Piston vs Rotors observation, and the dreaded low C

[russiantuba]

As I get older, I feel I have a better (not amazing) sense of pitch center--more in terms of playing "in tone" and how that is as important if not more than playing "in tune".

With that being said and the Rotor vs Piston post, I have not had as many low C issues on rotor F tubas I have played. Granted, I play a piston F and have owned both, when I have played students horns after months of not playing a rotary instrument, I am able to easily center the low C and point and shoot, and I think it hit me and has been referenced here in passing.

Rotor tubas take whatever you give it in terms of the "buzz" or pitch center. If you don't have a sense of pitch, it will sound and play stuffy. Piston tubas I feel hide a lack of center more, but as you get more control, I start finding them harder to play in the lower registers than the rotor counterpart. Basically, rotors aren't as forgiving but also serve as a truth detector.

Your mileage and experience may vary.

[donn]

Apologies in advance, I probably missed this somewhere in the extensive discussion of this topic, but ... why?

I mean, these are valves that connect / disconnect some auxiliary tubing. One valve revolves around an axis, the other passes back and forth along a straight cylinder. Do we know how this simple mechanism exerts such a dramatic, predictable influence on the playing characteristics of the instrument?

Or is it a coincidence of some other "confounding" factor that tends to be correlated? For example, I suspect rotary valves are often installed farther along towards the large end of the "bugle", making the final "conical" section a little shorter relative to long cylindrical sections (4th valve), maybe enough to make trouble at some critical point that coincides with your low C.

[russiantuba]

I do think it is the “stovepipe” design—hence why I mentioned in the other post about the Bruckner feeling like the same horn. But having the rotors further down on the bugle I think mandate that all pitches have to be exact as the change is later—I have nothing to back this up.

[Mary Ann]

Based on the "dent" phenomenon and being an engineer, if an instrument does not have nodes where it needs to have nodes, there will be some notes that don't "want" to easily play. Obviously many overcome that, but my amateur observation is that somehow the shape of the wrap (?) somehow makes the nodes appear magically in the piston Fs where they do not just as magically appear in the rotaries. Even the NStar has a bit of that in the low range, but it is much more easily overcome than on most rotary Fs. Friend has a Firebird, and even after the NStar I came to pretty much a screeching halt on the low C on it; yet he has no problem. He also is a big tuba-sized guy. I guess you just power through those once you figure it out. Once it's figured out, it seems it can't be taught, "neither," and each successive person has to do their own figuring.
I did play an older Symphonie once (Mark Nelson's) and noted much less problem with its low range, for me.

[donn]

I guess a little engineer talk wouldn't hurt anyone, or hardly anyone.

My question about this: what is it about the sound wave node? Is that really functionally significant, or really more of a representational feature of a phenomenon that's really equally sensitive or insensitive to disturbance along its whole length? At a casual read, the node is where the reflected sound wave cancels the air vibration; the anti-node between the nodes is where it reinforces. At this rather elementary level, it isn't obvious to me that the node would be any more significant in this matter, than an anti-node or any other point in the system. Or maybe it would be the least significant place, having the least vibrational energy to disturb, and the anti-node the second least; the worst would be a disturbance at some intermediate point with the potential to locally shift the node/anti-node structure.

[donn]

Also, if you go to the right repair person, braces can be added and removed to address the problem.

We had a guy like that in the strings business, who retired from aerospace engineering to work on violins and string basses etc. He developed a system of detecting vibrational aspects of the soundboard, by subjecting it to mechanical vibration with iron filings or something sprinkled on top. The particles would aggregate along some kind of nodal contours, reflecting the acoustical characteristics of the soundboard. I think this got written up in some popular science publication, but oddly I don't know of anyone else ever pursuing it. (Also, I was cautioned by someone who knew a lot of local players, not to ever let this guy do his thing to my bass, if hypothetically I were ever to have one with a solid top anyway.)

[Mary Ann]

There was an article in Scientific American a long time ago, about this. My understanding is that they analyzed some ancient and fantastic instruments to see what the characteristics were, and then applied those to new instruments to "see what would happen." What has happened is that there are now violins being produced in this country that are better than Strads. I have heard one of them and know it is not hearsay. It wasn't the varnish, or the age, but how the wood responded to the vibrations, which could be messed with by a person of intelligence and technique, to make a new one respond as well or better. Probably the characteristics of the wood matter.

[Sousaswag]

I played some of the new Lidl models today at Buddy Roger’s, and will post about it later.

My point:

The low C played just fine. I think design plays more into it than anything. Both models had the same body, and both had a perfectly fine low C.

The newer instruments just have better designed bodies and branches, I think, that make that low C less of an issue.

[catgrowlB]

Probably the best rotor F tuba I played (many years ago) was a Rudi Meinl 5rv F. It played and sounded like butter, top-to-bottom. No problem with the low C register. Just tooting on it at a tuba conference. I was amazed at how well it played!

Conversely, several years later, I bought a piston Meinl-Weston 45slp, silver-plated. It was a nice early model that had the mouthpipe floated around the bell. It played very well, but didn't center the low C register as well as some other F's. It was a very open sounding/playing tuba with a few pitch oddities. The second valve trigger is needed on those. Sold that tuba back in 2009.