Inversed/Reversed Tuning Slides

[Dan Schultz]

Hey bloke... Hey Rick... I'm confused! Different manufacturers throw these terms around and never give a good explanation. Are 'inversed' and 'reversed' the same thing? Do any tuba manufacturers offer anything other that conventional slides?

BTW... if there are any trumpet guys on the board, I had a good look at the new Severinson Trumpet last Saturday and it has conventional tuning slides! ... I mean slides built just like the student Bundy and Bach trumpets.

[Rick Denney]

Hey bloke... Hey Rick... I'm confused! Different manufacturers throw these terms around and never give a good explanation. Are 'inversed' and 'reversed' the same thing? Do any tuba manufacturers offer anything other that conventional slides?

Some main tuning slides have a dual bore and only fit one way, if that's what you mean. And many have a water keys that dictate how they go. My Yamaha 621 has a dual bore tuning slide, but the slide on the Miraphone can go in either way. Some slides also have offset ferrules and can only go in one way. The upper fourth slide on the Holton is that way. And some slides have chamfered inside edges on the leading edge of the slide, and should only be installed so that the air flows into the chamfered end and not out of it. That's a favorite trick of Matt Walters to help balance the response of different valve branches a little bit.

I've always thought that "invert" means you take something and turn it upside down, while "reverse" means you turn it back to front. So, I might pull a slide and invert it to drain the water, and reinstall it in the reversed position by mistake.

Rick "not sure if he answered the question" Denney

[Dan Schultz]

Hey bloke... Hey Rick... I'm confused!

Some main tuning slides have a dual bore and only fit one way, if that's what you mean.

Well... kinda. The 'dual bore' could mean the main tuning slide on a Conn 14i baritone. What I'm talking about is the configuration where the smaller tube goes inside the larger in the direction of the sound path. The result is a tuning slide with an 'inner' tube and an 'outer' tube. What's that called?

[Tom]

I've heard of them called "reverse flow tuning slides," which (like the other terms) is not totally accurate...afterall, the flow itself isn't really reversed.

The Meinl Weston 2000 has a lower 3rd valve slide with this design. I could get you a picture if you're dying to see one.

[Rick Denney]

Well... kinda. The 'dual bore' could mean the main tuning slide on a Conn 14i baritone. What I'm talking about is the configuration where the smaller tube goes inside the larger in the direction of the sound path. The result is a tuning slide with an 'inner' tube and an 'outer' tube. What's that called?

Oh, I get what you mean. The upstream slide is male on the instrument and female on the slide, while the downstream slide is male on the slide and female on the instrument. That way, the air flow never faces into the edge of the slide tube.

I don't think either "inverted" or "reversed" describes such a slide. "Directional" would be my choice. I've never seen one on a tuba, but someone else said the 2000 has one. I can hear the ad copy now..."The open-blowing directional-flow tuning slide on the Rick-o-phone means will make you sound like Arnold Jacobs even though you play like Rick Denney."

Rick "who doesn't know of a standard term for that" Denney

[Art Hovey]

I think what you are describing is like the main tuning slide on most tenor trombones, except Bach. The idea is for the air to encounter a small increase in bore as it enters the first part of the slide and another small increase as it leaves. This is good because it approximates what the air would encounter in a continuously tapered tube. (In a conventional tuning slide the air encounters a decrease in bore size as it enters the first piece of slide tubing.) It seems like a good idea, and I have incorporated it into three of my own project horns. But it does make the bracing less solid. Also, Bach trombones seem to do very well making their slides the old-fashioned way.

[roweenie]

Reviving this thread.....sort of

Question: are there any advantages to having a main tuning slide where the small side (going into the bottom of the 4th valve) is reversed, meaning the outer tube is part of the crook, and the inner slide is attached permanently to the valve set?

There are some who believe that this location is an area where some "mischief" can occur, and that the fixed inner slide (providing a consistent bore size, regardless of the position of the MTS) can improve some of this.

Any empirical evidence (not necessarily opinions, although that would be interesting, too) would be greatly appreciated....

[windshieldbug]

Question: are there any advantages to having a main tuning slide where the small side (going into the bottom of the 4th valve) is reversed, meaning the outer tube is part of the crook, and the inner slide is attached permanently to the valve set

Since you've already put the tuning slide past the valves, any gap in the slide due to position is not moved very far. Surely the disruption on airflow and/or wave generation of even an open valve (piston OR rotary) would have more effect on playing, yet we still do...

[windshieldbug]

Question: are there any advantages to having a main tuning slide where the small side (going into the bottom of the 4th valve) is reversed, meaning the outer tube is part of the crook, and the inner slide is attached permanently to the valve set

Since you've already put the tuning slide past the valves, any gap in the slide due to position is not moved very far. Surely the disruption on airflow and/or wave generation of even an open valve (piston OR rotary) would have more effect on playing, yet we still do...

[roweenie]

Yes, all that is true, but theoretically, there is something specific about this particular spot (exiting the 4th valve into the MTS) where a gap in the bore can make for trouble.

I've got a horn where I need to change the length of the MTS, so I'm debating the pros and cons of doing this before I tear into it....

[pjv]

You could write to Miraphone and ask them what they think. They applied this to their 1291. I'd think they'd have a reason for this.

[Dan Schultz]

You could write to Miraphone and ask them what they think. They applied this to their 1291. I'd think they'd have a reason for this.

Yes, they did. And it left one side of the tubing poorly braced. That's my only complaint about reversed slides.

[roweenie]

I agree, Dan - unfortunately, I think that since the fixed tube is an inner slide, inadequate bracing is unavoidable.

Actually, it's for this very reason that I'm hesitant to modify it this way. If there is no perceptible difference, why bother?

[oedipoes]

The Norwegian Star has the reversed tuning slide setup as well.

Don't know if it makes any difference, can't compare, it came like that ...
You could ask Baadsvik, probably they tested difference versions during the development at Miraphone ...

[pjv]

So again we arrive at Miraphone. A company with big reputation made this decision. You could ask them why and you might get an answer you can use.
For the record: I own a 1291. I wasn't looking to buy a 1291 but it was dirt cheep and in great condition (outside of some dents). The tuning slide was perfectly aligned (even though the previous owner had never brought it to a repairman) and I cn't say I feel the tuning slide is unaptly braced. I am also not a repairman.
On the other hand I'm also not a high school student who vents his frustrations out on the tuba so I'm not expecting any problems (even though I almost exclusively transport my tubas in gig bags).
Good luck.

[gwwilk]

My Miraphone 191 has a half-reversed tuning slide with a male tube extending from the fourth valve and a male tube extending from the slide into the remainder of the bugle. When oiling the rotors with the tuba on its bell this prevents slide grease from being dissolved and carried into the rotary valves. Oiling the rotors is a straight shot from the tuning slide whereas using the leadpipe would tend to carry unwanted debris from there down into the valves. My Rudolf-Meinl Bayreuth has a removable leadpipe which makes oiling the rotors from the top incredibly easy.

[roweenie]

Well, I decided to take the plunge and change the MTS on this E flat tuba to a reverse one:





And, while I was at it, I also made the 5th valve removable (it was in a difficult spot for servicing):



The verdict is that I do perceive a slight difference in low note response, especially below the low B flat. So, there may be actually something to it (YMMV)....

[PaulMaybery]

Love the creative engineering.