bass tuba low range question and theory

[J.Harris]

I was wondering if anyone here has a theory as to why there are low range issues with Eflat and F tubas. Specifically the dreaded low C ( or corresponding low Bflat for the Eefers). I would like to suggest that when a horn is shortened from 18' to 13' (BBflat to F) but the bore is not similarly reduced, response problems occur. For instance, if the bore of the BBb was .800 than a corresponding bore for an F tuba would be approx. .576 (13'/18'=.722 or 72 percent. .800 x .72= .576). Am I totally off in left field here? Discuss... I'm interested to hear what others think about this subject. Thanks.

[joh_tuba]

It's not the bore size on its own that causes the phenomena.

I would argue that the bore has nothing to do with it but instead the problem lays in the rapid taper of the branches leading to the bell.

If you set most Ebs next to a B&S style F the actual body is MUCH smaller.. notably the bottom bow.

Willsons Fs and Ebs are smaller bodied horns and don't have problematic low registers. Small bodied Fs(Miraphone Firebird, MW182, Yamaha 621) don't have a problem low C even when they have a much larger bore than a B&S style F.

Bessons have a smaller bore AND compensating loop that build in some stuffiness which helps low range response.. they also have a relatively small bottom bow that feeds into a disproportionately large bell.

6/4 CCs often have problematic low register response regardless of bore size and small CCs almost universally have epic low registers.

It's my personal belief that a smaller bottom bow and bell on a PT15 could fix a few things without hurting much.

[Donn]

Based on a very small sample of tubas, I'd say with a disproportionately large bore you're less likely to have the feeble low C. My tubas do fit joh_tuba's analysis, in that an extravagantly large taper promotes feeble low C (bigger is not necessarily better), and I suppose a bunch of extra small tubing behind the flare just makes it worse.

(Skill!? what's that?)

[Ferguson]

I don't think bore is the only issue. Many tuba parts are about the same size or length no matter in what key the tuba is pitched. Bell, bottom bow, tuning slide, valve block, leadpipe - these are all the same length within a few inches on most tubas. These parts work fine on an 18 foot BBb tuba, but when you try to use the same length parts, even properly tapered, on a 12 foot F tuba (you say 13', I usually say 12', it's somewhere around there), the errors in proper taper throughout the shorter bugle are more significant, and the problems get worse IMHO.

Rotary F tubas can be especially problematic because the valve block is long and it's cheaper to use 5 or 6 rotary valves of the same bore rather than to machine each valve to a larger bore than the previous one. A few tubas have this tapered setup, but they are the exception rather than the rule.

What I have noticed is that many rotary F tubas compensate for the lack of expansion in the valve block by allowing the bore to jump right after the last rotor, where the tubing enters the tuning slide sleeve. I think that's where the low C problem is formed. I've been experimenting with fixing this now and again by putting a brass or plastic sleeve inside the tuning slide sleeves where this bore jump occurs. I was trying to mimic the effect of a tapered inner tuning slide tube. I've had some success with Alex, Cerveny, and B&S tubas. You can see the thread and photos here:

viewtopic.php?f=2&t=41660&p=361480#p361480

BTW, Getzen bass trombones have tapered tuning slide sleeves to mimic a conical bell section, the holy grail for some vintage aficionado bass 'bonists. (See: Elkhart Conn 62H.)

Not all F tubas have a poor low C. Many piston F tubas are great: Gronitz 125, Miraphone 1281, MW2250, Yamaha 822 come to mind. Some rotary tubas are excellent too, notably the Miraphone 181, 281, 381 (I can't think of any others that excel, maybe Willson?) I think the problematic horns tend to be B&S/MW/Cerveny rotary models. When you recycle parts among many different models, that's what you're going to get: suck. Also, isn't just about every B&S tuba .750" bore plus or minus? Yes, when you go cheap on the design, problems arise.

Note that some very good soloists choose Eb tubas. These days there are many excellent Eb tuba options, and one player thought it was just enough longer than an F tuba (14 feet vs. 12 feet) to avoid some of the errors in taper. YMMV...

Best,
Ferguson

[joh_tuba]

Not to put too fine a point on it.. but I'm actually inclined to believe that the bore size on it's own has very little to do with the 'dreaded low C' and it's mostly the stuff at either end of the bugle(leadpipe taper and too fast body taper) that are the primary culprit.

The bore size can affect low register response only in so much that a certain amount of stuffiness helps guide folks that haven't worked on their 'skill and drill' to the correct buzz. Conversely, a larger bore more open instrument often has an effortless singing high register. Most lead trumpets are excessively large bore for example.

A smaller leadpipe has the benefit of adding stuffiness and improving low register response but in a much more consistent(even from note to note) manner.

****More importantly, the larger the body the more inefficiently the standing wave is able to bounce from the bell end back to the mouthpiece(supporting and reinforcing the buzzing lips). Sound waves do not travel in a straight line.. they move side to side while moving forward(technically that's probably not accurate either but go with me). The larger the tuba the more energy is lost bouncing back and forth. When a tuba is particularly inefficient on a given pitch it becomes critical that the buzz be exactly right in order to maintain the standing wave inside the tuba... hence the importance of 'skill and drill'.

Put more concisely, some bugles just flat out support a standing wave more readily. The Thor is one of those horns. Many smaller bodied horns do this as well while generally speaking larger bodied horns don't. Looking at design changes in the various MW 6/4 tubas.. the valve bore was the ONE thing that wasn't altered.. and yet the response curve has been all over the map.

Open to having my mind changed but this is what my experience and observations bear out.

[MikeMason]

I'm voting voodoo/trial and error.i don't think anyone knows what dimensions will equal a great tuba.we try new deigns in hopes of the perfect fix and just see what happens.trial and error-mostly error

[MikeMason]

Oops

[Art Hovey]

My limited experience suggests that a fat tuba with a long leadpipe generally has a bad low register. A tuba with a mostly conical bore, not too fat, and a short leadpipe generally has a nicer low register.

The former shape strongly resembles an "exponential horn", which for mathematical reasons has a "cutoff frequency". Such a horn is incapable of transmitting sound below that cutoff frequency. But I must confess that I have not actually calculated the cutoff frequency for anything resembling a tuba. Maybe someone else here has?

If not I'll get around to it one of these day.

[Jess Haney]

It's not the bore size on its own that causes the phenomena.

I would argue that the bore has nothing to do with it but instead the problem lays in the rapid taper of the branches leading to the bell.

If you set most Ebs next to a B&S style F the actual body is MUCH smaller.. notably the bottom bow.

Willsons Fs and Ebs are smaller bodied horns and don't have problematic low registers. Small bodied Fs(Miraphone Firebird, MW182, Yamaha 621) don't have a problem low C even when they have a much larger bore than a B&S style F.

Bessons have a smaller bore AND compensating loop that build in some stuffiness which helps low range response.. they also have a relatively small bottom bow that feeds into a disproportionately large bell.

6/4 CCs often have problematic low register response regardless of bore size and small CCs almost universally have epic low registers.

It's my personal belief that a smaller bottom bow and bell on a PT15 could fix a few things without hurting much.

Just to paraphrase, my Willson 3400 has a fantastic low register and fluid upper register. I don't know what exactly Willson did right but every Willson 3400 I have played has been fantastic. My 3100 is even fantastic and has a ROCK solid low F and Eb down to the pedal BBBb. Granted it does take a fair amount of practice, it speaks bigger and more solid than my Besson 994, and blows away the Miraphone 1291s I have played. My 2 cents

[modelerdc]

The only E flats I've played that had the low register problems described above were European Rotaries. My 4 valve compensating Boosey has even consistent response as you play chromatically down, all the way to the pedals. The compensating system helps with pitch, but I really doubt it helps with response. The yamaha non compensating E flat has a close copy of this bugle, and has a good response down low without the compensating system.
Unlike trumpets, which haven't changed much since the old French besson (basically a cornet made in trumpet shape, and copied by Bach as the basis for Bach trumpets) tubas are still evolving toward an optimal, and therefore stable configuration. As tubas come on the market that are better able to combine great sound with good intonation and response, older models that are deficient will slip from pro use to student or school use, and eventual scrapping. When I was in college in the '70s miraphone 186 and Alexander's were popular with pros and their students. But who goes to an audition with one of these today? The 186 has become the horn a student plays until they can get a modern usually piston valved horn with a bigger sound expected today. The few Alex's that are easy to play and tune are rare enough that they are a collectible vintage interest, a local high school here was given two older miraphone 180 model F tubas. The kids don't know how to play them so they sit in storage. I tried both, and both were very difficult to play around low C. You know the kind of low range that makes us give thanks for a good E flat tuba. The kind of F tuba that you use only when you have too, when the part is just too high, and requires no low range to speak of. The kind of F tuba the trombone section secretly wishes you didn't own. Beautiful high range, but who wants a tuba that doesn't have a low range as good as any compensating euphonium? By the time the school decides to sell them, the market will be flooded with better playing Chinese made clones of a better design. Currently a student line trumpet or trombone is essentially the same design as a pro model, but more cheaply made. The Chinese are going to bring this about for tubas. Already any one with $1600 to $2500 can a good playing new tuba. Used ones are beginning to appear under a grand, and as they become more common this price will drop. They are copying the better tubas out there, and this will drive tubas with inherent faults off the market. A generation or two from now all the tubas in production will have good sound, intonation, and response. Their will always be a niche market for pros who require the best possible quality. But second rate makers will have to undergo ongoing cycles to improve or go out of business.

[k001k47]

The only E flats I've played that had the low register problems described above were European Rotaries. My 4 valve compensating Boosey has even consistent response as you play chromatically down, all the way to the pedals. The compensating system helps with pitch, but I really doubt it helps with response. The yamaha non compensating E flat has a close copy of this bugle, and has a good response down low without the compensating system.
Unlike trumpets, which haven't changed much since the old French besson (basically a cornet made in trumpet shape, and copied by Bach as the basis for Bach trumpets) tubas are still evolving toward an optimal, and therefore stable configuration. As tubas come on the market that are better able to combine great sound with good intonation and response, older models that are deficient will slip from pro use to student or school use, and eventual scrapping. When I was in college in the '70s miraphone 186 and Alexander's were popular with pros and their students. But who goes to an audition with one of these today? The 186 has become the horn a student plays until they can get a modern usually piston valved horn with a bigger sound expected today. The few Alex's that are easy to play and tune are rare enough that they are a collectible vintage interest, a local high school here was given two older miraphone 180 model F tubas. The kids don't know how to play them so they sit in storage. I tried both, and both were very difficult to play around low C. You know the kind of low range that makes us give thanks for a good E flat tuba. The kind of F tuba that you use only when you have too, when the part is just too high, and requires no low range to speak of. The kind of F tuba the trombone section secretly wishes you didn't own. Beautiful high range, but who wants a tuba that doesn't have a low range as good as any compensating euphonium? By the time the school decides to sell them, the market will be flooded with better playing Chinese made clones of a better design. Currently a student line trumpet or trombone is essentially the same design as a pro model, but more cheaply made. The Chinese are going to bring this about for tubas. Already any one with $1600 to $2500 can a good playing new tuba. Used ones are beginning to appear under a grand, and as they become more common this price will drop. They are copying the better tubas out there, and this will drive tubas with inherent faults off the market. A generation or two from now all the tubas in production will have good sound, intonation, and response. Their will always be a niche market for pros who require the best possible quality. But second rate makers will have to undergo ongoing cycles to improve or go out of business.

[Lectron]

I believe part of the dreaded F, G, Bb, C is due to the privileged tones and their
presence of nodes/anti-nodes relative to the 'real note'

[J.Harris]

Thanks for all the input on this subject. Very interesting.

[iiipopes]

The Eb 183 I currently have is wonderful in the low register, completely open and consistent all the way from open second line Bb down to below true pedal Eb. All horns vary. One time I had the opportunity to play two otherwise identical Miraphone detachable recording bell tubas literally two serial numbers apart. Mine was great. The other was stuffy.

Another aspect not discussed is the bracing, bends, dents and where they occur with regard to nodes and antinodes of particular pitches. If an antinode anywhere in the horn is damped or impeded, the horn will sound stuffy. If it is mechanically advantaged, then the horn will speak well on that note. That's why the legend of "The Dent" in the proper place helps low C-4th on an F tuba.

This is also why bloke likes short lead pipes: less chance of a critical antinode being caught up in the valve block or bracing.

[joh_tuba]

The leadpipe theory is interesting.

typical leadpipe length data points and proportional tuba length:
Piston Trumpet ~9" = BBb tuba 36" -Note tuning slide before leadpipe equals MUCH longer actual length to valves.
Rotary Trumpet/Flugalhorn ~4" = BBb tuba 16"
Trombone ~6" = BBb tuba 12"

Lengths are my best guess.

None of that might be pertinent to the topic at hand... but I think it puts things in perspective.

[sailn2ba]

Does it make a difference to the discussion if one recognizes that a sound wave is not the visual wave one sees in a vibrating string or on the surface of water. It is a pressure wave, compression and rarefaction of the transmitting medium. (I think) Response will change with diameter, especially around corners, and it will be subject to fluid dynamics, boundary layer and eddy behavior.

[UDELBR]

The leadpipe theory is interesting.

I vaguely remember a Schilke acoustical study which concluded that success/failure of a trumpet design was indicated by where the valve section was situated in the windway. Can't seem to find a citation right now ...

[Lectron]

I've had dreaded low C ( or corresponding low Bflat for the Eefers) on tubas with both long and short leadpipes.
Might be a coincidence, but common factors has been rather high sensitivity and efficient horns.
Also just an observation...More german/rotary than piston more conical horns

[joh_tuba]

I've had dreaded low C ( or corresponding low Bflat for the Eefers) on tubas with both long and short leadpipes.
Might be a coincidence, but common factors has been rather high sensitivity and efficient horns.
Also just an observation...More german/rotary than piston more conical horns

That theory sounds good on paper BUT the miraphone firebird has a longer than normal pipe AND large bore and no low C problems. The Yamaha 621 has a short leadpipe and smaller bore and no low C problems.

The common denominator is the small body.

[eutubabone]

Okay,
This was an amazing situation. I have an old 45 S MW f tuba built in 1974. It had terrible low range, very stuffy Low C and Gb (5 valves down), etc. I remembered that Lee Stofer had changed some braces on an old horn and changed the way it played so I tried it on my F tuba- oh my goodness! The problems I had with the low register passage on the VW concerto in the first movement are much easier to play. Everything is much clearer and easier to play- good grief! This is what I did. I measured the distance between the 4th valve tubing and the outside tubing before it connects to the bottom bow, and I found that there is a "sweet spot" for a perfect placement for a brace. The temporary brace is made out of a 1/2" dia. wooden dowel rod and is pressed into place. I experimented with various placements along the outside tubing of the tuba and the tubing for the fourth valve and found the best location based on performance feedback( sound quality, ease of response)- it plays like a different tuba! If you have a newer f tuba you may not have to go thru this process, but it worked for me on my old 45 MW. Thanks Tubenet folks for enabling me to discover this.

Brent Vokes