Re: Metallurgy

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Posted by Rick Denney on January 30, 2001 at 18:40:37:

In Reply to: Metallurgy posted by Steve Dedman on January 30, 2001 at 18:07:44:

I have an engineer's understanding of metallurgy, which means I know just enough to get myself in real trouble. Of course, I've never let ignorance of topic slow me down before.

I have to say that I'm dubious of the effects of the copper content on the playing qualities of the horn. The York that I played last Saturday had a profound impact on my thinking about such instruments, and the quality that impressed me was apparent in three notes. This was not a subtle effect explainable by a slight difference in alloy.

And I suspect that the properties that matter are quite similar between the different alloys. What properties matter? I would think the modulus of elasticity, which describes how the metal moves in relation to the stress that is put on it, is the only really important parameter in terms of the primary effect on sound. Others would be different, too, such as yield strength, malleability, ductility, toughness, and so on, but those would matter more to the manufacturer than they would to the player. Sure, a higher copper content might reduce the strength of the alloy, but I doubt that it would significant affect its elasticity. If strength were a primary issue in actual playing, then the horn would quickly fall apart.

But that's not to say that the material choice doesn't have a secondary effect. For example, if the brass in old Yorks was not as strong, then they may have used thicker material to compensate for that fact. It has been postulated before that old American instruments used brass with a coarser grain than German instruments, which might also encourage makers to use thicker material. But the CSO York is not that thick, judging from its surprisingly light weight, which is no surprise given the amount of buffing that has been done to that horn. The York that I played Saturday was not as heavy as my York Master, which is a much smaller instrument. Another possible secondary effect has to do with the malleability, which would change the workability of the material between annealings. This *could* result in a horn that has lower residual stress, though I have to say that I'm dubious about the effects of some residual stress, too.

I'm reasonably sure that the instrument I played on Saturday played as well as it did because of its shape, not because of its material. In fact, many of the copies play superbly, to hear players describe them. Given the subjective differences in how players respond to different horns, it is possible that we have achieved copies that are as good as the original. I don't believe anyone has done a side-by-side test, except Gene Pokorny with his Yorkbrunner (which may or may not be the best copy available for him to try). The only other faithful copy (excepting the Yamaha) is the Nirschl, whose owners compare those horns favorably to the original.

Rick "waiting to be corrected" Denney

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