Reversing a tuning slide?

[sirisobhakya]

I have seen some refer to “reversing a tuning slide”. My understanding is that this means making an existing, normal tuning slide with both inner tube on the tuning slide, to a reversed one with the gooseneck-side leg of the tuning slide being the outer tube.

That means a new part is needed, right? If there is no new part involved (like just unsolder the gooseneck side tubes and re-solder), the inner one is still smaller than the gooseneck ferrule, and there should be minimal benefit.

Please enlighten me on the subject.

Also, how big is the effect? I have play-tested some horns with reverse tuning slide and I cannot feel much difference…

[tbonesullivan]

The idea is that you get a "smoother transition" through the tuning slide area, though how much smoother it is, that's debatable. There is still going to be a wider portion where the slide is "open" regardless of whether it is a standard or reverse tuning slide. If you look down inner tuning slide, there usually is already a bit of a "bump" where the gooseneck and tuning slide inner join inside the ferrule, as the wall thickness of the tubing may be different.

If you want a truly smooth increase in diameter, a J bend with tuning in slide is really the only way. You always are going to have that "wider" bit where the inner has slide out from the outer.

Not to mention this is already what is happening in the outer slide. It's really just another thing for people to obsess over.

How this is accomplished depends on the instrument. But in general you need to at least switch the hardware and inner and outer tuning slides. You may also need to get new parts and/or cut some.

[brassmedic]

You would swap the neckpipe ferrule with the tuning slide ferrule and swap the tuning slide outer leg with the inner leg attached to the neckpipe. You may have to modify the parts a bit but normally wouldn't need new parts.

The idea is to eliminate the gap between where the neckpipe ends and the inner tuning slide leg begins. The problem is, if it was designed to be the same inner diameter from the tuning slide inner leg to the beginning of the tuning slide crook, then there will be a lip there after you remove that inner leg. So you're not eliminating the gap, just moving it further down.

A true purpose built reversed tuning slide would have the inner diameter of the outer tuning slide leg match that of the crook. That way you have no gap, only an expansion.

[Sesquitone]

Also, how big is the effect? I have play-tested some horns with reverse tuning slide and I cannot feel much difference…

With the tuning slide pulled a certain distance, there's absolutely no difference to what the sound-path "sees" with both ends male, both female, or hermaphroditic (either way, male-female or female-male) tuning slides. When pushed all the way in, there's no change in diameter of the tubing across the butt joint—at either end of the tuning slide (in all of the above cases). When pulled out, there are two corresponding "gaps" between the main tubing and the tuning-slide tubing, thereby causing two small (toroidal) "chambers" with slightly oversized diameters. These two little Helmholtz resonators may (theoretically) affect overtone structure at certain frequencies. Some players (of brass instruments) like to (approximately) fill these gaps by inserting little sleeves that (mostly) fill the gaps, maintaining constant diameter near each joint. For example, for their 1600I "Roger Ingram" trumpet, Jupiter supplies a set of sleeves called "XONS"—XO Nodal Stabilisers—in a few different lengths. [They have little notches on them so that they can be removed with a (supplied) hooked tool.] Some players find they help with reliability of slotting in the upper register.


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[Elow]

What I feel like would benefit an instrument is have the inner tuning slide leg tapered. Having the taper go from the valve through the gooseneck and through the tuning slide leg. Might help with the step? The trombone is not a perfect instrument, think about how much of a gap there is in your slide…

[brassmedic]

What I feel like would benefit an instrument is have the inner tuning slide leg tapered. Having the taper go from the valve through the gooseneck and through the tuning slide leg. Might help with the step? The trombone is not a perfect instrument, think about how much of a gap there is in your slide…

Doesn't Edwards do that? Although I think it's on the bell side. Not sure.

By the way, Couturier did design a trombone with a reversed hand slide. It never caught on.

[modelerdc]

In theory the so called reverse tuning slide is best. However I once took part in double blind tests of two excellent Bach 36 trombones, one had a reverse tuning slide. Listening it was impossible to tell one from another, and in blind playing test the player was unable to tell one from another. In short I don't think this is something the player need worry about.

[Kbiggs]

Most of the time that I’ve seen and heard about, the first leg of the tuning has the male and female tubes switched. On better conversions, the male tube is replaced by a tapered tube that matches the inner diameter of the gooseneck on one end and the tuning slide inner diameter on the other.

Brad, I believe you’re right, if I remember my old Edwards. The bell side of the tuning slide is/was made with a taper. I think at one point it was a machined part, not drawn. But that was ages ago.

[elmsandr]

What I feel like would benefit an instrument is have the inner tuning slide leg tapered. Having the taper go from the valve through the gooseneck and through the tuning slide leg. Might help with the step? The trombone is not a perfect instrument, think about how much of a gap there is in your slide…

Doesn't Edwards do that? Although I think it's on the bell side. Not sure.

By the way, Couturier did design a trombone with a reversed hand slide. It never caught on.

As I recall, both edwards/Getzen inner tuning slide legs are tapered. Much more obvious on the bell side.

I have reversed is a Bach 45… there, the tuning slide crook was quite… weird and made to fit with a weird bore change from the factory. Reversing it maintained the bore progression from neckpipe to the tuning slide crook. Don’t know how much of a difference that made playing wise, but it made my engineer brain feel better.

I also have a reversed 50B tuning slide, but don’t have a horn to ABA compare it with, the tuning slide only fits the Frankenstein horn.

Cheers,
Andy

[tbonesullivan]

As I recall, both edwards/Getzen inner tuning slide legs are tapered. Much more obvious on the bell side.

I'm assuming this is done by varying the wall thickness of the outer tube. That must be an interesting setup used to accomplish that.

[Wilco]

You might need to do something to the bracing when you reverse it. That has an effect for sure

[LeTromboniste]

Then you might as well have a long neckpipe where the bore is tapered all the way to the tuning slide bow, and doing the same with the second leg of the tuning slide, so that with the tuning slide closed, you end up with a continuously conical bell section, and pulling the tuning slide adds only a small amount of cylindrical tubing, without adding gaps. I would think that compared to the huge gaps and changes in bore profile we get as soon as we move our handslide, and the big change in conicity we make by activating the valve, it makes a small difference.

Also, these extra cylindrical sections or sudden expansions in bore are not always detrimental, sometimes it actually makes the horn better, not worse!

[brassmedic]

As I recall, both edwards/Getzen inner tuning slide legs are tapered. Much more obvious on the bell side.

I'm assuming this is done by varying the wall thickness of the outer tube. That must be an interesting setup used to accomplish that.

I would assume it's machined on a lathe.

[tbonesullivan]

I have seen some refer to “reversing a tuning slide”. My understanding is that this means making an existing, normal tuning slide with both inner tube on the tuning slide, to a reversed one with the gooseneck-side leg of the tuning slide being the outer tube.

I was just looking at my 830, and reversing the tuning slide would definitely be a bit more involved, as the bottom braces for both the F and Gb wrap are attached to the outer tuning slide on the lower side. The lower brace for the F attachment in particular is pretty close to the tuning slide, I think you'd need to brace it to something else if you reversed the tuning slide on an 830.

[pfrancis]

I expect it would be simplest to simply brace things on the ferrule. The location of the ferrule would be about an inch or so closer to the valves than those smaller braces currently are. Shires tenors with axials are braced in this fashion, from f att. tubing to main tuning slide ferrule. Worst part would be actually installing so many braces and things in such close proximity.

[sirisobhakya]

I have seen some refer to “reversing a tuning slide”. My understanding is that this means making an existing, normal tuning slide with both inner tube on the tuning slide, to a reversed one with the gooseneck-side leg of the tuning slide being the outer tube.

I was just looking at my 830, and reversing the tuning slide would definitely be a bit more involved, as the bottom braces for both the F and Gb wrap are attached to the outer tuning slide on the lower side. The lower brace for the F attachment in particular is pretty close to the tuning slide, I think you'd need to brace it to something else if you reversed the tuning slide on an 830.

Yes, there would be some fancy bracing involved. However, I am not planning to reverse my tuning slide, at least in the foreseeable future. This topic is from just pure curiosity.

If I have money, first thing I would like to try would be ordering the rotor core of the 835, which should be more open, and swap with current one. But Yamaha doesn’t sell them separately, rather the whole valve (core, casing, and knuckle), which is understandable since they are lapped together. But at around 1100 USD for both valves is a bit too high a cost.

[tbonesullivan]

If I have money, first thing I would like to try would be ordering the rotor core of the 835, which should be more open, and swap with current one. But Yamaha doesn’t sell them separately, rather the whole valve (core, casing, and knuckle), which is understandable since they are lapped together. But at around 1100 USD for both valves is a bit too high a cost.

Did they make any changes to the rotor casing and knuckles? Because all the pictures I see look identical to the bass rotors they have been using for decades now. While they have increased the internal volume by removing part of the core, the actual exit ports and knuckles look to be the same. I kinda question how much of an improvement that can make.

It also might be possible to have an experienced tech modify the cores in your 830 to match the 835 design.

[Matt K]

The reversal can definitely be subtle, though in the 42 that I’ve had it done to, it was an extraordinary difference. I suspect that per usual, my Bach had something funky with it that was ameliorated while I had the procedure done. But I would still do it 10/10 times since it’s a pretty straightforward procedure, even with bracing adjustments.

[sirisobhakya]

Did they make any changes to the rotor casing and knuckles? Because all the pictures I see look identical to the bass rotors they have been using for decades now. While they have increased the internal volume by removing part of the core, the actual exit ports and knuckles look to be the same. I kinda question how much of an improvement that can make.

It also might be possible to have an experienced tech modify the cores in your 830 to match the 835 design.

I don't think they have made any changes, since the tubing parts are all the same and interchangeable.

If I have spare rotor cores on hand I would like to try having a tech modify them as well. But I don't have, and Yamaha only sell as a set also...

[tbonesullivan]

I don't think they have made any changes, since the tubing parts are all the same and interchangeable.

If I have spare rotor cores on hand I would like to try having a tech modify them as well. But I don't have, and Yamaha only sell as a set also...

I think you've probably reached the "if it ain't broke don't fix it" point with the valves. I have never found Yamaha valves to be lacking in throughput when compared to other basses. No, I am not a professional player, but I just don't see them as a major choke point or thing that needs any type of change. They are nice valves. Doug Yeo certainly didn't find any problems with them, as far as I know. I get the whole "well now they have a "better" version of my horn, but I think the "improvements" are somewhat overstated. It reminds me of Yamaha making a big deal when the 830 came out about how the second valve rotated in the same direction as the first valve, and how they went from single piece cork barrels to two piece cork barrels.

Your best bet may be to see if you can get a chance to REALLY compare the new YBL-835 toe to toe with your 830 with the Gold Brass tuning slide. Then It may just be better to see if you can trade up, as it would probably be cheaper in the long run than paying a bunch to have valves modified and /or replaced.

[sirisobhakya]

Your best bet may be to see if you can get a chance to REALLY compare the new YBL-835 toe to toe with your 830 with the Gold Brass tuning slide. Then It may just be better to see if you can trade up, as it would probably be cheaper in the long run than paying a bunch to have valves modified and /or replaced.

Next month I will have a chance. I am going to Japan on holiday, and on the schedule is 5 instrument shops (Yamaha Ginza, Shimokura, DAC, JoyBrass, all in Tokyo, and Miki Gakki in Osaka). I contacted Yamaha and they said there should be all variations of the 835 (excluding the S silver-plated one) in house at the time of my visit. Many other interesting horns as well. Since there have never been and may never will be a chance like this in my home country, I am bringing my horn with me. I shall write a review here after that.

[Sesquitone]

The only (minor) difference between a male and female tuning-slide crook arm is where the (internal) gap appears along the length of the sound-path when the slide is pulled—all other things being equal. To the extent that the resulting small "chamber" might "interfere" with one or more pressure nodes, there could be a slight difference in the energy distribution of some of the higher overtones (where the nodes are closer together), thereby affecting the tone quality or other aspects of tones at particular isolated frequencies. Of course, larger gaps may have "different" effects. As a general rule (unless you are a trumpet player—where the "mouthpiece/receiver gap" is considered to be of particular importance), it's probably a good idea to keep tuning-slide gaps as small as possible. The rough sketch, below (with exaggerated wall thicknesses) tries to portray this. [Taper of the internal diameter plays no role in this effect.]


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[bitbckt]

The adjustable gap receiver on my Adams euphonium has a meaningful effect with every mouthpiece I’ve bothered to try. I’ve felt that settings as wide as 1/4” apart have been appropriate between pieces, though excessive fiddling with it seems to be too much temptation for some and it might be construed a misfeature.

Which is to say the “consideration” of that gap is not exclusive to trumpet players.

[tbonesullivan]

The adjustable gap receiver on my Adams euphonium has a meaningful effect with every mouthpiece I’ve bothered to try. I’ve felt that settings as wide as 1/4” apart have been appropriate between pieces, though excessive fiddling with it seems to be too much temptation for some and it might be construed a misfeature.

Which is to say the “consideration” of that gap is not exclusive to trumpet players.

There are definitely trombone players who utilize teflon tape in order to alter the insertion depth to fine tune the distance between the mouthpiece throat and the leadpipe venturi. There is also the Reeves sleeve system, which does that as well.

[Sesquitone]

Which is to say the “consideration” of that gap is not exclusive to trumpet players.

No doubt other brass-wind players have experimented with "The Gap". But, ever since the Renold Schilke/Vincent Bach "debates" about this (prefer no gap/some gap, respectively), there has been an ongoing obsession with this "question" among trumpet players in particular. The following is borrowed from Bruce Chidester. That (fairly wide) gap looks like a nice little Helmholtz resonator, with a very well-defined (very high) natural frequency. Being very near the upstream end of the sound-path, this has a much greater effect than tuning-slide gaps (or the unavoidable long—and variable—gap within a trombone slide) much further along.


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[elmsandr]

The only (minor) difference between a male and female tuning-slide crook arm is where the (internal) gap appears along the length of the sound-path when the slide is pulled—all other things being equal. To the extent that the resulting small "chamber" might "interfere" with one or more pressure nodes, there could be a slight difference in the energy distribution of some of the higher overtones (where the nodes are closer together), thereby affecting the tone quality or other aspects of tones at particular isolated frequencies. Of course, larger gaps may have "different" effects. As a general rule (unless you are a trumpet player—where the "mouthpiece/receiver gap" is considered to be of particular importance), it's probably a good idea to keep tuning-slide gaps as small as possible. The rough sketch, below (with exaggerated wall thicknesses) tries to portray this. [Taper of the internal diameter plays no role in this effect.]


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Now, to me, the point of reversing an existing design is to remove the gap in the second image. That is, use the fact that you can align the bore exactly to the supposed advantage of the design. One small bore discontinuity instead of a gap between discontinuities.

Note, the only reason I reversed my horns was that it was way faster to reverse two tuning slides with the parts I bought to make them fit the valve sections sitting on the table. Oh well.

Cheers,
Andy

[tbonesullivan]

Now, to me, the point of reversing an existing design is to remove the gap in the second image. That is, use the fact that you can align the bore exactly to the supposed advantage of the design. One small bore discontinuity instead of a gap between discontinuities.

The gap is going to be there whenever the tuning slide is pulled out though. I'm not sure there is any real difference when you have it next to the tuning slide bow as opposed to the goose neck. If the tuning slide is pulled there are always going to be two gaps that the sound has to go through where the bore is slightly wider.

[Sesquitone]

Andy, are you contemplating a simple "overlap" of bore sizes, so that there is always a discontinuity in bore size even when the crook is pushed all the way in? Presumably, for the main bell tuning slide (which is expanding downstream), you'd want the jump to be an increase in bore in the downstream direction on the bell side. That would be a male crook arm. Then why not do that for both arms of the crook? The other crook arm, connected to the gooseneck, would be female. Like a short hermaphroditic hand-slide. There would be no (variable length) "gaps", only two bore discontinuities. Perhaps a sketch would be helpful.

[Doug Elliott]

The gooseneck into a male tube can be a totally smooth transition, and the female tube attached to the tuning slide crook can be a totally smoth transition if the ID is identical to the beginning of that crook. Isn't that the point? There are no actual gaps, only continuous expansion with minimal discontinuity of just the tubing thickness. If the dimensions are reasonable it seems to me that's the best scenario.

[elmsandr]

The gooseneck into a male tube can be a totally smooth transition, and the female tube attached to the tuning slide crook can be a totally smoth transition if the ID is identical to the beginning of that crook. Isn't that the point? There are no actual gaps, only continuous expansion with minimal discontinuity of just the tubing thickness. If the dimensions are reasonable it seems to me that's the best scenario.

This guy gets it.

The gap doesn’t have to exist. If I were designing tooling from scratch, that’s where I’d start.

Might not actually be an improvement, but that’s where I’d start.
Andy

[ithinknot]

Of course, this is why TIB horns died out and we all play TIS.

Everything mentioned above has been done somewhere. This Romeo Adaci (not mine, pic stolen from the internet), for example... neckpipe becomes lower inner TS leg, crook is one piece covering outer leg, tapered bend, and (at least externally cylindrical) upper inner leg.

adaci.jpg

Legs with internal tapers were standard on 1920s TIB Kings. The 3B bell section is basically a cheap-and-cheerful cylindrical rehash of one of those designs. Does the original play better? If you're chasing the TIS feel, yes - there's a smoothness/partial connectivity that you don't get on a 3B - and if you want the focus and response characteristic of the 3B, nah.

[Sesquitone]

On this beautiful RA model (the variable-radius bow curve being reminiscent of the K&H "Slokar"), what stops the travel of the tuning slide as you push it in? Does it just bang up against one of the braces?

[OneTon]

The Bach 42 tuning slide is male on both the bell and neck interface. The interfaces are cylindrical for the length of the mating contact. On the neck pipe side the step off faces the “airstream,” and on the bell side the “airstream” cascades off of the step off. The step off is due to the thickness of the tubing for the tuning slide.

For a Conn 6H, King 2B, Yamaha 697Z, and Schilke trumpets, the male and female fittings respectively are reversed. The “airstream” is always cascading off the step off. Specifically, the tuning slide is female at the neck pipe and male at the bell. There is no gap.

Airstream is used loosely. The Reynolds numbers are low. Any turbulence generated by a back flow step “up” will be short lived, if it were to occur. However, everything makes a difference, though poorly fitting joints and dodgy soldering are likely to cause more noticeable differences than step offs that face the “airstream.” King 2B tuning slides appear to show evidence of applied engineering and instill a pleasing aesthetic.

[Matt K]

Of course, this is why TIB horns died out and we all play TIS.

This is largely the case with Altos. There are downsides to this design that lie outside of the realm of smooth tapers; TIS designs are more expensive, have heavier slides, and can be harder to maintain / keep in parallel. The "middle ground" has essentially won, which is to say a "reversed" tuning slide which is how most manufacturers handle tuning slides these days. It offers a design with fewer gaps than those found on, for example, the 42 without needing to modify the slide. Even Bach has replaced the old design with a "reversed" tuning slide on the A47 models.

[ithinknot]

Of course, this is why TIB horns died out and we all play TIS.

This is largely the case with Altos. There are downsides to this design that lie outside of the realm of smooth tapers

For sure. I'm just making the point that all the options have always been on the table, and there's a lot of "not better, just different" from which to choose... and of course altos have their own very specific real estate problems. For tenors and basses, we're at a point where we could easily have lightweight, reliably parallel CF TIS outers galore. It'll be tried, but I'm willing to bet that it doesn't become the norm.

Even Bach has replaced the old design with a "reversed" tuning slide on the A47 models.

IIRC, these really do just move the bore gap back 3 inches, in that the crook taper starts smaller than the lower inner leg regardless of which side that leg is attached. Somewhere in the archives you can find Benn H discussing all of this WRT "M" neckpipes etc. Maybe it's better, maybe there are some consumer expectations being acknowledged, maybe both.

Interesting that Kühnl & Hoyer have stuck with non-reversed arrangements on all the tenors and basses... they're hardly immune to new design (Slokar/Wogram tapers/bends etc) and would seem to be doing as much BIAS testing as anyone.

[tbonesullivan]

The Bach 42 tuning slide is male on both the bell and neck interface. The interfaces are cylindrical for the length of the mating contact. On the neck pipe side the step off faces the “airstream,” and on the bell side the “airstream” cascades off of the step off. The step off is due to the thickness of the tubing for the tuning slide.

For a Conn 6H, King 2B, Yamaha 697Z, and Schilke trumpets, the male and female fittings respectively are reversed. The “airstream” is always cascading off the step off. Specifically, the tuning slide is female at the neck pipe and male at the bell. There is no gap.

Airstream is used loosely. The Reynolds numbers are low. Any turbulence generated by a back flow step “up” will be short lived, if it were to occur. However, everything makes a difference, though poorly fitting joints and dodgy soldering are likely to cause more noticeable differences than step offs that face the “airstream.” King 2B tuning slides appear to show evidence of applied engineering and instill a pleasing aesthetic.

I prefer the term "vibration flow", as the brass instruments are resonators, not air cannons. You are setting the air column into vibration, and the sound flows through that medium.

I also would really like to see some real numbers on how much of a "step" there is when the tuning slide is closed, assuming that there is a perfect Gapless meeting under the ferrule. I guess the question here is whether the ferrules are tapered or have two sides, so that the thinner gooseneck brass mates well with it when it matches up with the "male" part of the tuning slide. I'm going to need to go home and examine the interior of my trombones tonight to see how much continuity there is.

I also am getting the feeling that a lot of people are ignoring the fact that unless you use a design like the Romeo Adaci trombone, whenever you have the tuning slide pulled out a bit, there is that "gap" that Sesquitone drew a very nice diagram of. The only way to avoid that in a trombone with separate ferrules would be to have the inner diameter of the tuning slide crook match the inner diameter of the outer tuning slide. Do to this it would need to have a portion with a wider inner diameter where it meets the crook. Is that how they are currently made?

[ithinknot]

The only way to avoid that in a trombone with separate ferrules would be to have the inner diameter of the tuning slide crook match the inner diameter of the outer tuning slide. [...] Is that how they are currently made?

Some are, some aren't.

That's the point... the "reversed" arrangement introduces the possibility that a bore gap could be eliminated, but that's not necessarily what happens in every case.

[harrisonreed]

Of course, this is why TIB horns died out and we all play TIS.

This is largely the case with Altos.

Is it? I don't think so. There are two makers that really push TIS altos, and one of them is moving towards TIB.

I have tried both the "main" TIS altos, and not only are they too long with the TIS mechanism pushed all the way in (meaning that TIS is basically is useless unless you tend to play really sharp or like to play short on the slide), they also have slides that are too heavy because of it. It's great that the partials line up perfectly, but playing short on the slide, and with a heavy slide at that, isn't fun. Most altos I see are TIB.

[hyperbolica]

... playing short on the slide...

That's a mischaracterization. The whole reason to have a tuning slide at all is to make use of muscle memory by having a repeatable and reliable position for a reference note. Bb can be put in exactly the same physical location regardless of what group or weather or mouthpiece, or any other variable. Putting Bb as close as possible to the player has the added advantage that you have the best possibility of being able to reach 7th position.

I've been playing TIS for about 10 years on my bass. I see TIB as a compromise. The biggest thing it accomplishes is to make those dents in the tuning slide easier to repair. Most of the metal for a TIS is already there on your TIB slide - just unsolder the oversleeves and you're most of the way there. I don't see the weight as a real issue. And then you can remove some material from the back of the horn and get the bell branch taper back to what it should be for acoustic reasons. Plus the whole reversed, not reversed issue simply disappears. As it's covered by the inner slide most of the time, the issue doesn't reappear in the slide tuning mechanism location.

[harrisonreed]

It's just an opinion, and I was only responding to Matt saying that TIS is really common on alto. I think you don't see TIS on tenor much because it makes the slide too heavy to play fast stuff comfortably. Also, in a pro section the idea that the TIS and TIB will not blend properly, but who knows if that is true. The bass is by itself (in orch, where you're must likely to see a TIS bass), and probably not as worried about playing fast stuff, so TIS is cool.

For alto TIS is attractive because, like you said, lots of players want to tune Eb as close to their face as they can get it. This destroys the intonation with TIB altos. So you can pull the TIS alto out an inch and tune that way and the partials are still great. Again it's just an opinion, but if you care about fine control of the alto slide and the ability to play fast lines on that horn, the TIS is far too heavy.

[hornbuilder]

The gooseneck into a male tube can be a totally smooth transition, and the female tube attached to the tuning slide crook can be a totally smoth transition if the ID is identical to the beginning of that crook. Isn't that the point? There are no actual gaps, only continuous expansion with minimal discontinuity of just the tubing thickness. If the dimensions are reasonable it seems to me that's the best scenario.

Thank you Doug.

[OneTon]

I stand corrected. I took the tuning slides out and looked carefully, with light. There is evidence of joints on both the symmetrical and reverse configurations. They appear to be 0.010 inches or less. “Vibration flow” is okay if that turns your crank. All flows vibrate.

If I blow air through the mouthpiece there is no sound. If I hum into a mouthpiece and horn there isn’t much sound. If if buzz and blow, I produce a tone with dynamics capability. The standing wave of the buzz is modulated, or carried by the air column. If the air column slows down as it transitions step ups or speeds up on step downs, it might alter pitch accordingly. But the trombone isn’t a potatoe launcher and does not achieve Reynolds numbers in a turbulent flow. The Reynolds numbers are so low that there is an annulus of stagnant air next to the tubing. The flow stays in the center and ignores perturbations.

As bad as Bud Herseth wanted to take his Bach Strad with him when he retired from CSO, his personal trumpets were Schilke, and he was perfectly happy with them. Which is to say we’re swatting at spizwinks. We should spend this
time practicing.

[Burgerbob]

I mean, you can say all that... But a reverse tuning slide makes an appreciable difference.

[OneTon]

A lot of people would agree with you. My two favorite horns are King 2B and Duo-Gravis. I am not sure but what something else is going on.

[Doug Elliott]

A lot of aspects of horn design are compensations for other things so it all balances out.
When you reverse an existing tuning slide, it might be better or it might mess up the balance and be worse.

[Matt K]

Well, TIB altos being dead is certainly an exaggeration, but I see a lot of players on them. I guess the Q alto is TIB, but you definitely don’t see nearly as many TIS tenor and basses as you do on alto.

[BGuttman]

Altos are primarily used in orchestra. Most alto parts you get in the modern repertoire are not very technical and the heavier slide of a TIS is not an issue.

Mike Lake, who plays a lot of more modern music (including jazz) tends to play a TIB alto where the slide is lighter and nimbler.

[Sesquitone]

A reverse tuning slide makes an appreciable difference.

Getting back to the original theme of a reverse tuning slide, I'm wondering if we're all talking about the same thing. What I understand about reversing a tuning slide is to convert one arm of a tuning crook from the (more common) male configuration into a female component—with the concomitant conversion of the other component from female to male, of course. On a professional brass instrument, when a male-male crook is pulled away from being flush, there are two "gaps" (of equal length) created along the sound-path, resulting in little oversized "chambers". [Which may or may not cause "problems".] Switching one arm (or both arms) of the crook to female, when pulled an equal distance, will still result in two gaps (of the same size as before)—but they will probably be located in different places along the sound-path.

In the following sketches (where wall thicknesses have been exaggerated for clarity), I've shown, first, a common (but less than satisfactory) habit used on student trumpets and valve trombones (and perhaps other valved-brass), where the tubing of the arms of the crook is simply inserted into the fixed tubing coming from the valve. Which, of course, means that the bore through the crook is significantly smaller than that of the fixed tubing (by twice the wall thickness). In particular, the (unnecessarily) reduced bore of the long third-valve slide would likely cause "problems"!

Then a male-male crook that would be used on professional instruments. Here, the bore of the crook remains the same as that of the fixed tubes. But the crook arms slide into ferrules attached to the fixed arms. Note the two "gaps" when the slide is pulled away from flush.

Next, a female-female crook is shown. In this case, the sliding ferrules are attached to the crook arms. In other words, by definition, the sliding Ferrule is Fixed to the Female component. Note that there are still two gaps (the same size as before), but in different places.

The final sketch shows an hermaphroditic crook—still with two gaps (in different places). This configuration is demonstrated on the first and third (but not the second) valve tubing of a professional trumpet in the last picture.



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[Doug Elliott]

But we're not talking about valve slides here... we're talking about a significantly tapered crook with the possibility of no gaps if you make use of the straight tubing as part of the overall expansion.

[Sesquitone]

But we're not talking about valve slides here... we're talking about a significantly tapered crook with the possibility of no gaps if you make use of the straight tubing as part of the overall expansion.

Yes, I'm aware of that. I'm just using valve slides as examples of male and female coupling.

Perhaps I'm missing some important point. If there are no gaps when the bell bow is pushed all the way in (male/male, female/female, or hermaphrodite), so that the two arms (of different bore size) are flush up against the corresponding tubing of the gooseneck and bell—and if there are no discontinuities in the sound-path in that configuration—when you pull out by any amount, there must be two gaps created, no matter which combination of male/female, &c., is being used.