'd have somebody helping me hold the tuba while doing the water experiment. I figure a 6/4 Conn tuba is already quite heavy and adding water will just make it heavier. It also might function as a rudimentary leak test. I really do think it would be worth a shot even if the test proves to be useless.

Something along the lines of Bloke's tuning valve might be useful, only tuned to a sharp half step. Play F 1+3, then tune the extra valve to play E, play Eb 2+sharp half step, D 1+sharp half step, Db, 1+2+sharp half step (or substitute 3rd for 1+2), then play C 1+3 or 4th depending on how many of those notes are super flat.

I hope this helps,

Christian

[tclements]

A bullet hole in the right place might help. No, NOT in the player, in the horn!