Screw Bell and Intonation

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RBBERN01
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Screw Bell and Intonation

Post by RBBERN01 » Wed Oct 13, 2021 6:11 pm

Hi everyone, I’m thinking of having my trombone converted to a screw bell and was wondering what (if any) affect it would have on the intonation. My initial thought it the added weight would push it sharp but I have no idea if there’s any reality behind that.
Thanks all!
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Burgerbob
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Re: Screw Bell and Intonation

Post by Burgerbob » Wed Oct 13, 2021 6:38 pm

Honestly, it would be down to just the bell that was cut. I've never noticed a difference in intonation after a bell was cut.
mbarbier
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Re: Screw Bell and Intonation

Post by mbarbier » Wed Oct 13, 2021 7:03 pm

it didn't effect the pitch on mine, as far as i can tell. just slightly solidified the low range on a pretty light bell.
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hornbuilder
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Re: Screw Bell and Intonation

Post by hornbuilder » Wed Oct 13, 2021 8:54 pm

A screw bell conversion does not affect intonation in any way. Adding weight on the horn, no matter where it.may be, will not affect intonation, either. Intonation is affected by the internal shape of the sound path.
Matthew Walker
Owner/Craftsman, M&W Custom Trombones, LLC
Bass Trombonist, Opera Australia, 1991-2006
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RBBERN01
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Re: Screw Bell and Intonation

Post by RBBERN01 » Wed Oct 13, 2021 8:59 pm

hornbuilder wrote:
Wed Oct 13, 2021 8:54 pm
A screw bell conversion does not affect intonation in any way. Adding weight on the horn, no matter where it.may be, will not affect intonation, either. Intonation is affected by the internal shape of the sound path.
So intonation is only affected by the inn yet all shape of the horn? For some reason I feel like I remember hearing that simple changes such as adding weight or removing lacquer changed the sound and intonation of the horn. I’m not trying to argue, just hoping you can clarify things I may have been told that are wrong.
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BGuttman
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Re: Screw Bell and Intonation

Post by BGuttman » Wed Oct 13, 2021 11:40 pm

The weight around the throat of the bell may change projection, but should have no affect on intonation.
Bruce Guttman
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elmsandr
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Re: Screw Bell and Intonation

Post by elmsandr » Thu Oct 14, 2021 7:21 am

RBBERN01 wrote:
Wed Oct 13, 2021 8:59 pm
So intonation is only affected by the inn yet all shape of the horn? For some reason I feel like I remember hearing that simple changes such as adding weight or removing lacquer changed the sound and intonation of the horn. I’m not trying to argue, just hoping you can clarify things I may have been told that are wrong.
Pretty much.. it is physics. Length, linear density of the air, speed of sound... that's about it. That said; it could change how you play and thus cause you to change your portion of the wind column. If the balance of the horn changes on you and that causes you to pinch and pull your face around to find the horn, you can change your input and adjust the pitch. But if you can pay attention and keep the embouchure portion the same, the mass of the bell ring won't do anything to the length of the column.

Cheers,
Andy
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Re: Screw Bell and Intonation

Post by hornbuilder » Thu Oct 14, 2021 10:12 am

Quote "I feel like I remember hearing that simple changes such as adding weight or removing lacquer changed the sound and intonation of the horn"

This is a prime example of "Internet Knowledge" becoming "truth". The person that talked about weight changing intonation was entirely convinced he was right, but was completely wrong. Adding or removing weight "can" change sound, but it will not influence intonation.
Matthew Walker
Owner/Craftsman, M&W Custom Trombones, LLC
Bass Trombonist, Opera Australia, 1991-2006
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RBBERN01
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Re: Screw Bell and Intonation

Post by RBBERN01 » Thu Oct 14, 2021 2:58 pm

Thank you all for clarifying for me. Like I said, that is something I heard long ago and just never really second guessed or put much further thought into it. Since I’m starting to look more into modifications like that I thought I’d ask here and get clarification.
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