French horn rotor for alto?

[Elow]

Not that i own or play alto, but would a french horn rotor be the right size for alto?

[BGuttman]

Way too small.

The Conn 36H uses a similar valve to the 79h tenor.

Plus, a double French Horn uses a double valve.

[harrisonreed]

I just checked the parts site for Conn, and the valve for the 36H is unique to that instrument. I think a horn valve would be too small.

[Finetales]

It would have to be a pretty small alto. Modern horns have a .468" bore...I could see a horn rotor working on a soprano trombone maybe.

[Crazy4Tbone86]

I don't think it is a good plan at all. As Finetales stated, the most common bore size on a horn is .462. Most alto trombones (even the smaller ones) in the neckpipe area are .495 and larger.

[Elow]

Isnt the bore larger at the rotors?

[BGuttman]

Isnt the bore larger at the rotors?

You work in a shop. Find a single horn and measure the OD of the tubing going in. Then measure the OD of a medium bore trombone with F. You should have your answer.

[Thrawn22]

Isnt the bore larger at the rotors?

Not always.

In the end a f horns rotors would be way too small. I would say a king 3B rotor would be a good candidate to use on most Altos.

And by 3B, i mean .508 3B. Though, a 3B+ rotor would be better.

[Crazy4Tbone86]

Designs vary on trombones. The most popular design is for the rotor tubing is to step up 15 to 30 thousandths of an inch from the lower slide exit diameter. However, some models keep the rotor bore the same or close to the the lower slide diameter.

Making the tubing "oversized" in the rotor section was attempted with a few models back in the late 1990s and early 2000s. It wasn't too successful. I have an Allora .547 bore horn (made by B & S in Markneukirken, Germany and distributed by Woodwind/Brasswind) that I bought in 2002 on a whim. The rotor section had some tubing that was .593, yet it came back down to .562 at the beginning of the gooseneck. It always played a little strange. When I modified the horn to have all .562 tubing in the rotor section, it played considerably better.

Alto trombones are unique beasts. If you allow the bore to grow too rapidly in the bell section, all sorts of intonation problems will result......especially the 6th partial B-flat. If you fabricate an alto with a rotor, my recommendation would be to keep the rotor section very close or only slightly larger than the exit diameter of the lower slide.

[Elow]

Isnt the bore larger at the rotors?

You work in a shop. Find a single horn and measure the OD of the tubing going in. Then measure the OD of a medium bore trombone with F. You should have your answer.

I’ve asked the guys if we had a way to measure bore and he said no.

[BGuttman]

You work in a shop. Find a single horn and measure the OD of the tubing going in. Then measure the OD of a medium bore trombone with F. You should have your answer.

I’ve asked the guys if we had a way to measure bore and he said no.

I'm not suggesting you measure the bore. Get a caliper and measure the outside of the tube. The tube thickness for the two valves should be pretty consistent. At least consistent enough to answer your question.

[Crazy4Tbone86]

Good call Thrawn22! When I was in Markneukirken in 1999, I bought a Pfretzschner alto bell. It was a great deal.....he sold me the bell for $100....I couldn't afford a complete alto trombone which was $4000. Anyway, when I started building a horn around the bell and selected a rotor to use for a B-flat attachment, I chose an old 3B rotor. I can't remember the exact bore size of that rotor section, but I think it was about .529 or .530. Considering I constructed a lower slide for that alto from .525 Bach 36 parts, I thought the 3B rotor was a great choice and it has worked well on this particular alto.

Before any of you out there say...."A .525 bore on an alto. Are you crazy?" You must keep in mind that there are a few German alto trombone makers that offer larger bore altos. Pfretzschner is one of them, and his horns are outstanding. I think one of his best models is a dual bore that is something like .525-.547.

[Crazy4Tbone86]

I'm sorry Elow. If you and your co-workers cannot measure the bore of an instrument, it doesn't speak well for the credentials of your shop. Measuring things accurately is an essential skill needed to do work on all wind instruments. If your "shop" doesn't have measuring equipment, you should certainly invest in your own set of tools. In my opinion, this is something that you should probably address before diving into more modification ideas or posts.

There are two or three ways you can accurately measure the bore of a brass instrument:

1. Use a quality caliper/micrometer that is accurate to .001 inch or better. The cheaper ones are not as accurate...you get what you pay for.
https://www.amazon.com/digital-calipers ... 2476630011

2. Use a quality micrometer and an inside diameter spring caliper. A micrometer is a great tool for measuring dent balls and sheet metal thickness.
https://www.amazon.com/s?k=micrometer&r ... nb_sb_noss
https://www.amazon.com/Big-Horn-19053C- ... ial&sr=1-5

3. Use a quality micrometer and dent balls (you can at least get an accuracy within 2 or 3 thousandths).

I am a teacher at heart and I aim to help those who seek knowledge. I think you have an enthusiasm for our instrument and some ideas that could result in great instruments. However, I think you need some tools to help you calculate some things before you throw ideas out to the general public. Please consider my advice and think about the wisdom you could gain from these tools.

[Finetales]

Before any of you out there say...."A .525 bore on an alto. Are you crazy?" You must keep in mind that there are a few German alto trombone makers that offer larger bore altos. Pfretzschner is one of them, and his horns are outstanding. I think one of his best models is a dual bore that is something like .525-.547.

At the risk of getting more off-topic, the best alto trombone I've ever played was a prototype B&S single bore .547" alto trombone (with a valve).

[Thrawn22]

Good call Thrawn22!

I have a good idea every now and then

[Crazy4Tbone86]

Finetales....did you buy that B & S alto, or is this another "the one that got away" stories?

[Finetales]

Finetales....did you buy that B & S alto, or is this another "the one that got away" stories?

It wasn't for sale, unfortunately...one of my professors in undergrad helped B&S design the instrument. He had (and still has) the prototype and then later a pre-production model. Both were amazing. Unfortunately I don't think the instrument ever saw production, and multiple attempts to contact B&S about the instrument didn't work. I still want one!

[timothy42b]

Finetales....did you buy that B & S alto, or is this another "the one that got away" stories?

It wasn't for sale, unfortunately...one of my professors in undergrad helped B&S design the instrument. He had (and still has) the prototype and then later a pre-production model. Both were amazing. Unfortunately I don't think the instrument ever saw production, and multiple attempts to contact B&S about the instrument didn't work. I still want one!

Out of curiosity, what is the advantage of a large bore alto?

[Crazy4Tbone86]

For me, the advantage of a larger bore alto is that it blows freely like a .547 tenor. I find that most altos have a tremendous amount of back pressure (resistance). My problem is finding balance in an alto....if the bore is larger and it is free-blowing, the upper register loses clarity. If the bore is smaller and the upper register has clarity, I must deal with all of the back pressure.

Of course, I'm simply looking for a perfect alto trombone that does not exist. I am well aware that I just need to settle on a horn and consistent practice is the real solution.

[timothy42b]

My problem is finding balance in an alto....if the bore is larger and it is free-blowing, the upper register loses clarity. If the bore is smaller and the upper register has clarity, I must deal with all of the back pressure.

Doesn't that imply that if the bore is large, we play too loud?

An alto is easier to play in the high register because we play more moderately, right?

[Finetales]

Out of curiosity, what is the advantage of a large bore alto?

This alto in particular was designed to be a perfect sonic match to a modern orchestral section with a .547" tenor on 2nd and a .562" bass. And let me tell you, they succeeded in SPADES with that goal. My professor did a masterclass on the instrument where he performed excerpts from Brahms symphonies with a section and it was an incredible sound. Blended perfectly with the modern tenor and bass, both in tone and volume, but still sounded distinctly like an alto trombone and not just a smaller tenor. I wish he had had that masterclass professionally recorded because if that was on the Internet every principal trombonist would want one. It's such a shame the instrument seems to be vaporware now because it really could have made a big impact.

[Crazy4Tbone86]

To timothy42....

I don't think this is a volume thing. The smaller bores make me play LOUDER than I want to play because I am struggling with the imbalance of resistance. When playing alto, I need to use more air support to keep the sound alive and the result is less finesse.

When I play on my favorite .547 bore horns, I am completely relaxed and at ease over the entire range of the instrument. This is because I have found the perfect resistance level. I have yet to find that comfort with my alto trombones. I am getting closer, but the relaxation level is definitely not there. When I built some larger bore altos, I got the resistance level right, but the intonation problems were horrible (please see the alto trombone thread under the "instrument" category).

To emphasize my point.....this past weekend I was practicing the Creston Fantasy on both .547 bore tenor and alto. I am fluent on the alto, so slide positions and music reading are not an issue. I find this piece and any piece with a high tessatura much, much easier to play on the tenor because the resistance is not quite right on the alto. In theory, it should be the opposite.....the piece should be easier to play on alto.

My purchase of some Doug Elliott mouthpieces has helped tremendously on alto, but the resistance issue is still lingering. I think this is a thing that is very personal for certain players. I know some very "natural players" that are not impacted by resistance....no matter what horn they pick up, they sound great. I am greatly impacted by resistance. If the resistance is correct, I can play with the best of musicians. If the resistance is wrong, I sound like a struggling middle school student.

[harrisonreed]

Resistance? What resistance?
It actually does work though... Makes it feel like tenor.

101966658_10159701707529638_2880951632797892608_o_1.jpg

These are just my own thoughts, and I'm not saying that I'm right, because I know nothing about physics, but for the sake of discussion, I will say that I think most brass pedagogy has got it wrong when it comes to resistance. The longer the pipe, the more resistance it has. There is so much more air added when you make a pipe longer, vs changing the bore size. In my experience, alto trombones have LESS actual resistance than a tenor trombone, because the pipe is shorter, but the bore size is often essentially the same as, say, a 2B. There is less air that you need to get vibrating, and it pushes back on you less. We perceive this as being very different from the way a tenor trombone feels when we play it. Because it is.

So there's two ways to "fix" it without changing gear, initially. One is to increase the speed and volume of our air through the mouthpiece. This is mentioned above, "I have to play a lot louder". This will cause the air air in the pipe that we are vibrating to push back on us a bit more, and it feels like our tenor trombone. The other way to "fix" it is to increase the resistance on our end of the mouthpiece. Tension in the embouchure, chest, throat, etc. This will also influence the resistance in the whole system and get the air vibrating, but in an unnatural way. And it's easy to think, "wow, this horn has so much more resistance on it", when it's really artificial resistance that we created in our own body. The resistance has to come from somewhere to get the air in the pipe vibrating.

So, we can turn to equipment as well, to facilitate the creation of resistance in the first way mentioned above, resistance of how the air pushes back on us blowing naturally. One way is to increase the bore size over the length of the pipe. More volume of air means more air needed to be moved to get it vibrating, but at a SLOWER speed. It only feels like less resistance because of the speed of flow -- there is more air now that you need to apply energy to. Another way is to increase the volume of the leadpipe, again increasing volume of air but potentially decreasing the speed of the flow. Another way is to DECREASE the size if the leadpipe venturi. The venturi effect forces air to speed up as it is pushed through the choke, so that this faster air is met with resistance by the rest of what needs to be moved in the pipe. This changes that way the player has to blow, but in the end can have the same result as a larger leadpipe. It all depends on the individual. We can also achieve this resistance balance with changes to the mouthpiece. Adding weight to rotor caps, the mouthpiece, the bell material, etc, also effects overall resistance and how the energy is transferred to the vibrating air across the entire instrument. Finally, and the point of the tongue in cheek image used above, preventing areas of the instrument from vibrating freely also changes the way energy is transferred to the air in the pipe. Wrapping that portion of the bell increases the resistance of the instrument, which means that it takes less energy from us to get it to push back and speak. So it feels more open (because we don't need tension on our end)....!?!

Compound it all with the fact that a small room makes us increase tension inside to create resistance, while a large hall seems to let us play effortlessly without any tension at all. But the room couldn't possibly make any difference to our actual perception of resistance while playing....right....??

[8parktoollover]

For me, the advantage of a larger bore alto is that it blows freely like a .547 tenor. I find that most altos have a tremendous amount of back pressure (resistance). My problem is finding balance in an alto....if the bore is larger and it is free-blowing, the upper register loses clarity. If the bore is smaller and the upper register has clarity, I must deal with all of the back pressure.

Of course, I'm simply looking for a perfect alto trombone that does not exist. I am well aware that I just need to settle on a horn and consistent practice is the real solution.

but then wouldn't the bore size be disproportionate to the tubing length?

[Crazy4Tbone86]

Harrisonreed,

Thank you for your interpretation of a problem that I (and many) may never solve about the alto trombone. I will continue to practice regularly on the alto trombone and remain optimistic!

Your first two paragraphs have grabbed my attention the most. Essentially, the perceived resistance may be very different than the actual resistance.....that alone gives me much to ponder. I find that there are so many psychological things about alto trombone and I know those must be sorted through before mastery can be attained.

I feel like we have wondered far from the original post on this thread. Possibly, it would be best to discuss alto trombone in the "equipment" or "teaching and learning" categories?

[timothy42b]

I don't claim to know but I don't think the resistance we feel is resistance to air flowing down a tube. I think it is resistance to sound wave. Those two are not necessarily related.

[harrisonreed]

I don't claim to know but I don't think the resistance we feel is resistance to air flowing down a tube. I think it is resistance to sound wave. Those two are not necessarily related.

Right, sound wave or getting the air vibrating. I don't know what that's called. That's why a mouthpiece has almost NO resistance -- because it is so short. The speed and volume of air needed to get a pressure wave started in that would be a lot more than I have in my lungs. That's why the buzzing that we do on a mouthpiece has no harmonic series -- it is 100% resistance buzzing caused from our face and body.

[timothy42b]

I don't claim to know but I don't think the resistance we feel is resistance to air flowing down a tube. I think it is resistance to sound wave. Those two are not necessarily related.

Right, sound wave or getting the air vibrating. I don't know what that's called. That's why a mouthpiece has almost NO resistance -- because it is so short. The speed and volume of air needed to get a pressure wave started in that would be a lot more than I have in my lungs. That's why the buzzing that we do on a mouthpiece has no harmonic series -- it is 100% resistance buzzing caused from our face and body.

Years ago I did a quick and dirty measurement of the pressure drop through the horn, with an improvised manometer. I used a water filled length of aquarium tubing and a plumbing tee-fitting between mouthpiece and trombone. I really should repeat that trying for more accuracy.

But the results were this: pressure drop from mouth to ambient, 13 inches water. Pressure drop from mouth to end of mouthpiece while playing, 12 inches. So the resistance from lips and mouthpiece was 12/13 of the resistance of the total horn, on that day anyway. Of course that is resistance to air flow, not vibration or sound wave.