TubeNet

I thought it best to start a new thread for this question:

Can anyone who has (or has access to) a Mirafone CC (or BBb) tuba with the old style 5th valve tuning (short double whole step) measure the length of the 5th valve tubing circuit and post it here?

Thanks -

I have a BBb 1291 that I purchased the 2-3 combination fifth valve slide for. Is this what you are looking for?

And the slide is not a "short" double whole step. It would be right on to get the pitch. And compared to the 1st valve slide, it will be more than double the length of the 1st valve slide, or "long" because of each half step of the octave increasing logarithmically rather than linearly, and therefore requiring progressively more tubing to be in tune.

Dan,

I was thinking specifically of the long 5th valve on the rotary valve horns (186, etc.), but it certainly wouldn't hurt to get the measurement off of the tubing you mentioned.

iiipopes,

Thank you for correcting me - I mentioned it that because that's the way I've seen it called in previous conversations. So, if I were to add the length, of the 2nd & 3rd circuits in a Mirafone 186, it would be exactly the same length as the 5th valve in this case?

I've built slide extensions for every horn I've ever owned and could measure a slide to help you get in the ball park for your own slide.

I'll post a picture or two and some measurements probably tomorrow(busy day today).

If you are interested in exploring this tuning system and are ok with spreadsheets and math THIS: http://www.galvanizedjazz.com/tuba/5thvalve.html is a great resource.

I've since upgraded that spreadsheet to include a sixth valve and explored various tuning systems. Ultimately, for my own curiosity, I'd like to modify that spreadsheet to explore tuning on a double or triple tuba.. just to see if it's genuinely that much of a theoretical improvement.

From my explorations I've concluded that if you want to be as close to as in tune as possible on the most notes and only have five valves.. you really should use the 'double whole-step' fifth.

There are theoretical benefits to a six valve tuba for intonation(more alternate fingerings) BUT it's really only one note(low Eb on a CC tuba) that is better relative to a five valve tuba with a miraphone fifth. Relative to a 'standard' fifth valve adding a sixth valve makes a MUCH larger difference. A properly tuned 6 valve tuba is tuned such that 5+6 equals the miraphone fifth.

Final note: one of the things that came out of exploring the spreadsheet was that I had been tuning my long fifth with the wrong strategy. I had tuned it such that 45= low E on a CC tuba(234 is generally an in tune fingering on most tubas). Tuning it such that 235= low F turns out to solve a few things without harming much of anything. Either way, it works out to be a smidge shorter than 2+3 tuned to be a perfectly in tune double whole-step.

More info than you requested. Hopefully it was helpful.

joh_tuba,

Thank you very much for offering me your information - I am looking forward to receiving it!

Yes, that tuning is what I'm exploring. I'm thinking that the extreme low notes on a BBb tuba (C & B natural, specifically) will respond better with fewer valves depressed, hence the desire to try it, as opposed to the "flat whole step" I have now.

Bob

roweenie wrote:Dan,

I was thinking specifically of the long 5th valve on the rotary valve horns (186, etc.), but it certainly wouldn't hurt to get the measurement off of the tubing you mentioned.

iiipopes,

Thank you for correcting me - I mentioned it that because that's the way I've seen it called in previous conversations. So, if I were to add the length, of the 2nd & 3rd circuits in a Mirafone 186, it would be exactly the same length as the 5th valve in this case?

It would be the length of the 2&3 valve circuits together with either or both the 2nd and 3rd pulled to get the pitch in tune.

Since 3 alone is not a preferred fingering for most horns, many manufacturers make the 3rd valve circuit long, or at least give a lot of pull to the slide, so it can be adjusted to get 2+3 in tune.

roweenie wrote:Dan, I was thinking specifically of the long 5th valve on the rotary valve horns (186, etc.), but it certainly wouldn't hurt to get the measurement off of the tubing you mentioned.....

Generally... when I add a fifth valve I will measure the length of the first valve circuit (usually around 27" on a BBb tuba) and make sure the new slide has enough 'pull' to make it flat.

For a 2-3 combination fifth valve... the tuning circuit might be around 52" long.

Tuning circuit lengths are not all exactly the same depending on many things like bore and taper. I like to put circuits together 'long'. I can always take things apart and start trimming once I've actually blown the horn.

I just finished up this fifth rotor on a BBb Marzan. It's a flat whole step. (and I agree with your thinking that this is actually about 2 1/2 steps but I don't make the rules!)

Dan,

Very nice looking job!

Bob

The slide extension to convert CC B&S PT rotary tubas from 'whole-step' to 'double whole-step' adds approximately 15 1/4" of length to that slide.

If you already have a functioning fifth valve on your BBb tuba I would build an extension that adds a little bit more than that.

Good luck!