3-Valve Compensating Modification Theory

[Finetales]

I've been pondering various alternative valve configurations for both Frankenhorn jobs I have planned (alto euphonium and G bari bugle-based cimbasso). It's a fun game of "are there better ways to configure the additional valves after the first 3 so that you get additional mileage and less slide pulling, while also only using configurations that are possible to extract from using donor valvesets from dirt cheap bell-front baritones and the like". I highly recommend it to anyone looking for something profoundly useless yet mentally stimulating to do.

Anyway, one of the simplest thoughts I had early on is that if you started with a standard 3-valve compensating piston set, you could add a 4th valve that lowers the pitch by a perfect 5th instead of the usual 4th, and have a fully chromatic instrument. The real question in my mind was: would the 4th valve notes be anywhere near in tune? I tested it today by trying it on my single valve Conn 72H bass trombone, whose F attachment can be pulled to essentially Eb (just a tiny bit off the bumpers). Test results: the 5 notes in the Eb valve (Eb2 to B1) are either exactly on an open slide position or very close, and easily lippable if you don't move the slide to the exact right place. This translates very well to a compensating 3-valve set, whose valve combinations will be generally close to as in tune as a correctly-placed trombone slide. Logically, then, putting a quint valve after the 3 compensating valves (in a larger bore, presumably) will result in a fully chromatic instrument with minimal lipping or slide pulling required.

There's lots of compensating 3-valve tubas and euphs out there for dirt cheap or already in peoples' possession. If you loved how one of those played but wanted to make it fully chromatic, I think this would be the way to do it.

[LargeTuba]

I've thought about this too. A compensating set would allow you to set up the fourth valve for the low notes and use the 3v set for all notes that a 4th valve aren't required for.

BUT, a 4 valve compensating set would fix all your issues and not require any more thought. Compensated Ebs and BBbs are very unpopular in the states. One can be had for $500-$1000 if one is patient.

[Finetales]

Of course, this isn't meant to replace a 4v compensating setup at all. Just a way to make the most of a 3v comp set you might be starting with.

[bloke]

The added loops on the first and second pistons of a three valve compensating system add tubing to the 1-3 and 1-2-3 combinations, but only enough so as to be better in tune with the open bugle length for which they are designed.
A five step fourth valve would certainly offer the next pitch down, but the combination 5-2 wouldn’t make for a very nice next half step, and I’m thinking that 5-1 would err just as much on the other side of the pitch. What am I missing?
Below those, I could guess that some mixing and matching might result in serendipity (or a couple of things sort of close to serendipity), but I would probably rather play-test then do the root calculations, because I’ve found that the proof is more in the playing than in the mathematics.
(I’ve spent a few minutes here and there wondering about a cheater extension for 3-valve compensating system, and really never came up with anything that seemed practical… but if someone else does or has, congratulations!)
—————
To a related topic, I think I might possibly be completely re-tubing an Elkhart 72H playing slide next Wednesday night.

[Finetales]

A five step fourth valve would certainly offer the next pitch down, but the combination 5-2 wouldn’t make for a very nice next half step, and I’m thinking that 5-1 would err just as much on the other side of the pitch. What am I missing?

5-2 would be a useless fingering. On my 72H with the valve pulled to Eb (equivalent to this hypothetical quint valve), Eb is in 1st, D is just barely above 3rd (easily lippable), Db is a low 4th, C is a bit above 6th, and B is at 7th. With the 3-valve compensating block (which I realize is not PERFECTLY in tune, but you wouldn't know it on my 3v compensating baritone horn), this matches up to 4 for Eb, 14 for D, 124 (or 34) for Db, 134 for C, and 1234 for B. You would only have to lip the D, Db, and C just a tiny bit (or have a trigger on the 1st valve slide, which would also be useful for the sharp 6th partial) to get them exactly right. 14 and 234 would be pointless fingerings, unless you wanted microtones.

All play-tested, not using math!

[the elephant]

… profoundly useless yet mentally stimulating to do…

This describes all the work I've done to my horns in a nutshell.

[iiipopes]

Even Blaikley in the late 19th century abandoned the plan to have a 4th valve on a 3-valve comp to bring 1+2+3 B nat and low E nat into tune due to logistical difficulties, the rarity of those notes in standard literature, and the ability to lip down because, frankly, the notes were so stuffy they tended to play "flat" anyway.

Year ago, I tried to devise a plan to have a 4th valve to get the near-pedal notes below low E nat that just aren't there on a 3-valve B&H/Besson comp. It was an exercise in futility, due to the nodes and antinodes being in the wrong places through the valve block that simply damped any resonance or ability to make the notes speak.

Go the other way: everyone knows about the "dent" that makes low C on an F tuba actually speak promptly and in tune, due to the alteration of the behavior of the horn with where the nodes and antinodes are on a typical F tuba. The same thing happened to me on my Besson BBb 3-valve comp: it had a dent in the primary knuckle between the 1st and 2nd valves. This altered the response so that 5th partials were not flat and 7th partials were almost playable with simple fingerings. I had an overachieving tech that tried to take the dent out, and the 5th partials went flat. I took a ball peen hammer and gradually re-introduced the dent to get it back into tune.

Play a 3-valve comp for what it is: a near-perfect instrument (near meaning you may have stuffiness on 1+3 C and low F, but a small price to pay to have everything else in almost perfect tune) for what it is, with a range that encompasses 99 44/100 % of both concert band and brass band traditional literature, and use a Wick 1 mouthpice with as much air support as you can give it to bring out all of its room-filling, band-supporting, broad-but-still-with-core superlative tone and intonation it has to offer.

[bloke]

I understand:
so skip the half step valve, and other ones are close enough to make do.

[Finetales]

I understand:
so skip the half step valve, and other ones are close enough to make do.

Exactly. The D and C are close enough that it may be that the only note you would really need the trigger for is Db (if at all). You just have a couple of useless fingerings to skip, but more of the ones you have left are in tune than what you have on a 4v non-compensating instrument (which also has a useless fingering in 14).

Realistically, I think the only time this would be useful is if someone had a 3v compensating instrument they REALLY wanted to add the missing notes to, or if you were gathering donor parts for a Frankenhorn and had a 3v compensating block lying around.

It might be interesting to collect all of the different ways you could make a parts horn fully chromatic and how much work each method would be based on the different valve sets you have at your disposal. 3-valve piston sets, 4-valve piston sets, 3v compensating sets, 2 piston valves (from a G bugle), a lone piston and rotor (again from a G bugle), 3-valve rotor sets, 4-valve rotor sets, a single trombone/bass trombone rotor or fancier valve, and any combination of the above.

[iiipopes]

It might be interesting to collect all of the different ways you could make a parts horn fully chromatic and how much work each method would be based on the different valve sets you have at your disposal. 3-valve piston sets, 4-valve piston sets, 3v compensating sets, 2 piston valves (from a G bugle), a lone piston and rotor (again from a G bugle), 3-valve rotor sets, 4-valve rotor sets, a single trombone/bass trombone rotor or fancier valve, and any combination of the above.

I can do that right here, having played in concert or at least experimented with almost all of these systems. Pitch names are based (pun intended) on a BBb instrument playing American conventional concert pitch bass clef notation.

1) 3-valve. Everything low is sharp. Tradition is to pull the 1st valve slide slightly so 1+2 is not sharp, but not enough to throw off the centering of 1st valve notes, and to pull the 3rd valve slide to get 2+3 slightly flat (raise the back of the tongue to accelerate the breath velocity to get these notes in tune) and so 1+3 is only slightly sharp and can be lippeddown; avoid 1+2+3 if possible. Very few 3-valve tubas have an accessible 1st valve slide unless they have been modified in order to "ride throttle" on the problem notes.
2) 4-valve non-comp: better for those few notes that need it. 4th can be set dead for low C and low F; or slightly flat so 2+4 is only slightly sharp and 1+4 is still lippable; get a horn that has left-hand access to the 1st valve slide to "ride throttle" on the problem notes.
3) 3v compensating: the system I prefer. Each valve slide can be set "dead" and let the comp loops do most of the work down low; low G and low D are fingered 3rd valve instead of 1+2 to be in better tune. 1+2+3 is still sharp, but lippable. Many times the comp loops interfere with the lower anti-nodes and you have difficulty, if they speak at all, getting the "privileged" tones between low Enat and pedal BBb. A few notes, such as 2nd ledger line low C, may be stuffy, but still articulate.
4) G-two piston: good for pentatonic scales only.
5) G-piston & rotor: also only good for pentatonic scales.
6) 3v rotor: same limitations as a 3v piston non-comp.
7) 4v rotor: same limitations as a 4v piston non-comp, including access to the 1st valve slide to "ride throttle."
8) Trombone w/ rotor (F attachment) everything except lowest Bnat achievable; don't forget to lenghten your slide positions when engaging the rotor. You lose near pedal Bnat because you don't have an effective 7th position with the rotor engaged.
9) One not mentioned: conventional 5v noncompensating system: same limitations as a 4-valve non-compensating system, with one improvement: the 5th valve is now conventionally a "long whole step," meaning 4+1 is in tune. 4+2 is still slightly sharp, and you can fiddle with the valve combinations to get the notes between low Eb and pedal BBb reasonably in tune with minimal slide pulling, with one exception: near pedal BBnat is still problematic. worse, the 5th valve is sometimes erroneously called a "compensating" valve. It is not, in the sense of a Blaikley system. But since it is an alternative to get 1+4 in tune, I can see why it is called that.
10) Another not mentioned: when Peter Hirsbrunner, Sr. ran the company, he developed a 3-valve rotor compensating system after analyzing the Blaikley 3-valve compensating system. Reports are good, but oh, are these instruments extremely expensive, costing two to three times as much as a conventional 4-rotor HB tuba, used!
11) A third not mentioned: double-rotor true bass trombones. These I have not played. There are so many variations on which pitch the 2nd rotor is made, and variations on dependent or independent rotors, that a player needs to take a lot of time with the instrument to analyze both what the horn does and how to set the slides for various repertoire.
12) Practical alternative when playing a sousaphone. I have a custom-rebuilt by Lee Stofer "real" Conn 36K. The upper valve loop of the 1st valve circuit is easily reachable and manipulatable so on my souzy it has been transformed into a moveable slide so, having set the 2+3 combination in tune, I can pull the 1st valve for combinations, and push 1st valve for the characteristically flat fifth partial second space C.

And there you go.

[LeMark]

I have two euphoniums currently. a 5 valve non compensating king I built myself, and a 3 valve compensating besson. I like them both for different reasons. If I had to change anything about the king, I would add an inch to the bell diameter

If I had to change anything to the besson or any 3v compensating horn, it would be to add a trigger that shortens the 3rd valve loop a bit. The main problem with that setup is the fingering 2-3 is a little LONGER than a normal euph. Besson made an adjustment sometime in the 60's to try to fix that problem, but what they wound up doing was shortening the 3rd valve loop, which completely took away the advantage of the compensating system. Wouldn't be difficult these days to include a trigger except 3 valve instruments are marketed as student horns

[marccromme]

Hmm. Option 9) 5 valve non compensating does not need to use the very sharp 4+2 tritonus, the 5th valve can be tuned to give a very reasonable, slightly flat 2+3+5 tritonus, and a pretty good, slightly sharp 4+5 quint. These two combinations are the main raison d'etre for the 5 th valve tuned as a long whole tone = a large second from the quart.

Another option for a near perfect 6 valve instrument:
Combine two standard 3 valve blocks, coming from two instruments, the larger one a quart lower than the shorter.

For example, add a BB tuba 3 valve block after the 3 valve block of an Eb tuba, and shorten the Bb 3rd circuit (now being the 6 th valve) sligtly to give a clean forth. Or did the same with an F and an C valve block.

Then you have the same near perfect normal chromatic tuning for all notes above the pedal tones as any 6 valve tuba, only difference is that the usual right hand pinky 4th quart valve is now the left hand ring finger 6th valve.

Quart is 6, Tritonus is then 5+6, quint is 4+6, small sext is 1+2+6, large sext is 4+5+6 or slightly flatter 1+4+6, etc

It has the added advantage that each hand uses the strongest 3 fingers only. ..

[bloke]

...so - when I buy expensive/shiny tubas and lease fancy cars to drive to rehearsals and gigs...that's not what y'all are referring to as "compensating", then...(??)

[arpthark]

10) Another not mentioned: when Peter Hirsbrunner, Sr. ran the company, he developed a 3-valve rotor compensating system after analyzing the Blaikley 3-valve compensating system. Reports are good, but oh, are these instruments extremely expensive, costing two to three times as much as a conventional 4-rotor HB tuba, used!

Baltimore Brass has one for $4,000:

https://www.baltimorebrasscompany.com/p ... -tuba.aspx

I played it a few months ago when I was there. Pretty nice horn.

[iiipopes]

10) Another not mentioned: when Peter Hirsbrunner, Sr. ran the company, he developed a 3-valve rotor compensating system after analyzing the Blaikley 3-valve compensating system. Reports are good, but oh, are these instruments extremely expensive, costing two to three times as much as a conventional 4-rotor HB tuba, used!

Baltimore Brass has one for $4,000:

https://www.baltimorebrasscompany.com/p ... -tuba.aspx

I played it a few months ago when I was there. Pretty nice horn.

Oh, shucks! I don't have the cash right now.

[LeMark]

There's some close up shots of it in this video near the 4 minute mark

[bloke]

I wonder if there's some ear plugs that can filter all of that out except human conversation? If not, maybe cut the volume of it in half, and raise all detected sounds an octave or something...

... I think it would be easier to take if that rumble were up in the baritone horn range, and - if people came up to speak to me - I could probably tolerate everyone's voice sounding like they were in elementary school.

[2nd tenor]

I’ve seen but neither held or heard a three valve compensating Eb that’s had a fourth valve added.
This guy in the UK does it, but it ain’t cheap. https://www.m-j-c.co.uk/page-8/

[LeMark]

I’ve seen but neither held or heard a three valve compensating Eb that’s had a fourth valve added.
This guy in the UK does it, but it ain’t cheap. https://www.m-j-c.co.uk/page-8/

that's a 4 valve compensating Tuba that has had the piston 4th valve replaced with a rotor 4th valve. I think that conversion makes a lot of since

[2nd tenor]

I’ve seen but neither held or heard a three valve compensating Eb that’s had a fourth valve added.
This guy in the UK does it, but it ain’t cheap. https://www.m-j-c.co.uk/page-8/

that's a 4 valve compensating Tuba that has had the piston 4th valve replaced with a rotor 4th valve. I think that conversion makes a lot of since

Yes, that’s what the picture shows. What I saw, in the ‘flesh’, was a three valve compensating Eb Tuba that had had a fourth valve (rotary type) added. As I recall the pipe between the valve set and tuning slide was severed and both sides bent inwards at 45 degrees to place the fourth valve below the standard three. The 45 degree angle of attack probably helps with airflow on rotary valves, I can’t quite recall the track of the fourth valve loop - I think it was one large circular loop - but did marvel at how right the whole thing looked.

In theory this mod shouldn’t intonate that well, but in practise I suspect that it’s worthwhile doing for Brass Band players / playing; the probably stuffy 1+3 combination is avoided and the 4+2 combination is probably near enough in tune for practical purposes and much less stuffy than the 1+2+3 combination.

A three valve compensating BBb: https://simonettitubacollection.com/ins ... piston-ca/