Bass Trombone Rotor Direction

[PSJ]

I know this is a weird subject title but I am not sure how else to word it.

I have an Olds P-24G that I would like to play more but the ergonomics of the factory triggers are not good. When looking at options for a new trigger set-up, one might be to change the rotational direction of the F trigger from counter(anti)-clockwise to clockwise.

So my question is, does the rotational direction of the rotor matter on an independent rotor bass trombone? If it does, what are the reasons or explanation for this. I am interested for this project and just plain interested in general.

I am hoping maybe some of the instrument builders, long time players, or anyone with knowledge might chime in on this!

Thanks;

[Tooloud]

Being just part time bass trombonist I spend most of my time playing on the french horn.
And there you might have opend a can of worms - it's almost a religious issue.

But to summarize al those endless discussions on french horn sites:
It simply does not matter!
There is a swish, no matter if the valve rotates with or against the airstream.
On my Alexander 103 the first two valves rotate in one direction, the third in the other. And it has been so for well over a hundred years - nobody cares....
So on a far less delicate instrument used for far less delicate exposed solo moments like the bass trombone:

It simply does not matter!

[hornbuilder]

Yes, the direction of rotation does matter. Yes, there is always "some" noise in transition (there has to be, simply because there is a change in tubing being used) The difference is in the "amount" of noise created in that transition.

On a valve rotating counter-clockwise on activation, the ports in the rotor are changing from one to the other. However, on a rotor that rotates clockwise, the port directing the sound stays the same, in both open and activated position. The sound path is simply being "re-directed", as opposed to the airstream/sound path being "cut" by the rotor transitioning.

You will notice a definite improvement in the smoothness of the slur into and out of the open/valve sides of the horn.

[Tooloud]

All you need to know: https://www.wienerhorn.com/forum/viewto ... f=4&t=1469

Result: It does not matter - at least in real life....

[Kbiggs]

All you need to know: https://www.wienerhorn.com/forum/viewto ... f=4&t=1469

Result: It does not matter - at least in real life....

I wish I read German, or could get a good translation.

It might not make any difference with French horns, but I’m with hornbuilder on this. I’ve played trombones where the valves were setup counter-clockwise vs. clockwise. I found that clockwise direction works best on trombones. There is much less “pop,” and it’s easier to get a clean valve legato.

[hornbuilder]

All you need to know: https://www.wienerhorn.com/forum/viewto ... f=4&t=1469

Result: It does not matter - at least in real life....

I don't know why I bother sometimes.

[Dennis]

I don't know why I bother sometimes.

Perhaps because some of us do appreciate what you have to say?

So, I have two other questions in relation to this: is it even possible to change the rotation direction of a rotary valve without a significant remodel, like creating a new bumper plate as well as new linkages?

And second, isn't there always a tradeoff--if the valve is not cutting the airstream when it's switched from open to engaged doesn't it necessarily cut the airstream when disengaged? As I visualize this it seems to me that's what has to happen.

[hornbuilder]

Thanks Dennis.

Yes, it is possible to change the direction of the rotation of any rotor valve. That isn't to say it is a simple task though, depending on the design of the horn.

Re the second part. No, the change back to the "open" position does not "cut" the airstream any more than on the activation stroke, on a valve that rotates correctly. It does cut both times on a valve that does not rotate correctly. (Wish I had diagram drawing skills to demonstrate)

[IdoMeshulam]

As it so happens, Brad Close did the exact modification you're talking about to my Olds P-24G a few months ago. New levers and linkages for better ergonomics and yes, he also reversed the rotation of both valves. Transitions between notes are definitely smoother now and it's comfortable and reliable for day to day use. Can't say it was cheap but IMHO totally worth it.

Here are some before and after pics:

[GabrielRice]

I can say from experience that it definitely matters.

And if there's anybody who knows - in real life - it's Matthew (hornbuilder), who both builds and plays bass trombones at a world-class level.

[LIBrassCo]

Yeah, this one matters.

[PSJ]

So far thank you for the replies. Especially the pictures. I had a S-24g in college many many years ago and Larry Minick fixed the trigger set-up. Unfortunately I don't have pictures or remember if the rotation direction was changed. 45 years ago I didn't think about these sort of things.

Please keep the input coming, and Matthew, thanks for your input!

[BGuttman]

Just want to put a little context to this.

If you just started playing a trigger trombone, it won't matter.

If you have a fair bit of time playing a trigger trombone, you will feel the difference. Will you hear it? probably not.

If you are playing an instrument with an undersized rotor, you will feel it more.

If you can earn your living playing a trigger instrument, you may even hear the difference.

[Tooloud]

If you can earn your living playing a trigger instrument, you may even hear the difference.

About 90% of French Horn played in european orchestras are Alexander - mostly 103 -, Engelbert Schmid, Dürk, add some Ricco Kühn and Fehr - in this order I think. None of those makers think that it would make any difference.
If it would really make any difference those 'inferior' but very expensive horns would not be exclusively used in top tier orchestras. At Berlin Phil using an 103 is mandatory.
If the sound or the playing would be notably better, there are horns available from Paxman, Cornford or Schmiedhäuser, where the valves rotate against (!) the airstream, which Prof Steidle thought to be advantageous.
But they are selling very small numbers, mostly because these instruments are really very, very well made high quality horns, not because of the direction of rotating valves.

Snake oil. But everyone believe what he wants to believe.

I do not eben know in which direction the valves on my bass trombones rotate - the valves on the bass trombone just are "Umschaltventile", not "Spielventile" -their role has the slide on the trombone and should be used preferably.

[hornbuilder]

[Doug Elliott]

Does anybody know what Steve Shires did with his French horn valve direction and what is thought of his horns in the horn community?

I the past 50 years there has been tremendous experimentation and innovation in trombone valve designs. In the horn world, especially in Europe, I suspect it's all about tradition.

How about rotary tubas?
I would bet it makes more difference as the valve gets larger.

[hornbuilder]

Edit.

[GabrielRice]

Does anybody know what Steve Shires did with his French horn valve direction and what is thought of his horns in the horn community?

There are not a lot of Stephens French horns out there, since he is building them himself. A handful of colleagues of mine are playing and loving them.

He has two different wrap designs, as you can see on his website: https://www.stephenshorns.com/horns

Series I
The Stephens Series 1 Geyer-model horn is designed to offer the essence of a classic Geyer horn but with a more even response and intonation. Wrapped up like a traditional Geyer Horn, it features a clear, open sound that also has depth and character missing from some modern instruments. High quality German valves are used. They are airtight, assuring a good response and even slotting. The action is quick and reliable.

Series II
The Stephens Series 2 model is a wrap that is far less common in the horn world. It is designed to have the comfortable ergonomics of our Series 1 “Geyer” model, but to also include aspects of the classic “C. F. Schmidt Horn. Some players find an uncomfortable “blip” in the sound when switching off between the Bb and F horn. This effect results from the air stream reversing direction when the fourth valve is utilized. Like classic Schmidts, the Series 2 horn has air pass trough the horn the same direction on the Bb and F horns. The F loop wrap is before the valves, as it is on a Schmidt as well. This allows for a particularly even instrument that can achieve remarkably smooth slurs.

[GabrielRice]

My own experience:

For a while I had a bass trombone that had been custom built with Meinlschmidt Open Flow valves. The default from the factory, without changing the stop arms, was that the F valve turned clockwise and the G-flat turned counterclockwise.

This caused a problem when going from two valves to one in legato. The new Meinlschmidt valves were so tight that the compression would often cause the 2nd note not to speak at all. Moving more air (playing louder) made it worse. Having the direction of the 2nd valve reversed solved the problem.

My guess is that the valve turning in the opposite direction of the air flow is much less of a problem with valves that are vented or just generally looser.

[Doug Elliott]

How about other American made French horns?

Tubas?

[pfrancis]

To Doug’s question about larger rotor instruments - lots of tubas including many B&S/Miraphone/Meinl-Weston redirect the air in the same fashion as people seem to prefer here. Gets a bit funny to talk about as the air runs in a “different direction” from bass trombone. Basically the active port is continually in use, rather than interrupting the air by “chopping” the air with a passing rotor face. I agree with Gabe, on valves instruments this matters less when they are vented - no allowing for any pressure to build.

I think where this difference is best realized is when going from 6th or 7th position (on F att.) to an inner position out of the valve. If the valve rotates anti clockwise it will make a ln audible pop as the air pressure builds briefly. That is, unless there is an accommodation for air to pass by in the middle of the stroke.

FWIW it’s a very easy swap on a Yamaha 613H, did so on mine with a replacement stop arm and a new bumper plate screw hole drilled/tapped for new orientation. I like it better than original factory spec. This is one of the differences from 613H to 830/835.

[hornbuilder]

The difference between French Horn/tuba and trombone, is that the instrument has valves from the very beginning of playing that instrument. So players don't even think about the fact that the valves create a disconnect (of varying degrees) in the sound during transition.
Trombones on the other hand, start out playing straight/valveless instruments. That is why the Thayer valve was invented. To recreate the "straight horn feel" on a valved instrument.

Horn and tuba players "expect" added resistance when adding valves. It's a feature of the horn. Trombone designers have been doing everything they can to make the difference as little as possible since the valve was invented.

[tbonesullivan]

FWIW it’s a very easy swap on a Yamaha 613H, did so on mine with a replacement stop arm and a new bumper plate screw hole drilled/tapped for new orientation. I like it better than original factory spec. This is one of the differences from 613H to 830/835.

Yes, and it was literally one of the big "improvements" they touted in the launch video for the YBL-830. The others were the Nickel Silver End bow on the slide, the extended range of the 2nd valve tuning slide due to removing the ability to play in Bb/F/G/Eb tuning, and a few other things.

I'm honestly kinda curious as to why they had the valves moving the opposite direction in the first place, but it was most likely because the YBL-613 and some other horns that preceded the YBL-613H were that way. Yamaha tends to keep things identical until they get a real reason to change them.

I just took a look at lot of older horns, and having counter clockwise rotating valves was not exactly a rare thing. Holton basses I think always had the F valve rotating counter clockwise until the TR181.

[Crazy4Tbone86]

I became fascinated with this topic after seeing a Yamaha video about the changes in their bass trombone design. Yamaha changed to a clockwise rotation many years ago, citing acoustical advantages. After seeing the video, I remember questioning it and having exchanges with several custom trombone makers (including Matthew) about the topic. Most agreed that the clockwise rotation was better.

Having played mostly Bach rotary valve horns over the past decades, I was already playing instruments with a clockwise. I thought “why not put it to a test?” I decided to change the linkage on one of my Bach 42Bs (so it would work on both sides of the spindle screw), drilled and tapped another set of holes in the rotor casing which allowed the cork plate to be flipped to the other side, and modified the stop arm so that it could be reversible as well. The end product was a rotor that was completely reversible but had the same function (B-flat side when not engaged and F-side when engaged) on both sides. The only difference was the direction of rotation. The original was clockwise and the new option was counterclockwise.

While play-testing the instrument, I noticed that marcato passages played and felt the same with the rotation going either way. However, there was a difference in how the legato/slurred passages felt with the valve. The clockwise (original for Bach) was definitely smoother and easier. When slurring with counter-clockwise rotation, there was more of a pop. The pop was enough that I felt the need to “cover it up” with a legato articulation. In other words, I was not 100% comfortable doing a natural slur with the valve.

I wish I still had that horn because I thought it was a cool experiment and concept. I sold it to a guy who lived outside of Philadelphia. If he is on TromboneChat, I would hope that he could show photos of the valve area.

I don’t think this is snake oil in any shape or form. I believe it is a matter of how picky musicians are about how their instruments play…..at least the trombone. This discussion is very similar to the slide crook guard rubber bumper. Some believe the presence of a rubber bumper makes no difference…..I happen to believe it makes the horn play differently.

Doug brought up a good point…..does the rotor rotation direction impact larger instruments more? Possibly? I know of a couple of tuba players who customized their rotary valves so that they all move the same direction (same concept as our “clockwise” direction. I would like to hear from Steve Shires on this topic. I am sure that rotation direction was an important consideration when he was designing his horns (French horns).

[pfrancis]

Brian, used to be that many tubas had valves 1 & 2 on the opposite side of the spindles as compared to 3 & 4. Modern horns have basically all moved to the increasingly popular “clockwise” side - though as I mentioned, on most tubas it isn’t clockwise due to wrap orientation. Haven’t really thought about how this is bore out on piston tubas with only a fifth rotor.

[Crazy4Tbone86]

The difference between French Horn/tuba and trombone, is that the instrument has valves from the very beginning of playing that instrument. So players don't even think about the fact that the valves create a disconnect (of varying degrees) in the sound during transition.
Trombones on the other hand, start out playing straight/valveless instruments. That is why the Thayer valve was invented. To recreate the "straight horn feel" on a valved instrument.

This is a very valid point. As trombone players, we do have very different expectations of our valves, which is based on the feel of doing most of our pitch and articulation manipulation with a slide.

I have a very different expectation of the valves (even though they are pistons) on my trumpets and euphoniums. I expect those valves to “pop” the note into place and have a much tighter slotting.

[Crazy4Tbone86]

Hey Pete,

Was not aware that most tubas have gone that direction. I have only worked on one German tuba in recent months and it had all 4 rotors going “clockwise.” I just thought it was an anomaly.

To me, the fact that tuba makers are changing their rotor rotation direction is a sign that they see it as a favorable design. After all, they wouldn’t invest in design and tooling changes if they thought it was “snake oil.”

[hyperbolica]

This is going to sound like a stupid question to some people, but words like "clockwise" and "counterclockwise" are only valid given a common context. You know which way you're supposed to look at a clock (toward the face so that the numbers are readable), but there is no equivalent context for trombone valves. I've seen horns with valves that point in both directions (core spindle toward player or away from player). So what frame of reference is it that establishes CW vs CCW?

[GabrielRice]

Actually, there are spindles on both sides.

Stop arm/lever side. Though there are probably rotary valves somewhere in the universe that put the stop arm and lever on the other side.

[harrisonreed]

This is going to sound like a stupid question to some people, but words like "clockwise" and "counterclockwise" are only valid given a common context. You know which way you're supposed to look at a clock (toward the face so that the numbers are readable), but there is no equivalent context for trombone valves. I've seen horns with valves that point in both directions (core spindle toward player or away from player). So what frame of reference is it that establishes CW vs CCW?

The spindle/stop arm side is called the "front". The valve cap is the "back".



This guy uses good terminology in a very good video about rotor disassembly.

[Doug Elliott]

Another question: what about pistons? Are the valve ports arranged so the flow remains the same direction, or does it switch direction in some?
I haven't looked yet...

[PSJ]

The above question is the next thing I was going to ask. I have been looking at the spindle end with the bumper and stop arm.

Of course after mentioning tubas I had to go check my Cerveny Eb, 1 and 2 are counter clockwise and 3 and 4 are clockwise. Also checked my early Abilene Conn 71H clockwise and my Benge 175F clockwise.

To Ido, thanks for the pictures of your P-24G! I am showing those to my repair/custom horn guy tomorrow.

I didn't want to open any can of worms with this question, really was interested. I guess as I get pretty close to retirement I am having too much time to think..........

[tbonesullivan]

This is going to sound like a stupid question to some people, but words like "clockwise" and "counterclockwise" are only valid given a common context. You know which way you're supposed to look at a clock (toward the face so that the numbers are readable), but there is no equivalent context for trombone valves. I've seen horns with valves that point in both directions (core spindle toward player or away from player). So what frame of reference is it that establishes CW vs CCW?

I guess, looking at the valve such that the lower left knuckle is the source of the incoming air / vibration stream. For a trombone this would be looking at the left side of the trombone, where in most cases the spindles and linkages are. I'm sure there is a more accurate way to explain it for other instruments, but I can't think of one right now. It mostly has to do with one direction of rotation having a smoother transition into the valve being actuated. With "counter clockwise" the air stream gets almost completely interrupted at one point in rotation.

[Tooloud]

So, back from the practice room: I tested the topic on my french horn using the most lyrical piece I found on my stand: Mahler's "Urlicht".
This is, what I found:
Using the first two valves on the Bb-side, which - according to he opinion here prefered - turn in the correct direction:
Yes, the slurs form open horn to an engaged valve are smoother. (pp, slow tempo)
But: If I play from an engaged valve to the open horn, there it is, the 'ft'.
So, on a valved instrument it does not matter in the end.

But I do admit, that on the trombone, where we use the valves differently, it may have an effect.

[Dennis]

Thanks Dennis.

Yes, it is possible to change the direction of the rotation of any rotor valve. That isn't to say it is a simple task though, depending on the design of the horn.

Re the second part. No, the change back to the "open" position does not "cut" the airstream any more than on the activation stroke, on a valve that rotates correctly. It does cut both times on a valve that does not rotate correctly. (Wish I had diagram drawing skills to demonstrate)

Thanks, Matt. I'm going to have to do some sketching when I get home.

[pfrancis]

Hey Pete,

Was not aware that most tubas have gone that direction. I have only worked on one German tuba in recent months and it had all 4 rotors going “clockwise.” I just thought it was an anomaly.

To me, the fact that tuba makers are changing their rotor rotation direction is a sign that they see it as a favorable design. After all, they wouldn’t invest in design and tooling changes if they thought it was “snake oil.”

I specifically kept quotes on things because these labels are troublesome. I would suggest that any accepted nomenclature should refer to either: how the rotor directs the air into the tubing OR chopping it as it changes orientation - with a rotor face/spline interrupting the flow by passing by. On trombones the tubing is on the opposite side of the valve as compared to most tubas - based on the other unique body/instrument parts. If it were on the same side as tuba the wrap would be sticking out/through the players neck…

As for tooling changes, not much changes when the valve rotates in a “reversed” fashion, mostly smaller components (levers, linkage etc). Wraps can be the same and the rotors are not generally obviously modified either.

[Sesquitone]

Here are some (rough) sketches of a standard (sculpted butterfly) rotary valve showing clockwise and counter-clockwise rotations.

For CW rotation, provided gaps A and B open before gap C closes, there is no cutoff of the air-flow path.

For CCW rotation, provided gaps D and E open before gap F closes, there is no cutoff of the air-flow path.

Since the CCW rotation intermediate orientation is a mirror image of the CW case, with arrow directions reversed, there is no (theoretical) difference between the two cases.

For smaller-bore knuckles (and same casing diameter), the respective "gaps" will be smaller, causing more "swishing"—or the dreaded "pfft!". Or possibly complete blockage-and-release, causing "popping". The latter is the reason that intact-duct designs must be vented—either by providing vent-holes or (more commonly with recent designs) using lipped-tubes (Greenhoe, CAIDEX, ULTRA). Even on sculpted butterfly designs, a lipped-channel can give additional venting (Meinlschmidt). In all such cases, the transition is absolutely "pfft!"-free.



.

[Kbiggs]

A question out of ignorance: When discussing rotary valves, whether they are traditional “butterfly” valves or a more modern intact-duct valve, and avoiding pop and pfft, are we talking about the sound waves traveling through the instrument, air flow, or balancing air pressure pre- and post-valve? Perhaps something else?

[Sesquitone]

A question out of ignorance: When discussing rotary valves, whether they are traditional “butterfly” valves or a more modern intact-duct valve, and avoiding pop and pfft, are we talking about the sound waves traveling through the instrument, air flow, or balancing air pressure pre- and post-valve? Perhaps something else?

Air flow only. The standing waves producing the (desired) sound are independent of the air flow.

[hornbuilder]

Some of us talk theoretically.

Some of us talk practically.

[AtomicClock]

Some of us talk theoretically.

Some of us talk practically.

Are Sesquitone's sketches not what you had in mind?

(Wish I had diagram drawing skills to demonstrate)

[Sesquitone]

A question out of ignorance: When discussing rotary valves, whether they are traditional “butterfly” valves or a more modern intact-duct valve, and avoiding pop and pfft, are we talking about the sound waves traveling through the instrument, air flow, or balancing air pressure pre- and post-valve? Perhaps something else?

On well designed valves (of any type) in either active position, the air flow is laminar with very little pressure drop. Standing waves (bouncing back-and-forth at the speed of sound) are not affected by this slowly moving air. During transition, a poorly designed valve becomes a series of little orifices, first causing a pressure drop across each orifice, and then sudden restoration of laminar flow and equalisation of pressure. The rapidly changing pressure causes the "swishing" or "pfft!" sound—exacerbated by an inward-moving slide causing higher air-flow speed. Although there is no "theoretical" difference between the CW and CCW rotation directions of rotary valves regarding air-flow paths, the differing local "orifice effects" could account for the practical difference evidently experienced by (some) players.

Venting, especially using lipped tubes (e.g. Greenhoe, CAIDEX) or lipped channels (e.g. Meinlschmidt), provides for ample air flow around the outsides of the tubes/channels during transition, with no pressure drop/restoration, thereby completely eliminating the "orifice effect"—guaranteeing "pfft!"-free legato valve action (regardless of a moving slide).


.

[hornbuilder]

Some of us talk theoretically.

Some of us talk practically.

Are Sesquitone's sketches not what you had in mind?

(Wish I had diagram drawing skills to demonstrate)

No. An animation, which I have zero ability to create, would show things much better than static drawings

Again. I have actually done the physical experiments. Similar to what Brian wrote about above. The rotation direction of the valve absolutely makes a difference in the amount of noise induced in transition, regardless of valve type!

[ZacharyThornton]

Some of us talk theoretically.

Some of us talk practically.

That sums up a lot of what goes on here. People who think they know acting like the have the same level of experience of people who do know. “Death of the expert”.

[heldenbone]

My first reflection this was that "of course it matters, ESPECIALLY on bass trombone. The standing wave is oscillating far more air back and forth, and there is no hand stuffed in the bell disrupting the acoustic transition of the bell from low cross-section and high impedance to the room's essentially unlimited cross-section and no impedance." But, I freely admit to not being an expert of any sort.

[elmsandr]

That sums up a lot of what goes on here. People who think they know acting like the have the same level of experience of people who do know. “Death of the expert”.

Nah. A false dichotomy as well as an “appeal to authority” as a classic logical fallacy.

You need both. You need to have a theory “I think X because Y” that allows you to test “Y1 is better than Y2 and I can measure that by Z”. This is how good design end engineering is performed. Heck, especially with imperfect measurements or opinions of “Better”, I would expect that a very significant number of tests to come back inconclusive or with even the generally wrong answer. {‘but I’ve tried it and I disagree’ is a very valid and appropriate response, and could even cite very real data!}. It isn’t the role of experts to all agree. Especially when the results aren’t as simple as something that can have a quick physics sketch with a very clear “right” answer.

For example, in this discussion, one could reference the discography of folks playing old Holtons and note all the times going into and around the valve registers with their F valves that rotate the wrong way to show that there is nothing wrong with the rotation. Heck, those old Dave Taylor recordings are some of my faves and his transitions sounded better then than mine will ever sound. So is my theory wrong, or is the measurement of my ears imprecise, or was the effect small enough that it isn’t detectable? Or maybe something else entirely, but I hope I’ve made a basic point. (Also note here that he seemed to like that rotation enough that the old Getzen 1062’s had their F valves rotate that direction). If one still insists that practical experience of a master should be deferred to, would that not be sufficient evidence to say not only does it matter, but the opposite direction is actually better? For me, I still prefer the more common rotation direction and I think it was a good thing when they updated the Getzen 1062 as well. I remember complaining about this to Christan a couple of decades ago now… and I wouldn’t have called myself an expert then, just a kid wondering why it was different and noting that it felt different than my Bach.

Returning to the topic but pivoting a bit…. How do we feel about the rotation with respect to Axial valves? Every bass set I’ve seen (except one) has the rotors going in opposite directions, the air and sound path is getting extremely ‘chopped’ here, I’d say especially by the second valve… I’ve always wanted to rethink the standard bass 2 valve layout of the Thayer, but my concern was always more about neckline length than valve interference, but my theory is lacking and this would involve a lot of work to test.

Cheers,
Andy