The physics of extending rotary spatulas.

windshieldbug · Post by **windshieldbug** » Wed Oct 18, 2006 10:27 am

Allen wrote:Of course, we don't have to stop there. How about an automatic (microcomputer-controlled) mechanism to pull slides? Every tuba can have perfect intonation!

Ah, there's the rub- Perfect intervals, Equal Tempered, Pythagorean, Meantone, Just, with what base as a start, along with the harmonies behind... I think your "simple" system just got a lot more complicated than just using your ears and push/pull!

Allen · Post by **Allen** » Wed Oct 18, 2006 11:51 am

windshieldbug wrote:
Allen wrote:Of course, we don't have to stop there. How about an automatic (microcomputer-controlled) mechanism to pull slides? Every tuba can have perfect intonation!
Ah, there's the rub- Perfect intervals, Equal Tempered, Pythagorean, Meantone, Just, with what base as a start, along with the harmonies behind... I think your "simple" system just got a lot more complicated than just using your ears and push/pull! :shock:

I'm making nice deranged suggestions, and all you're seeing is problems! Of course tuning is complex. Just think of all of the software development opportunities that makes. And the best feature is that you can blame the computer for all mistakes. [Of course, the software developers will blame the users for not using the software correctly.]

It seems to me that people are using mere practicality to get in the way of the spirit of true innovation.

Cheers,
Allen
[Now I'll remove tongue from cheek.]

windshieldbug · Post by **windshieldbug** » Wed Oct 18, 2006 12:21 pm

Allen wrote:Just think of all of the software development opportunities that makes

Sharp - Operator error.
A â‰ 440 - Next release.
Flat 5th partial - Feature.

iiipopes · Post by **iiipopes** » Wed Oct 18, 2006 1:37 pm

All sorts of actions have been tried on pipe organs; if physical placement due to the size of the instrument or location of the architecture are not an issue, a lot of manufacturers have gone back to direct mechanical linkage tracker: overall easier to maintain, lasts longer, less extra parts to break, and control over intonation and shading that does not exist with other forms. As far as servo mechanisms: Reynolds had one on the 1st valves of tubas and other low brass for awhile with a spring return mechanism @ 1958, so you could push in for 1st valve second space C on a BBb tuba as well as pull out for 1-2 and other multivalve combinations. It lasted about as long as it took to print the brochure that described it.

Allen · Post by **Allen** » Wed Oct 18, 2006 5:13 pm

iiipopes wrote:All sorts of actions have been tried on pipe organs; if physical placement due to the size of the instrument or location of the architecture are not an issue, a lot of manufacturers have gone back to direct mechanical linkage tracker: overall easier to maintain, lasts longer, less extra parts to break, and control over intonation and shading that does not exist with other forms. ... ...

If you should try saying that on a pipe organ BBS, you'd start a bloodbath. Every item would be disputed, with quotations of Higher Authority as well as definitive personal observations. It would make our frequent debates like BBb versus CC or rotary versus piston seem like genteel agreements.

Although opinions on pipe organ mechanisms aren't appropriate on this BBS, I have the courage to offer one anyway. Here it is: "It depends." [This does seem familiar. Have I read it somewhere on this BBS?]

Cheers,
Allen

iiipopes · Post by **iiipopes** » Wed Oct 18, 2006 8:02 pm

Let's see: I've been on three pipe organ committees, authored a paper that established a foundation line item for the tuning and maintenance of the pipe organ at my undergrad (a rare Lyon & Healy, made during the very few years they made pipe organs from scratch as well as their famous harps), rewired the relay to one of the two chambers of a Morton 3-manual, now donated by the estate of the owner to a local theatre restoration, scraped untold number of leather gaskets and releathered them to the impregnating aroma of fish glue, was the defacto 2nd guy to a long time independent tuner/repairman who used to take care of most of the pipe organs in the area, almost had a 3-rank unit organ installed in my house, then my job changed and I had to move and a church got it (and I got a deduction!) etc. Yes, I know the bloodbath my statements could start. I stand by them.

iiipopes · Post by **iiipopes** » Thu Oct 19, 2006 1:50 am

Hey montre8 -- I agree totally. But, damn the smell of fish glue!

Anyway, considering not only the length of the spatulas, but the overall system, does anybody have any experience they would like to relate about playing a Hirsbrunner compensating rotor tuba as described here, especially how the double decker rotors compare with conventional rotors? Since rotors are theoretically suspended in the casing and not as prone to touching it as pistons, there shouldn't be much difference, but I'd love to know. Here:

viewtopic.php?t=15662&highlight=hirsbru ... g+rotor%2A

Rick Denney · Post by **Rick Denney** » Thu Oct 19, 2006 4:43 am

iiipopes wrote:Anyway, considering not only the length of the spatulas, but the overall system, does anybody have any experience they would like to relate about playing a Hirsbrunner compensating rotor tuba as described here, especially how the double decker rotors compare with conventional rotors? Since rotors are theoretically suspended in the casing and not as prone to touching it as pistons, there shouldn't be much difference, but I'd love to know.

I once played a prototype Miraphone with automatic compensation taht used double rotary valves, and didn't feel much difference.

But the mass of the rotor does have an effect on the inertia of the system. The extra weight of a lengthened spatula would be nearly insignificant by comparison, I would think.

I also once owned a Sanders/Cerveny that had hollow rotors. The valves on that tuba were really quite fast.

Putting the limit stops at the finger end of the linkage instead of on the stop arm so close to the rotor shaft would increase precision and positive feel (without needing hard rubber), and would allow designs with much greater adjustability. It would require linkages with very little play. Say what you will about my model airplane ball joints, they have nearly no play.

It would be fairly simply to construct a stop rail to be mounted below the finger paddles with screw-adjustable stops. The stop would bear on the underside of the paddle for the downstroke, and on the linkage near the ball joint for the return stroke.

Rick "who thinks rotor-shaft-mounted stop arms are an artifact of string linkages" Denney

windshieldbug · Post by **windshieldbug** » Thu Oct 19, 2006 5:53 pm

Yet another system of stops: on the rotor arm itself!

Combined with adjustable tension clocksprings...

TubaRay · Post by **TubaRay** » Thu Oct 19, 2006 5:55 pm

windshieldbug wrote:Yet another system of stops: on the rotor arm itself!

Combined with adjustable tension clocksprings...

Nifty!

iiipopes · Post by **iiipopes** » Fri Oct 20, 2006 2:00 am

Now THAT's cool! What company made this fine relic that should be reexamined for contemporary use along with the newer ball linkages?

cambrook · Post by **cambrook** » Fri Oct 20, 2006 2:42 am

I like Rick's idea a lot, it makes perfect sense and as soon as I read it I wondered why it hasn't been done before. Well we actually know the answer to that - what exists works OK so there isn't any major pressure to come up with an improvement. Still, that doesn't mean that things can't be better than they are.

As I was redoing the corks on my valves the other night, having to carefully trim shavings off to get the alignment right I was dreaming of a plate with adjustment screws to be able to put the stoppers in the correct place. Ricks idea is better than that, now that excellent ball joints are in use play in the pivots is almost non-existent.

Chuck(G) · Post by **Chuck(G)** » Fri Oct 20, 2006 2:50 am

cambrook wrote:I like Rick's idea a lot, it makes perfect sense and as soon as I read it I wondered why it hasn't been done before..

I'm sure that someone's done it. Heck, if I can think of it, smarter people probably already have:

http://www.chisham.com/tips/bbs/feb2003 ... 23727.html

Rick Denney · Post by **Rick Denney** » Fri Oct 20, 2006 10:43 am

Chuck(G) wrote:
cambrook wrote:I like Rick's idea a lot, it makes perfect sense and as soon as I read it I wondered why it hasn't been done before..
I'm sure that someone's done it. Heck, if I can think of it, smarter people probably already have:

http://www.chisham.com/tips/bbs/feb2003 ... 23727.html

Heh, heh.

Rick "who knows a good idea when he steals it" Denney

windshieldbug · Post by **windshieldbug** » Fri Oct 20, 2006 11:55 am

iiipopes wrote:Now THAT's cool! What company made this fine relic that should be reexamined for contemporary use along with the newer ball linkages?

Wouldn't you know it, unmarked. eBay seller's guess is perhaps Cerveny.

windshieldbug · Post by **windshieldbug** » Sat Oct 21, 2006 11:44 am

This is a marked Cerveny flugelhorn, so it seems that it was a good guess.

Art Hovey · Post by **Art Hovey** » Sun Oct 22, 2006 11:41 pm

Here's a photo of the linkage on my "frugal-horn" project. Notice the location of the stop-pads and the unusual length of the lever arm on the rotor. It feels just like a piston valve when I am playing it.