When I was in college in the 1980's, all my tuba playing colleagues used rotary F tubas. Mostly they were B&S and Miraphone as I remember. What I do remember clearly is that the low range felt terrible on all these tubas. The worst note was the fourth valve low C, and there have been countless threads of discussion about this on Tubenet, as well as in numerous bars worldwide.
I understand why people put up with this: rotary tubas have a liveliness to their sound that is incomparable, it's the traditional German style tuba, for years it was all that was available, and historically F tubas were not the do-it-all instrument that many players expect today.
Rotary F players all say they just learn to deal with it. Fine. What surprises me is that with prices for many F tubas hovering around $10000 USD or more, players still put up with this odd feeling low range. And makers have done little about it. I played an Alexander F tuba at the Musikmesse this year, and while it was a beautiful instrument, when I fingered notes from D and C, I could really play any note. It just didn't center. I could force the pitch down, like I was settling into a trough, but there was no top to the trough, and it was odd. A good player would probably do fine with it, but after playing piston F's and various CC and Eb tubas, it bugs me. I also went to the B&S/Meinl Weston display, and to me, every rotary F tuba they made, while beautiful and generally a good player, had the very odd feel on the low C, just the same as 20+ years ago when I first tried them. Isn't anyone working on improving this?
Miraphone has had great success with their Firebird F tuba. While not perfect, the low C and surrounding notes do center in well. Their older 181 F tuba is not quite up to that standard, as it's similar to the B&S/MW F tubas. Many of which are based on the 181, so I hear. The model 180 is still funky though. I get it. It's a solo tuba. Still, I figure they'd look into this.
A few years ago I fell in love with the little red brass 3/4 F tuba from Cerveny, the model 753. It was fairly cheap, played low just fine, and had a big sound for a little tuba. I finally ordered one, but when I got it - you guessed it: wonky low C.
I've watched Kanstul make adjustments to the taper of his new tubas to solve some problems on the prototypes. He's been tinkering with the taper here and there, pinching the bore at a node, and it reminded me of another tinkering session.
When I was at Miraphone earlier this year, I tested the new 6/4 BBb tuba. It's awesome, but a few notes didn't center quite right. Markus Theinart thought maybe the bore was too big, and had some sleeves made to fit inside of some of the tuning slides. This would narrow the bore a bit, at least for some of the straight tubing. There would be some errors of course, but he thought it might help them see if they were on the right track. I have some video of this testing session I'll try to post someday.
All this leads to tonight. I'm in my office late, glaring at this Cerveny 753 F tuba which needs a dent taken out, and I looked closely at the bore coming out of the 4th rotor. The knuckle exiting the 4th rotor is oversize compared to the rest of the rotors, and then a large tuning slide sleeve is attached to the outside of that. The tuning slide sleeve is almost 6" (15cm) long, then on the other side of the tuning bow, there's another sleeve even longer. There's no nice way of saying it: there is some serious error of taper in this tuba. And not just this one. I pulled up some pictures of other rotary F tubas, and they all have this straight sleeve right after the 4th rotor. The only one that doesn't is the old Miraphone 180. It has a loop after the 4th rotor, like a 186 CC tuba. But it fails down low too. Obviously there's some error there as well.
I think that's the problem. There's an error in the location or size of the straight tubing after the rotors. So what about tapering that tuning slide sleeve on the Cerveny? Or perhaps just making it smaller would do. I don't have any extra brass tubing to insert in there, but I remember an old product, a tube made of thin plastic, that slipped inside a trombone tuning slide sleeve to adjust the response. So I made one for this Cerveny. Some Trader Joe's chocolate covered raisins in a plastic box next to my desk were promptly eaten, and I cut a little square out of the plastic, about 2x2" (5x5cm). I rolled it up, and stuck it inside the tuning slide sleeve, right at the end where it butts up against the 4th rotor.
It was a plastic box like this. Who knew it was perfect for making little shims to roll up and place inside the tuning slide:
Here is the cut up box, some shims, scissors, and a probe to remove errant shims:
And you know what happened?
This Cerveny has a roaring low C! I fooled around with different sizes and placement of my rolled up plastic squares, and found a place that seems to fix the C, but doesn't affect other notes much or at all.
Think how much better this might work if I actually get a short sleeve of brass tubing to fit in there.
The plastic shim ready to be installed:
The shim inside the tuning slide sleeve. The best position was with it pushed all the way in:
Here's a closeup of the step up in bore from the 4th rotor to the tuning slide. Somewhere after this point is the low C error:
The offending Cerveny. Notice how long the tuning slide sleeves are. Some other F tubas are similar:
As I type this, I'm playing with an old Miraphone 180 F tuba I have here. It's not just any 180, it's Roger Bobo's, with one with the Besson bell on it. Its low C is OK, but it could be better. I'm actually having some success on this one too, by placing the little sleeve in the small side of the tuning slide.
Could it really be that I'm solving an age old tuba problem for the price of a plastic box of raisins? (And I still get to eat the raisins.)
Protip: I have a little poker, pictured above, sort of like a sharp bicycle spoke with a bend at one end, so I can catch the edge of the plastic shim and pull it out. Without this, I might be sad.
So, has anyone tried this, either with the shims like I made, or piece of tubing? Has adding a small amount of (rough) taper to the straight portion of your horn improved it? More importantly, why haven't the makers of $10000 tubas been playing with simple ideas like this to improve their designs?
Steve (who looks forward to receiving abuse from tubists who have little squares of plastic stuck inside their horns) Ferguson
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