Strange bell vibrations on specific tone

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Nomsis
Posts: 149
Joined: Feb 02, 2022

by Nomsis »

When I play a c :bassclef: :line6: my silver hüttl trombone (which went trough a massive undenting process after I bought it for very little money) sucks all my energy and puts it in bell vibrations one can feel and hear clearly when playing it. This behavior happens just in a very specific frequency spot on a well tuned c. This is just like when one sings in resonance with a good wine glass. It is a little annoying because it makes this tone very unresponsive. Since I use this instrument just for marching purposes I could live with it but I would rather not. So if you have some low effort tip to stop the universe sucking my energy on c please give it to me - thanks (:

I tried damping it with a tshirt wrapped around the bell and this works but I feel like this looks uncool and makes the trombone even more front heavy than it is already.
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Doug_Elliott
Posts: 4155
Joined: Mar 22, 2018

by Doug_Elliott »

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harrisonreed
Posts: 6479
Joined: Aug 17, 2018

by harrisonreed »

<ATTACHMENT filename="Screenshot_20191219-171055.png" index="0">[attachment=0]Screenshot_20191219-171055.png</ATTACHMENT>
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bassbone1993
Posts: 435
Joined: Feb 10, 2023

by bassbone1993 »

[quote="harrisonreed"]Screenshot_20191219-171055.png[/quote]

I wish they still made this, as I have very little skill to make this
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ghmerrill
Posts: 2193
Joined: Apr 02, 2018

by ghmerrill »

As a quick trial, you might try "vet wrap", though it's now not popular to refer to it as that and you might have to look for "self-adhesive bandage" or "self-adherent wrap" or some such. That would at least show you what the effect of a similar sort of "dampener" would have, and you could either stick with it ( :lol: ) or try something else. There are various sorts of (smooth flexible plastic) shelf/drawer liners out of which it would be pretty easy to make something (even with using some self-adhesive Velcro strips on the wrap so you could put it on and take it off). The major drug stores carry the self-adhesive bandage or you can get it from Amazon.
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Nomsis
Posts: 149
Joined: Feb 02, 2022

by Nomsis »

Thanks for your interesting suggestions. The tone halo looks like a very interesting toy to play around. Where could I buy this (I'm located in Germany) and what is the price ? The problem is that I suspect it costs more than the trombone did, so it might not be a good fit.

I think the leather might not be enough, I tried some lighter cloth already but this wasn't enough. But this gives me another idea I could try for cheap , some black tape could do the trick. Maybe it is to light but maybe not. At least it doesn't cost much.

Another idea I had was giving it a little plastic deformation at the right spot to get rid of the resonance completely (instead of just damping). Problem is I don't know where to hit it and if it would help at all. Although one dent more would be no problem (it still has many although the worst ones are gone) I would not like to dent it pointlessly. Does anyone have experience with such a "modification"?

I really wonder how this strange behaviour comes about in the first place.
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Nomsis
Posts: 149
Joined: Feb 02, 2022

by Nomsis »

[quote="ghmerrill"]As a quick trial, you might try "vet wrap", though it's now not popular to refer to it as that and you might have to look for "self-adhesive bandage" or "self-adherent wrap" or some such. That would at least show you what the effect of a similar sort of "dampener" would have, and you could either stick with it ( :lol: ) or try something else. There are various sorts of (smooth flexible plastic) shelf/drawer liners out of which it would be pretty easy to make something (even with using some self-adhesive Velcro strips on the wrap so you could put it on and take it off). The major drug stores carry the self-adhesive bandage or you can get it from Amazon.[/quote]

haha, just had a very similar idea, see post above. I will try some "panzertape"
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ghmerrill
Posts: 2193
Joined: Apr 02, 2018

by ghmerrill »

You sure it isn't a loose solder joint? Or bell wire?
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StephenK
Posts: 171
Joined: Mar 26, 2018

by StephenK »

[quote="Nomsis"]Thanks for your interesting suggestions. The tone halo looks like a very interesting toy to play around. Where could I buy this (I'm located in Germany) and what is the price ?[/quote]

I think it's around £100, maybe less. Its from UK. Follow the link in the post.
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Nomsis
Posts: 149
Joined: Feb 02, 2022

by Nomsis »

[quote="StephenK"]<QUOTE author="Nomsis" post_id="241787" time="1714489278" user_id="14893">
Thanks for your interesting suggestions. The tone halo looks like a very interesting toy to play around. Where could I buy this (I'm located in Germany) and what is the price ?[/quote]

I think it's around £100, maybe less. Its from UK. Follow the link in the post.
</QUOTE>
Thanks, I couldn't see any price on the website. So it is as suspected, more than the trombone did cost. I'll save the link, it really looks cool. Maybe I will "need" this in the future for another instrument.

[quote="ghmerrill"]You sure it isn't a loose solder joint? Or bell wire?[/quote]

I will check it again when I'm at home but I'm pretty sure those are solid.
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timothy42b
Posts: 1812
Joined: Mar 27, 2018

by timothy42b »

[quote="Nomsis"]This behavior happens just in a very specific frequency spot on a well tuned c.

This is just like when one sings in resonance with a good wine glass.

It is a little annoying because it makes this tone very unresponsive.

[/quote]

That's exactly as you should expect. A mechanical resonance always sucks energy out of the system, though this one seems unusually extreme. I would not have thought it made that much difference to the wind column vibration.

Out of curiosity, can you tell if it's the middle C fundamental, or some of the overtones? Not that it matters.

Anyway, there are two approaches used in machine design. One is to lower the resonating frequency. Damping won't do that, you have to add mass. You always want to operate above a resonance, preferably way above. Look at a Bode diagram.

The second, and more common when the problem frequency is well defined, is a vibration absorber. That's a simple spring mass system at the problem frequency. It will vibrate instead of the bell. You might get lucky and be able to do it with a counterweight. And if not, a heavier counterweight might just shift the bell frequency low enough.
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Doug_Elliott
Posts: 4155
Joined: Mar 22, 2018

by Doug_Elliott »

I never understand the point when somebody says "it costs more than the horn."

If you got the horn for free you wouldn't spend anything on it?
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harrisonreed
Posts: 6479
Joined: Aug 17, 2018

by harrisonreed »

[quote="bassbone1993"]<QUOTE author="harrisonreed" post_id="241784" time="1714486092" user_id="3642">
Screenshot_20191219-171055.png[/quote]

I wish they still made this, as I have very little skill to make this
</QUOTE>

It's easy to do. You sew a pattern of suede and Velcro display backing material along three sides (inside out), then pull it "inside out" through the open end, and close it by sewing a Velcro hook strip on. Sewing again around the outer edges and a few lines in the direction of the bell taper eliminates the pocket. The Velcro hook strip adheres to the display backing material.

You can double the layer of the backing material to make a heavier gauge.
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spencercarran
Posts: 689
Joined: Oct 17, 2020

by spencercarran »

[quote="Doug Elliott"]I never understand the point when somebody says "it costs more than the horn."

If you got the horn for free you wouldn't spend anything on it?[/quote]

On most of my musical instruments (and all of my bikes) I've spent more on subsequent maintenance/repair/modification than the initial purchase price. If I'm happy with the final total price for the thing I wind up with, all good.
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ssking2b
Posts: 487
Joined: Sep 29, 2018

by ssking2b »

I have a vintage 1964 Conn 88H with a similar resonance in rhe

Bell. The G overtone series makes the bell ring. I have used an AMR one on it for years, and the problem was solved. Howerver the AMR company is defunct now. I got the Calder-Pips Halo and it solved the issue, and looks food on the horn.
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timbone
Posts: 240
Joined: Apr 30, 2018

by timbone »

You should enjoy the resonance of that bell- that is where the sound lights up.
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Nomsis
Posts: 149
Joined: Feb 02, 2022

by Nomsis »

[quote="Doug Elliott"]I never understand the point when somebody says "it costs more than the horn."

If you got the horn for free you wouldn't spend anything on it?[/quote]

The thing with this instrument is, it has many more problems like pretty strange intonation, strange mouthpiece receiver, mediocre slide, bad balance (it has the tuning slide brace and counterweight ripped out, really wonder how that happened), is assembled skewy, has plenty dings and dongs and some other quirks.

In short, I think for the money needed to make this a somewhat good instrument i could buy something way better. Thus I decided to not invest not much money in this instrument, it serves it purpose for me as something like a beater instrument for marching.

For my tape experiments, it is really strange, if I apply it tightly with a good fit it looks quite nice but it does nothing in preventing the bell vibrations. If I apply it really crinkly, lose and messy it looks very horrible but the vibrations are gone completely. Not sure if I can live with the horrible look though.
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Doug_Elliott
Posts: 4155
Joined: Mar 22, 2018

by Doug_Elliott »

With bad assembly and a missing brace, it sounds like you're chasing a symptom far removed from the actual cause. If you like the way it plays with "crinkly, lose and messy" tape - go for it.
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harrisonreed
Posts: 6479
Joined: Aug 17, 2018

by harrisonreed »

[quote="Nomsis"]<QUOTE author="Doug Elliott" post_id="241811" time="1714507121" user_id="51">
I never understand the point when somebody says "it costs more than the horn."

If you got the horn for free you wouldn't spend anything on it?[/quote]

The thing with this instrument is, it has many more problems like pretty strange intonation, strange mouthpiece receiver, mediocre slide, bad balance (it has the tuning slide brace and counterweight ripped out, really wonder how that happened), is assembled skewy, has plenty dings and dongs and some other quirks.

In short, I think for the money needed to make this a somewhat good instrument i could buy something way better. Thus I decided to not invest not much money in this instrument, it serves it purpose for me as something like a beater instrument for marching.

For my tape experiments, it is really strange, if I apply it tightly with a good fit it looks quite nice but it does nothing in preventing the bell vibrations. If I apply it really crinkly, lose and messy it looks very horrible but the vibrations are gone completely. Not sure if I can live with the horrible look though.
</QUOTE>

That trombone sounds awful! <EMOJI seq="1f62d" tseq="1f62d">😭</EMOJI>
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Nomsis
Posts: 149
Joined: Feb 02, 2022

by Nomsis »

I got this instrument in a very bad shape from a flea market and it was bend and damaged in almost every imaginable way, expect the slide was in an almost ok state and all the dents were not to bad. But it had one brace loose and the other missing and was very skewed. I gave it to my tech and he did a minimal effort to bring it in a playable state. Considering the price and history I think it has turned out very good. Sound is not bad, it cuts trough very well, somehow jazzy. I think the sound would fit a lead trombone in big band very well. Slide is very playable (but not great). The rest is not that great (: but it looks very cool! I really wonder how it played in its original state.

Considering the look, when I go marching with it I usually play in the first row and everyone can see it, that's why I'm unsure with the the tape...
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Nomsis
Posts: 149
Joined: Feb 02, 2022

by Nomsis »