Dual-bore slide in single-bore horn bell? + Rotor with weird bore size

[sirisobhakya]

What would it be the effect of using a dual bore slide with the lower leg larger than stock horn? Say, putting .562”-.578” into a .562” horn? Since the valve tubing is designed and optimized for .562” lower slide bore, would using the .578” slide throw it off-balance?

Another question: where could I find a rotor with non-standard bore, for example 13.00mm?

[hyperbolica]

An 88h is made so it can accept a 525, 547 or 562 lower slide. I've tried them all, and they work pretty well. Never tried a 578. The valve on most horns is at least one size up from the stated bore of the instrument. Bell sections start the conical part of the horn. A King Duo Gravis is 562 through the valve section, so it wouldn't make sense to put a big slide on that. It might work, but it might not give you a great sound. Most modern basses are bigger through the valves, and some bigger through the 2nd valve.

The outer slide is larger than the inner slide, so the bore goes up and then back down, so this bore restriction happens in all trombones, although I'm not sure it's a design goal, or something you should aspire to. Try it. If it does what you want, cool, if not, you learned something. I wouldn't spend any money to modify a horn to do it, if that's what you're asking.

[Burgerbob]

Works fine on bass trombones, at least on Bachs.

[elmsandr]

I would object to saying that anything has really been "optimized." I am not sure if there has been much engineering. There has been some drafting, and sure they are generally sized, but I do not know if there is a theoretical or mathematical basis for selecting the size that is on any given design.

The "design" of the Bach 36/42 works with both a .525 and a 547 slide by design and rather famously works pretty well with a .562, so why would the rotor care too much if any of these three sizes were mixed? The soft machine (the player) will probably care more than any of the brass.

Cheers,
Andy

[tbonesullivan]

The only issue you might have is that the tenon wouldn't be the same size, and it wouldn't fit. That's the only thing that really keeps one from grabbing an out of the box Bach 36 slide and throwing it on a 42, or a Bach 50 slide on a 42, I think anyway. The nuts are the same, and the external receiver is the same, but it's machined out a lot more on the larger horns.

[Matt K]

Usually the bore size of the tubing is at least as large as the lower leg of the slide. Bass trombones have between .57x and .593 with the latter being probably the most ubiquitous at the moment on everything except the Jupiter horns (which actually share the valves with tenors despite not being the normal tenor bore of .562 for valve tubing). So even if an inversion caused an issue, it wouldn't actually cause such an inversion on most horns.

[Ndwood]

Also keep in mind that the valve tubing bore on any horn will most likely be less than the bore of the outer slide and slide crook. It’s best not to over-think these things...

[whitbey]

It all works. Some setups are useful and others while they work would never be used.

Because I have a valve on my jazz horn it has the same tenon that the Bach bass and Edwards have. So I can put a large slide on the small horn and the other way around.

The big bass slide on the small horn and vice versa work, but you have to blow to keep the sound good. The 547 slide on the small horn work good enough to use if a slide was damaged. My 525/547 slide works pretty good on the jazz horn.

The small 500/508 slide on the 547 Edwards plays like some German horns. Maybe a little better.

Pretty much any slide on the 547 works. Just a different blow.

The 562 on the 547 horn works just fine. My 547/562 works fine on the bass.

While all this works, the normal sizes work so good that these trials do not last very long.

[dukesboneman]

Check out a Conn 32H (if you can find one)
.500/.522 Great horns

[Trav1s]

Check out a Conn 32H (if you can find one)
.500/.522 Great horns

Yes indeed.

[Mv2541]

What would it be the effect of using a dual bore slide with the lower leg larger than stock horn? Say, putting .562”-.578” into a .562” horn? Since the valve tubing is designed and optimized for .562” lower slide bore, would using the .578” slide throw it off-balance?

Another question: where could I find a rotor with non-standard bore, for example 13.00mm?

In terms of bass bones, I believe for the major modular makers (Shires/Edwards/Rath) you can use either a single or dual bore on any bell section.