Do Leadpipes Fundamentally Kill Response?

[tombone21]

It seems to me that the aspect of the instrument that has been toiled over and had the most R&D put into by manufacturers is the overall response or resonance of an instrument. Starting maybe with instrument techs taking off those 2 bell braces on Bach f attachments, the heavier mouthpiece trend (and back to the lighter mouthpiece trend we can see now), heavier bells in the 90s (that also has come back to bells trending lighter), edge bracing in the 2000s, then Edwards' harmonic brace. Now we're seeing a greater variance in valve cap material (even wood!) and Ultimate Brass' development of Resonance-Enhanced mouthpieces.

What part of the instrument can still be improved? If the first point of response comes from the vibrating lips, then transfers to the mouthpiece, the next part of the instrument is the leadpipe. The venturi in every leadpipe means that only the end of the leadpipe and the leadpipe collar are in contact with the inner slide tube. If there was a way to mill a leadpipe out of a straight tube of brass that fits flush with the slide, could that alter the resonance and response of the entire instrument? Has this already been done? Maybe those longer Thein leadpipes that they offer on altos follow this idea?

[Elow]

From my understanding the shape that the venturi is helps give resistance so if you make it a straight tube then it would feel a lot different to play.

[mrdeacon]

Have you had a chance to try the long leadpipes? They do make a difference but honestly I'd use a stock Bach pipe any day over one of those.

It's a bit like how the tech for Long Island Brass makes his own heavyweight furreles without gaps. They're cool and sure do look nice but they are also fixing a problem which kind of doesn't exist. Those small gaps are part of the reason a Bach or Conn play the way they do.

All that said I'm always interested to see what new ideas people come up with! I just think the long leadpipe thing will go the way of the adjustable cup mouthpiece!

[cigmar]

Don't mean to go off topic but what is this Resonance-Enhanced mouthpiece from Ultimate Brass I'm hearing a lot about. Their website makes no mention of it and can't seem to find anything specific about it. Is it in their entire line, what is it, what does it claim to do, etc.

[Burgerbob]

Good thought, but it's already been done.

[ericcheng2005]

Don't mean to go off topic but what is this Resonance-Enhanced mouthpiece from Ultimate Brass I'm hearing a lot about. Their website makes no mention of it and can't seem to find anything specific about it. Is it in their entire line, what is it, what does it claim to do, etc.

https://trombonechat.com/viewtopic.php? ... ed#p116740

From a guy trying to sell his Resonance-Enhanced mp

[WilliamLang]

leadpipes haven't really killed response yet for anyone, no? Some players go with no leadpipe for awhile and come back, some do the opposite. it's all to taste and phsiology i guess, which now that i'm reading it is maybe a boring answer. it's cool people are trying stuff though!

i have two ultimate brass mouthpieces now, one regular, one "enhanced". they play fine, definitely on the light side compared with the Shires and Greg Black style I'm used to, and they honestly don't reinvent the wheel for me. I would place them closer to the Lindberg mouthpieces on a weirdly specific spectrum from Lindberg to Greg Black, if that's worth anything to anyone.

[paulyg]

If the first point of response comes from the vibrating lips, then transfers to the mouthpiece, the next part of the instrument is the leadpipe. The venturi in every leadpipe means that only the end of the leadpipe and the leadpipe collar are in contact with the inner slide tube. If there was a way to mill a leadpipe out of a straight tube of brass that fits flush with the slide, could that alter the resonance and response of the entire instrument? Has this already been done? Maybe those longer Thein leadpipes that they offer on altos follow this idea?

You're on the right track, but you are still missing the point. Sound is created by vibrating the air inside the instrument, not vibrating the instrument.

The instrument vibrating does color the sound, however. The harmonic response of the metal structures that comprise a brass instrument can contribute to a distinct timbre.

The largest effect of what you're suggesting (billet-machined leadpipe with a cylindrical outside dimension) would be to increase the mass of the instrument. This would make the instrument more resistant to sympathetically vibrating with the air column inside it, and cause it to feel more dead.

[LeTromboniste]

It would quite a bit of mass. It would also make it quite a bit more expensive to make on a large scale while preserving consistency.

[Burgerbob]

Again... this has already been done.

[Doug Elliott]

The most important part of any equipment is the hype.

"Ultimate"
"Megatone"
"Tone ring"
"Tone booster"
"Resonance"
"Enhanced"
etc
etc
etc

In the 1970's people got their mouthpiece "skeletonized" because it helped the resonance.

Then came heavy mouthpieces and heavy horns, because it helped the resonance.

Now lighter mouthpieces and horns are coming back, because it helps the resonance.

Which leadpipe? Long, short, yellow brass, red brass, sterling silver? Soldered or threaded? They all help the resonance.

If you don't play just like whoever your idol is, you have nobody to blame but your equipment.

[mrdeacon]

Good thought, but it's already been done.

Just to back up what Burgerbob is saying. This guy has been at the past couple ITF's and usually goes to other shows. He was the one I was referring to in my first post.

It's interesting... But again not many people are going for it over a traditional leadpipe.

[Dennis]

The most important part of any equipment is the hype.

"Megatone"

If you don't play just like whoever your idol is, you have nobody to blame but your equipment.

One of my teachers said, "Back in the old days we used to practice."

My favorite part of Bach's Megatone series was Selmer opening the throat a drill size along with the heavier cup. Are the tonal differences due to the larger throat or the added mass?

Because of the confounding of the effects, the answer is necessarily "yes."

[paulyg]

One of my teachers said, "Back in the old days we used to practice."

That being said, there's a reason we don't play hollowed-out ram's horns anymore.

[harrisonreed]

That leadpipe looks like an excuse

[Bonearzt]

From my understanding the shape that the venturi is helps give resistance so if you make it a straight tube then it would feel a lot different to play.

I believe his thought is for the outside of the leadpipe to match the inside of the upper tube incorporating the taper inside.

Probably be REALLY heavy and dead due to the extra mass.

IMHO the lead pipe/venturi/whateveryouwanttocallit is basically a continuation of the transition from the throat of the mouthpiece to the bore of the inner upper slide tube.
The "faster" the taper, meaning it opens up more rapidly, the less resistance it will impart.
As opposed to a "slow" taper that will increase the resistance felt.
Also, a long leadpipe will feel more resistant than a short one for similar reasons.

There is no lead pipe that actually "constricts" the airstream, this can be demonstrated by looking into the lead pipe or upper tube and viewing the end of the mouthpiece shank.

King came the closest with the 2 piece lead pipe/mouthpiece receiver assembly where the actual beginning of the pipe almost butts up against the mouthpiece shank similar to trumpets.

This is the limit of my knowledge regarding leadpipes.
My other thought is that no two pipes will play or feel exactly the same!!! Which it part of the black magic voodoo of them.
The ONLY way to find a pipe that works for you is to play absolute blind play tests in actual playing situations.
Cover any markings and just grab & play until you hit that magic "Oh Yeah!"


Eric

[Elow]

I believe his thought is for the outside of the leadpipe to match the inside of the upper tube incorporating the taper inside.

I can’t imagine how hard that would be to manufacture

[Bonearzt]

Outside probably machined to spec and a special $1000 reamer for the inner taper.

That's all...


Eric

[timothy42b]

IMHO the lead pipe/venturi/whateveryouwanttocallit is basically a continuation of the transition from the throat of the mouthpiece to the bore of the inner upper slide tube.
Eric

That is what I believe.

I have been careless enough to say so online and have taken some abuse for it.

[Doug Elliott]

What's to believe? It's pretty obvious to me.

But I guess I tend to think about those things more than most.

[Fridge]

How about just practicing? Seems like the age old way of playing better......from an old guy.

Fridge

[elmsandr]

What's to believe? It's pretty obvious to me.

But I guess I tend to think about those things more than most.

The distinction that Tim is referencing is whether or not there is a second venturi beyond the throat of the mouthpiece (there is).

The smallest point of the leadpipe is about 1/2" past the end of the mouthpiece on most horns. The min diameter of a LOT of leadpipes is smaller than the exit diameter of most moutpieces.

Don't believe me? Get something to measure it and check it.

Cheers,
Andy

[FOSSIL]

How about just practicing? Seems like the age old way of playing better......from an old guy.

Fridge

People don't buy into that one any more....gotta be some bit of equipment that fixes everything....

And to the OP...it's quite the opposite...leadpipes are a big part of response...very big.

I, of course, have the ultimate leadpipe...a two piece pipe made for Phil Teele..... he left SO MANY great notes in it...

Chris

[timothy42b]

What's to believe? It's pretty obvious to me.

But I guess I tend to think about those things more than most.

).

The smallest point of the leadpipe is about 1/2" past the end of the mouthpiece on most horns. The min diameter of a LOT of leadpipes is smaller than the exit diameter of most moutpieces.

We've had this discussion before. It will never be resolved. The best I can do is make the disagreement clear to those who are blessed enough not to remember the last time. We do get new people sometimes.

If you look at a leadpipe in cross section, the bore goes from wide to narrow to wide. At first glance that looks like a classical venturi and it is often referred to that way.

The reason it starts wide and gets narrow is it has to accommodate a tapered mouthpiece shank, which also starts wide and gets narrow.

The reason it widens out again is it has to smoothly transition to the inner slide.

The section that narrows contains the mouthpiece shank, and inside the mouthpiece the internal bore is widening through that section.

I contend that the function of a leadpipe is a smooth transition from mouthpiece throat to inner slide. If given some mouthpiece and leadpipe combinations there is a narrower spot in the leadpipe than in the mouthpiece it is not intentional but an accident of geometry. I have mouthpieces with thick metal in the shank that i doubt this happens for, but a in thinwalled mouthpiece it might occur. To be specific, I agree it is likely there is a spot in the leadpipe narrower than the outside diameter of the mouthpiece, but not so likely than the inside diameter of a mouthpiece.

I could be wrong. Anybody have a design drawing with dimensions?

I suspect that the way most leadpipes are made is to draw the widening exit section over a mandrel, and ream the entering mouthpiece section. I guess you could draw it in one operation but you'd need two mandrels I'd think. I would do it that way because I need the area the air touches to be very smooth but where the mouthpiece is doesn't matter as much.

[Burgerbob]

How about just practicing? Seems like the age old way of playing better......from an old guy.

Fridge

People don't buy into that one any more....gotta be some bit of equipment that fixes everything....

Ahh yes, the kids these days that just don't practice at all.

[Kbiggs]

IMHO the lead pipe/venturi/whateveryouwanttocallit is basically a continuation of the transition from the throat of the mouthpiece to the bore of the inner upper slide tube.
Eric

That is what I believe.

I have been careless enough to say so online and have taken some abuse for it.

What's to believe? It's pretty obvious to me.

But I guess I tend to think about those things more than most.

I’m not heaping abuse, just presenting an observation...

I remember John Sandhagen on the old forum observed that from the rim of the mouthpiece to the end of the leadpipe, there are actually two points of constriction: the throat of the mouthpiece, and the venturi portion of the leadpipe. I believe this is true. You can see it if you take a leadpipe out of the slide tube. There is a “waist” that can be seen after the receiver. The “waist” on the outside is where the venturi is on the inside. Another way to say it: between the mouthpiece throat and the leadpipe venturi, there is a “bulge.”

I have no idea what purpose this bulge serves, or how it affects the sound of the horn. (I can imagine, however, that the length of the bulge and the size of the venturi opening are critical.) All I know as a player is that it affects the way the horn plays. Some designs work better for me, others not so much. For the designer and manufacturer, however, I would think this is a critical area of the instrument.

[Doug Elliott]

It is a byproduct of fact that it has a tapered receiver. That "2nd venturi" is not an acoustical feature and is not necessary.

[paulyg]

It is a byproduct of fact that it has a tapered receiver. That "2nd venturi" is not an acoustical feature and is not necessary.

Whether or not the 2nd "venturi" is necessary, it certainly is an acoustic feature (if present). I'll try and concoct a more thorough explanation soon. To an above point, the leadpipe's function is not to "smooth the transition from backbore to slide tube."

[elmsandr]

We've had this discussion before. It will never be resolved. The best I can do is make the disagreement clear to those who are blessed enough not to remember the last time. We do get new people sometimes.

It could be resolved, I'm trying to tell you... but you hold on to this.

If you look at a leadpipe in cross section, the bore goes from wide to narrow to wide. At first glance that looks like a classical venturi and it is often referred to that way.

The reason it starts wide and gets narrow is it has to accommodate a tapered mouthpiece shank, which also starts wide and gets narrow.

The reason it widens out again is it has to smoothly transition to the inner slide.

The section that narrows contains the mouthpiece shank, and inside the mouthpiece the internal bore is widening through that section.

I contend that the function of a leadpipe is a smooth transition from mouthpiece throat to inner slide. If given some mouthpiece and leadpipe combinations there is a narrower spot in the leadpipe than in the mouthpiece it is not intentional but an accident of geometry. I have mouthpieces with thick metal in the shank that i doubt this happens for, but a in thinwalled mouthpiece it might occur. To be specific, I agree it is likely there is a spot in the leadpipe narrower than the outside diameter of the mouthpiece, but not so likely than the inside diameter of a mouthpiece.

I could be wrong. Anybody have a design drawing with dimensions?

One of these days I'll take a junk 6 1/2AL and leadpipe I have and have them cross-sectioned so that you can see this, but I am not around a tool room with enough free time to do that these days.

Yes, I do have design drawings with dimensions. They are not mine to share, so I will not (I, uh, probably shouldn't have them..). There is a designed constriction about 1/2" from the end of the mouthpiece. I have been paid to make that point in an instrument and used gages to specifically verify that dimension. Please believe me. Or, just figure out a way to measure it.. Accident of geometry or not, this point is there on virtually all one-piece trombone leadpipes and also on two piece, trumpet style leadpipes. The entire function of Reeves Sleeves is to optimize this gap.
https://trumpetmouthpiece.com/collectio ... or-trumpet
Link with some images from another trumpet maker to define what this gap does... Different construction issue, same basic geometry issue:
https://www.whyharrelson.com/jasons-blo ... reduce-gap

I suspect that the way most leadpipes are made is to draw the widening exit section over a mandrel, and ream the entering mouthpiece section. I guess you could draw it in one operation but you'd need two mandrels I'd think. I would do it that way because I need the area the air touches to be very smooth but where the mouthpiece is doesn't matter as much.

Not reamed, as that is a metal cutting operation, more of a burnishing/forming operation to get the mouthpiece taper in the correct location (again, I've been there, run that machine). Doing that at the right depth and measuring it accurately is a pain. Small errors move the point quite a bit (and in some cases change the diameter). My $0.02 is that the variance in measurement of this is a big portion of why we often say that leadpipes have a lot of variation. Also explains why some like Sam Burtis spend time adjusting the fit of the mouthpiece with teflon tape to set the depth in the horn. I think we do, at least theoretically, want your smooth transition without the secondary venturi... reality is that for our response we expect that second one to be there and it feels funny without it (Psst, lots of leadpipe makers have made one without it... The more 'standard' ones with that point at about a 1/2" out sell more). I would wager a large number of our design features on instruments are more based around what we as the players 'expect' rather than what we would theoretically prefer. Kinda a New Coke type response from us to the manufacturers. We say we prefer something, we test it blind and prefer it, but out in the world, we choose the less optimal design for some other reason.

Cheers,
Andy

[Thrawn22]

It's the money invested/spent that has the most impact on sound. After that it's how much bs you can spew to others to back up such an expenditure whilst convincing yourself the expenditure was worth it. I have a buddy that adheres to this philosophy.

This subject reminds me of the idea that engraving has an impact on how the bell responds and yadda yadda yadda. The evolution from very ornate artistic engraving to minimal engraving back to very decorative engraving.

Doug said it best, it's the hype.

[paulyg]

This subject reminds me of the idea that engraving has an impact on how the bell responds and yadda yadda yadda. The evolution from very ornate artistic engraving to minimal engraving back to very decorative engraving.

My guess is this had less to do with playing characteristics and more to do with Firing the Engravers -> No Engraving -> Mechanical Engravers.

[CharlieB]

The smallest point of the leadpipe is about 1/2" past the end of the mouthpiece on most horns. The min diameter of a LOT of leadpipes is smaller than the exit diameter of most moutpieces.
Don't believe me? Get something to measure it and check it.
Cheers,
Andy

I must have misunderstood. Out of curiosity, I just now measured the internal dimension of the necks of my several leadpipes and found them all to be significantly larger than that of the mouthpiece stem. The dimensions were of course equal at the contact point of the stem of the mouthpiece, but the leadpipes all expanded from there.

A leadpipe is not just a transition mechanism from the mouthpiece stem diameter to the slide inner diameter. It is a carefully designed venturi tube that works in conjunction with that other venturi (the mouthpiece) to shape the air stream. Designs of leadpipe shapes are as varied as the shapes of mouthpieces, and different leadpipes create different characteristics in the way a horn plays/sounds. Can those characteristics be predicted by measuring leadpipes? Only in a very general sense. The pipe is only one part of the mouthpiece-leadpipe-horn-embouchure combination; so, too many variables.

But the above is all about the internal shape of the leadpipe. The original poster wanted to know if a more massive leadpipe machined from a solid billet of brass would affect the performance of the horn. Yes. Anywhere you add mass to the horn it has an effect. Positive or negative? Don't know. It's all empirical. Given the impracticality of machining a solid billet leadpipe, we may never know.

[WilliamLang]

it's ok to talk about this stuff, and figure out what makes a difference and what doesn't.

there's some hype and some products that don't do much out there, but i don't think anyone is saying parts replace practice at all. they work together, or we'd just have free buzz competitions. there's no shame in trying to optimize the instrument.

today's trombonists practice just as much if not even more than past generations. that's just how it goes in most human endeavors.

[elmsandr]

...
Given the impracticality of machining a solid billet leadpipe, we may never know.

To bring up Aiden's point above, the MADpipe does exist... you can buy one today if you want:
https://www.facebook.com/MADBoneInc/

They even have this handy picture to illustrate this area and what they are trying to avoid:


Even has a picture and patent for it:


Cheers,
Andy

[tombone21]

...
Given the impracticality of machining a solid billet leadpipe, we may never know.

To bring up Aiden's point above, the MADpipe does exist... you can buy one today if you want:
https://www.facebook.com/MADBoneInc/

They even have this handy picture to illustrate this area and what they are trying to avoid:

Totally forgot about MADbone! Probably because I've never been able to try it in person but the design seems very interesting to me.
https://www.facebook.com/watch/?v=2474019842636731

Kinda reminds me of a Bach K valve before Thayer and Hagmann hit the scene. I guess the integration of the mouthpiece eliminates the "step" between the mouthpiece shank and leadpipe. I wonder if the effects would remain if it was just the leadpipe on its own. I'm sure they've already tried something like this, but making a product that is more familiar to the rest of the trombone community would probably gain more traction even if the effects are slightly minimized compared to the fully integrated system in the MADpipe.

If the length, material, venturi size and taper of the leadpipe make an undeniable difference, why wouldn't filling out out the "waist" of the leadpipe to connect the entire pipe to the rest of the horn?

[timothy42b]

The original poster wanted to know if a more massive leadpipe machined from a solid billet of brass would affect the performance of the horn. Yes. Anywhere you add mass to the horn it has an effect. Positive or negative? Don't know. It's all empirical. Given the impracticality of machining a solid billet leadpipe, we may never know.

If the OP wanted to change the mass to the leadpipe, but retain the same internal dimensions, it seems to me the only option is to change the material.

Possible metals and their density in pounds per cubic inch:

Magnesium .064
Brass .308
Silver .379
Lead .409
Gold .687

You aren't going to get much more dense than gold, even with the exotics like indium or osmium.

[elmsandr]

Totally forgot about MADbone! Probably because I've never been able to try it in person but the design seems very interesting to me.
https://www.facebook.com/watch/?v=2474019842636731

Kinda reminds me of a Bach K valve before Thayer and Hagmann hit the scene. I guess the integration of the mouthpiece eliminates the "step" between the mouthpiece shank and leadpipe. I wonder if the effects would remain if it was just the leadpipe on its own. I'm sure they've already tried something like this, but making a product that is more familiar to the rest of the trombone community would probably gain more traction even if the effects are slightly minimized compared to the fully integrated system in the MADpipe.

If the length, material, venturi size and taper of the leadpipe make an undeniable difference, why wouldn't filling out out the "waist" of the leadpipe to connect the entire pipe to the rest of the horn?

Just to nitpick... Bach's K valve came out about a decade after Thayers were introduced. The K valve was the reactionary one there.

I'm intrigued by his concept, I have just chosen to get off the Leadpipe rodeo trying to figure out what is going on there and work on blowing into the little end with what little time I have on the horn these days.

That said... my two favorite leadpipes:
1)Bass pipe made with the venturi ~ 1/2"-3/8" closer to the mouthpiece. This was an intentional process change on this pipe as a test.
2)Bach 50 Pipe that the mouthpiece sits in at least 1/8" farther than any other Bach pipe I have. Have not measured where exactly the venturi is on this or what the diameter is, but.....

Placebo? I don't know. I made a concious decision not to care about it anymore and just try to tongue and blow on this part. I am not good enough for this to make a difference even to what I repeatably hear, let alone other players or the audience.

Cheers,
Andy

[paulyg]

I will do my best to address this later in a more detailed way, but the idea of "shaping the airstream" is a complete cul-de-sac in terms of understanding the actual role of the leadpipe (or ANY construction element of a brass instrument).

[timothy42b]

the idea of "shaping the airstream" is a complete cul-de-sac in terms of understanding the actual role of the leadpipe (or ANY construction element of a brass instrument).

Agreed.

The air need not move at all.

What is shaped is where the sound wave travels.

Still probably want a smooth transition, though; any impedance change will give you a reflection where maybe you didn't want one.

[Doug Elliott]

In a general sense, smoother is better. The best instruments have less gaps, reversals, discontinuities, etc. Where a discontinuity like the "2nd venturi" exists, it's useful to consider the average contour of a longer area instead of focusing on the discontinuity itself.

[Thrawn22]

My guess is this had less to do with playing characteristics and more to do with Firing the Engravers -> No Engraving -> Mechanical Engravers.

True. Can't forget how money directs production.

[Kbiggs]

Placebo? I don't know. I made a concious decision not to care about it anymore and just try to tongue and blow on this part. I am not good enough for this to make a difference even to what I repeatably hear, let alone other players or the audience.

Cheers,
Andy

Maybe, maybe not. The placebo effect is real. But you’re right: “I made a concious decision not to care about it anymore and just try to tongue and blow on this part. I am not good enough for this to make a difference even to what I repeatably hear, let alone other players or the audience.”

[CharlieB]

I will do my best to address this later in a more detailed way, but the idea of "shaping the airstream" is a complete cul-de-sac in terms of understanding the actual role of the leadpipe (or ANY construction element of a brass instrument).

Thank you for that distinction.
A more accurate way of stating that would have been to say, "Modifying the compression pattern of the air stream."
Sound cannot travel in a vacuum because the waves are series of compressions and rarefactions that can only exist where there is matter. Solid, liquid or gaseous.....doesn't matter. In our case, it's moving air. The performance of the sound wave is affected by variations in the air density and velocity as it encounters changes in its travel path.The primary sound waves also create a sympathetic vibration of the horn, which in turn influences the pattern of the primary sound wave. Air traveling through a venturi is both accelerated and decompressed, which makes the size and shape of a venturi a significant factor in the character of the sound wave that eventually exits the horn. Short version: Changing pipes changes the sound.

[timothy42b]

The inner bore of a mouthpiece expands like a cone.

If there is a section of the leadpipe that is smaller past the point where the mouthpiece ends, I suspect it would intersect the size of the cone if you extended the mouthpiece cone. In effect, I think there is a gradual expansion of the bore more or less continuously from mouthpiece throat to inner slide, with a little uncertainty in the short section between end of mouthpiece and the point at which expansion of the leadpipe begins. Given that mouthpieces aren't all the same length, variations in manufacturing tolerances, etc., there's probably some slop in that area. I don't see any intent for it to function as an actual venturi.

If you wanted to control this completely, you could pull the leadpipe and use a mouthpiece with a 10 or 12 nch shank. !? but then the end of it would be so think it would deform easily.

[elmsandr]

The inner bore of a mouthpiece expands like a cone.

If there is a section of the leadpipe that is smaller past the point where the mouthpiece ends, I suspect it would intersect the size of the cone if you extended the mouthpiece cone. In effect, I think there is a gradual expansion of the bore more or less continuously from mouthpiece throat to inner slide, with a little uncertainty in the short section between end of mouthpiece and the point at which expansion of the leadpipe begins. Given that mouthpieces aren't all the same length, variations in manufacturing tolerances, etc., there's probably some slop in that area. I don't see any intent for it to function as an actual venturi.

If you wanted to control this completely, you could pull the leadpipe and use a mouthpiece with a 10 or 12 nch shank. !? but then the end of it would be so think it would deform easily.

So, as long as we are thinking rather than doing or measuring, some thought questions:

Mouthpieces aren't all the same length, but the gage line insertion and taper rate on the OD of the shank are all the same for a given family size. Aside from wall thickness at the end of the shank, the nominal opening size is roughly identical on all moutpieces of the same shank size, correct?

Is the minimum bore of a tenor .547 leadpipe the same size as a .562 bore bass leadpipe? Can we validate this?

If the goal is to continue the taper, all leadpipes for a given shank size should have the same minimum bore, can we verify this? Similar to above, an Alto trombone leadpipe would have the same minimum diameter in the leadpipe as a .525 horn then, right?

If all the diameters are the same, what exactly are manufacturers doing when they say pipes are tighter? Are they making different taper mandrels rather than just adjusting the intersection of the tapers to change the minimum diameter?

If the taper rates are what is different, why on earth are they almost all the same length?

Back to the real world, anybody seen those MADpipes in person, what is the wall thickness at the end? More like a mouthpiece or like a leadpipe?

Cheers,
Andy

[timothy42b]

So, as long as we are thinking rather than doing or measuring, some thought questions:

Aside from wall thickness at the end of the shank, the nominal opening size is roughly identical on all moutpieces of the same shank size, correct?

I can't measure, I've never changed a leadpipe. If something doesn't work right I figure I should practice more.

Aside from wall thickness the opening is identical? I have no idea what that means. Maybe I'm stupid. It seems to me if the OD is the same, and the wall thickness differs, then the ID will be different.

As everything else follows from that, I don't understand anything you typed, except that you want to call something a venturi that really looks like a cone to me. I concede. A leadpipe is a venturi until you put a mouthpiece into it so that's what we'll call it from now on. Done.

[elmsandr]

39D1B032-AFAF-4271-8219-906B6DF94CCA.jpeg

Some ‘measurements’, COVID edition... found a pen in the drawer really close to the diameter of the end of a Bach shank.

Fits in the 50B. (Checked 3 of 4 50B pipes downstairs, didn’t bother to check the funky one that I know isn’t like the others. Ages on pipes are from 1950, 1970, 2019. They all felt about the same.

2DB4595F-BE9F-43F6-9428-FA68C89C5065.jpeg

Doesn’t fit in the 42B. Didn’t dig out the other 547 pipes down stairs, That would have taken a bit more effort.

9841E811-6EB7-417E-9712-D4F4914F8322.jpeg

Not pictured.. maybe fits in my other favorite bass pipe. Could probably have forced it, not going to do that for this.

*don’t get sticks and pens stuck in your leadpipes, techs don’t need that extra work right now. Wish I had my old pin gage set about now.

Cheers,
Andy

[elmsandr]

From the King Bass trombone thread this little nugget about leadpipe design on the Duo gravis:

On the mouthpiece end of the horn George optimized taper by using his knowledge of trumpet
construction. Most trombones have the mouthpiece sit inside a "leadpipe" with a sudden drop to the
leadpipe bore at the small end of the mouthpiece. The new bass had a trumpet style leadpipe. The
mouthpiece receiver ends an acoustically insignificant distance from the near edge of the actual
leadpipe. To the acoustic flow, the end of the mouthpiece and beginning of leadpipe is "invisible."

Cheers,
Andy

[Bonearzt]

The inner bore of a mouthpiece expands like a cone.{/quote}

More or less, but not always a constant taper, the shape of the backbore is determined by the manufacturer for specific reasons discovered by experimentation.

Mouthpieces aren't all the same length, but the gage line insertion and taper rate on the OD of the shank are all the same for a given family size. Aside from wall thickness at the end of the shank, the nominal opening size is roughly identical on all moutpieces of the same shank size, correct?
Cheers,
Andy

No, the wall thickness at the end of the shank is a function of the end of the backbore at the end of the shank.
The taper rate & length, in most cases, determine how far in the shank sits, also depending on the size & taper of the receiving end of the leadpipe.

Eric

[elmsandr]

Mouthpieces aren't all the same length, but the gage line insertion and taper rate on the OD of the shank are all the same for a given family size. Aside from wall thickness at the end of the shank, the nominal opening size is roughly identical on all moutpieces of the same shank size, correct?
Cheers,
Andy

No, the wall thickness at the end of the shank is a function of the end of the backbore at the end of the shank.
The taper rate & length, in most cases, determine how far in the shank sits, also depending on the size & taper of the receiving end of the leadpipe.

Eric

Eh... I'm not sure what you are trying to say here. My point is that the mouthpiece taper is standardized. Small shank and large shank mouthpieces use a morse taper rate (if not the exact size in the machinery handbook).

Both small and large shank pieces sit nominially 1.0" into leadpipes. Wear and manufacturing variability aside, the nominal depth is the same. Thus, the OD of all small shank mouthpieces at the leadpipe interface is the same. Similar for Large shank pieces. The ID of that part does vary, but I will note that tends to vary by mouthpiece maker, not indivual specs. That is, all of my Bach mouthpieces seem to have the same wall thickness, regardless of size (6 1/2 - 30 CB), which is a little thicker than my Schilke pieces etc...

If a leadpipe is to just be a truncated cone, the tip of the cone has the same interface diameter for all leadpipes that have the same shank size. I think it is pretty clear they are NOT designed or existing as a truncated cone. We call them a venturi because there IS a venturi in there.

Cheers,
Andy