Anyone ever done the Bobby Shew tweak on their own horn?

improver · Heavyweight Member Joined: 14 Mar 2004 Posts: 1426

I watched shew rtake a little tool and put it in the receiver take a couple pops and voila 150 beans open horn . I've known a few guys do this with their tight Bachs with success. Anyone done this?

JoeLoeffler · Veteran Member Joined: 20 Sep 2004 Posts: 240

Yes. It can definitely change how a horn plays to a surprisingly significant degree.

Response, articulation, blow feel, resonance, timbre all can be effected.

improver · Heavyweight Member Joined: 14 Mar 2004 Posts: 1426

Is that a positive thing?

JayKosta · Posted: Fri May 21, 2021 3:22 pm Post subject:

depends on how the horn is affected by the effects.
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Goldplate · Veteran Member Joined: 14 Sep 2004 Posts: 152

I don't imagine there is any going back, if you don't like the change it makes.

giakara

Steve Hollahan · Posted: Sat May 22, 2021 4:32 am Post subject: Opening end of leadpipe

I used a tapering mandrel to open my Bach37. The 25 standard only differs from 25-O is the opening is slightly larger on the latter.
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Divitt Trumpets · Posted: Sat May 22, 2021 7:14 am Post subject:

I have a version of that tool that I use as part of my dialing in process for my instruments.

You can go back to the way it was before, and the results may or may not be what you're looking for.
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mattdalton · Posted: Sat May 22, 2021 7:41 am Post subject:

Frost Custom Brass sells a venturi tool for this. http://www.frostcustombrass.net/tools.html

Of course having the tool and knowing exactly how to use it to real advantage - like Bobby Shew and Ewan Divitt can - are two different things.
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Tony Scodwell · Heavyweight Member Joined: 17 Oct 2005 Posts: 1936

Many (if not all) makers utilize this "adjustment" to adjust the blow to their personal specifications. On my Scodwell USA trumpets I routinely do this with my tapered tool and as careful as I am with all the dimensions, sometimes I feel the finished trumpet will benefit from a slight (I call it burnishing) the venturi to get the blow where I feel it should be. Yamaha makes very good instruments but as mentioned, Shew will do a similar operation on the horns made with his name as factorys simply don't have the time to adjust each horn. I've always felt I have an advantage as each of my horns are made one at a time and played throughout the assembly by a top line player. When they leave my shop I am happy with the final product.

Tony Scodwell
www.scodwellusa.com

improver · Heavyweight Member Joined: 14 Mar 2004 Posts: 1426

Tony this is fascinating. So you're saying that new horns in many manufacturers have this tool to open up blow to where they want it?

JayKosta · Posted: Sun May 23, 2021 5:23 am Post subject:

Tony Scodwell · Heavyweight Member Joined: 17 Oct 2005 Posts: 1936

I can only speak with certainty about the process that Kanstul used to insure leadpipe venturi openings were consistent. A sized reamer was inserted into the leadpipe venturi after the trumpet was completed. As I said in my earlier post, my way of finding what I consider the optimum blow (for me) is play testing each horn and using my tapered tool if needed. Again, as much as I keep dimensions as exact as possible variables exist and I play test each horn for long periods to obtain what I feel is the correct balance with this simple process. What the major makers do I would like to know.

Tony Scodwell
www.scodwellusa.com

highscreamer · Posted: Mon Jul 26, 2021 1:21 pm Post subject:

I have a few specific questions to gather opinions

Since the definition of a venturi is the narrowest portion between wider portions of tubing, doesn't widening the opening of a leadpipe, in fact, push the venturi further down the leadpipe?

Is it optimal to have the venturi at the opening of the leadpipe or does someone have an opinion that the venturi further down the leadpipe has produced positive attributes (and what are those attributes)?
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Divitt Trumpets · Posted: Mon Jul 26, 2021 1:42 pm Post subject:

highscreamer · Posted: Mon Jul 26, 2021 2:16 pm Post subject:

Ewan,
I would agree that the leadpipe will only expand a few mils while soldered in the receiver.

In one case, I replaced a leadpipe on a Wallace Eb. The original leadpipe was flaired out to .370" moving the venturi way down the tube. I recall the narrowest part of the tube was .350" diameter or so. It was done prior to soldering and the intent may have been to eliminate a step into the leadpipe as the opening to the leadpipe was tucked under the shoulder where the leadpipe butts to the receiver.

Another case where I have seen no step into the leadpipe was with an LA Olds Special with an integrated receiver. The end of the mouthpiece releases into the tube with a gradual taper down to a venturi about .300" away from the end of the mouthpiece. If I recall correctly, the diameter was .350" at the venturi.

It seems to me the net effect of the tapered end of the venturi tool effectively reduces the step into the leadpipe with burnishing, while the flat end enhances the step by mashing the end slightly. I had inferred from previous posts on this topic, Bobby only used the flat end of his tool. Did I get that wrong?
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Lou Gagliardi
HighScream Brass - highscream.com

HighScream Brass Brio and Dolce Models
Yamaha YTR-8335 LA Bb
1994 Bach Stradivarius 43 Sterling Silver / 25-O
Courtois 154R Flugelhorn
GR Mouthpieces: WB-Classic, WB-Studio-M

JoeLoeffler · Veteran Member Joined: 20 Sep 2004 Posts: 240

This tweak should not be confused with how a manufacturer initially sizes or refines the opening of a leadpipe assembly during manufacture.

The tweak that Shew and others employ does not appreciably change the dimensions of the opening of the leadpipe. It is likely that these changes could not really be measured at all. They are not reaming anything open, they are not hammering a tapered rod to “open” the venturi. (Perhaps gentle taps with a 2 ounce hammer.) What they are doing is making adjustments to change the way the horn responds. Adjustments can be made to the opening inside edge and the flat face of the leadpipe. Small adjustments! Usually rubbing very gently is all that is needed. You can go back and forth to dial things in.

Keep in mind- an instrument that has a quick response seems to have an “open blow” no matter how large the Venturi measures. In fact, often an instrument that has had a Venturi reamed open will play dead and feel stuffy. Making a Venturi smaller can often make a horn play with a much quicker response. The reflection from the leading edge of the leadpipe has a huge impact on response.

Steve Knows Trumpet

I have actually done this procedure as it was described to me back in the 90's when I had purchased my first 6310Z, brand new.

I did the procedure to that horn back then and this year I bought one of those old 6310Z model horns, used and again, I did "the tweak" as described to me for the purpose of opening up the horn" ever so slightly.

The impression I had of what one is trying to accomplish, physically to the end of the leadpipe was more to change the shape or contour of the inside edge of the end of the leadpipe and NOT to make the end of the leadpipe larger in any way.

The way it was described to me, this tweak, involved NO tapping of anything with a mallet, but just a very little, light hand work and test playing of the horn as you would go.

The effect was to give a more rounded contour to the inside edge of the leadpipe only. as I understand all of this. Apparently, the end of the leadpipe was left very squared off in manufacturing and the idea was to maybe burnish that edge down ever so slightly and maybe even remove some burrs that may have been left there when it was cut off.

I am not an instrument tech or repairman of any description. I went very slowly with a lot of play testing as I went in each case until I could say for sure "yeah, ok. I've begun to feel and hear the change I desire" and then I stopped.

It did make both horns play somewhat better for me. On my newer 6310Z I definitely felt that I was "rubbing down" some burrs or rough edges in there that I could definitely feel through the tool when I started to work.

In particular this tweak improved the response of this horn I have now in the lower register and helped me get notes below low C to low F# speak better and pedal tone playing is also markedly improved now. The response is slightly but noticeably better around the top of the staff, but not to any night and day degree.

Do I know what I'm talking about? Most likely not. Did I perform the tweak correctly? This is doubtful.

But, I can say that I didn't really hurt the playing characteristics of either horn in any way and in my own mind, at least, some things were a little bit improved, anyway.

So, yes. Bottom line, like many of you, I'm just a psycho trumpet nerd who will try just about anything to tweak a horn, mouthpiece or mute because we've heard its what a player we admire has (allegedly) done to his equipment to customize or improve it a bit.

So, yeah, if you're going to attempt this yourself, I would say go slow! No hammers!! and play test as you go, and when you get a result, good or bad, STOP! before you wreck your horn!! More is NOT better, for sure.
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kehaulani · Posted: Mon Sep 18, 2023 7:29 am Post subject:

I had my Bobby Shew horn tweaked by Bobby, himself. Really didn't make much of a difference to me.
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Man Of Constant Sorrow · Veteran Member Joined: 25 Jun 2023 Posts: 221

"Tweaker".

I kinda like the name.
Thinking of getting new business cards made, with that as my job description. That will supersede "Myth Debunker".

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