5 valve noncompensating vs. 4 valve compensating

[MikeMason]

I would think the real problem is in figuring out and engineering the extra lengths of tubing for the compensating portion of your plan.

[Wyvern]

No stuffiness on this baby

What is that Mike? I don't recognise.

That's what I've been doing to Besson Eb!! They are as open as a none comp with the ease of comp fingerings!!

Nice work Mike! I see the rotary 4th valve. So does the air still loop back through valves 1 to 3 to compensate the same?

[windshieldbug]

I'd go with 4 rotaries, and reachable usable main tuning slide, and good ears.

I think everybody here knows that I think Dr. Marzan had it right. Make it sound good, and learn to deal with the intonation, if you have to. Even comp horns need kickers...

[windshieldbug]

The valves would be hollow with brazed in tubes. Giving 100% volume throughout, and reducing weight

Very York-ish, actually. I've got a York 3-rotary valve althorn that has built-up rotors that are exactly as you described:

[iiipopes]

OK, here's a chart that compares the intonation from a purely mathematical point of view:

http://www.tuba.com/e/tuning_a_tuba.htm

With that chart, the 4-valve comp is marginally better in tune, and best of all is (no surprise) is a 3-valve comp.

But all is not a perfect world, as with the differences in bore, taper, etc., intonation is not mathematically perfect, although it's so damn close on my Besson it is scary.

With my frankenstein 186, for example, the midline D is flat as is characteristic. But second space C is right on first valve, and there are some other quirks at the extremes I don't worry about too much, as the slots are wide enough I just focus pitch and blow and don't worry about it. So, my vote in answer to the poll is, "Yes!" depending on the individual instrument.

Oh, and BTW, compensating rotors have already been done by Hirsbrunner. There is currently one for sale here:

http://www.gassermusic.ch/okkdetail.asp?OkkasionID=107