Martin Eb 17" bell high pitch

[Dan Schultz]

Wow! That's easily a difference (total) of over 4". I'll bet one could just take off the larger bow and do a little retapering (if that's even necessary) and get the pitch up to where you want it.

However... there appears to be other differences, too. At a quick glance, it looks like the tuning circuits are the same. But... upon closer inspection... it looks like the valve section on the low-pitch horn is located up a bit, too. I think the tuning circuits are going to have to be cut, too.

[opus37]

My Matrin has both the low and high pitch to it. There is a removable extended on the main toning slide (about 7 inches long) that can be in place or not. Mine tones to 440 with the low pitch extender all the way in. With it out, I can't get flat enough.

[opus37]

OK I did some real measurements. The extender on my horn is 4 inches. The tunable tubing on the high pitch is 3.25". That isn't enough to get it in tune so mine needs 0.75" to get to 440 from 430. Mine is the larger version of the Eb and has 3 valves (manufactured about 1912) so your may be different.

[Dan Schultz]

.... About how much would an Eb horn need to be shortend to go up 10 cents? ....

A quick test would be to see how far you have to pull out to go down 10 cents. That would be about the amount you would have to take out to go up 10 cents.

[opus37]

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It has a 20" bell.

[imperialbari]

With extenders it always is extremely important to make clear whether you give the measurement of the pull of one branch or the measurement of the combined pull of both branches.

Klaus

[opus37]

Since I only pull one the main slide and not the extended, my measurements are the combined pull.

[imperialbari]

I hadn’t thought of the extender, so there you got me. Still we need to talk in a very specific way on TubeNet, as some are trained in measurement theory and some are not.

In a way this one is simple: if you pull a tuning slide 1" the effective acoustic pull is 2". Why? Because virtually all low brass tuning slides consist of two branches connected by a U-shaped crook. Some of the smaller brasses have a tuning leadpipe, which is a single branch.

Seen in this light, is you pull the 0.75" or 1.5"?

Klaus

[opus37]

Since the requester was asking linear dimensions that's what I gave him. Thus, the 0.75" is linear and acoustically, is is 1.5".

[imperialbari]

Thank you! I think in both dimensions, so I simply need to know in what context a number has been achieved.

Klaus

[opus37]

No problem. The issue is similar to discussing the deer you just shot. You might say it's a 10 point buck. In Minnesota, you count the points on both horns. In Colorado, you count just one side. So a 10 point buck in MInnesota is a 5 point buck in Colorado. Big difference!! Location and local custom are important considerations. It's usually best to state specifically what you mean so there is no misunderstanding. Thanks for helping keep this information understandable.