Re: Damping


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Posted by Rick Denney on July 18, 2001 at 11:39:18:

In Reply to: Damping posted by Philip Moore on July 18, 2001 at 10:52:26:

I have wondered at the same thing. That resonance sounds wonderful up close, but I wonder if it absorbs some of the energy of the vibrating air, and robs the sound of some of its core out front. I know that some folks use a leather belt or a plastic bell rim on the bell to damp vibration, reporting a darker, more focused sound out front.

I suspect it has to do with how the horn feels to the player, versus how it sounds to the audience. The lifted leadpipe is, I suspect, in the former category, but I'm sure that many who have paid to have it done will dispute that supposition.

Monsterweights don't damp vibration in the sense of absorbing it through plastic deformation (as would a leather belt). They add weight to the system, the same as the interchangeable bell attachment ring on my York Master. That extra weight lowers the resonant frequency, and increases the energy required to achieve a certain degree of vibrational movement. That has a similar effect to damping in many cases, it would seem to me. But once set to vibrating, a horn with Monsterweights will vibrate longer because the weights have done nothing to minimize the elasticity of the metal and vibrate with greater momentum. So, it takes more energy to get them going, but once going, they probably degrade the sound more. If they are heavy enough, it may be that the energy required to get them going to a significant degree is just too much to bother about.

It may also be that vibration in the valve-body portion of the instrument has more negative effects than in the bell. Of course, it could also go the other way.

The bell on the York, despite that heavy ring, does ring sympathetically a bit with some notes when I play, which I perceive as "resonance". One of these days, I'll put something on it to damp it out see if any difference can be measured. I can feel the vibation with my hand, and with my hand damping the sound, it makes a noticeable different up close. But I don't know how that affects the sound out front.

One key difference between the way the York and Yamaha 621F tubas sound to me is that resonance. When I hold my hand on the York's bell, the sound loses some of that resonance and sounds more present (which some might call "dead"), just as the Yamaha sounds to the player.

We interpret so much of what we think about horns from what we can hear as players, and I'm believing more and more that what we hear has not so much to do with what the audience hears, unless we have carefully calibrated our hearing with the hall in mind. I know that the sound of the York impresses me most when I'm in a live hall, and can hear the sound coming back to me. Therefore, I'm thinking I will not use the York in our next outdoor concert as I did last night. I think I'll take the Miraphone, where that extra focus might be helpful.

Rick "who was most impressed by the Monsterweights testimonials of external listeners" Denney


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