Gap - Adjustable Gap Receiver - No Gap

[bbocaner]

My B&S CC Tuba too has no "bump" at the end of the receiver and beginning of the mouthpipe tube. Instead there is a counterbore in the mouthpiece receiver which allows for the wall thickness of the leadpipe and a flush transition.

This seems to be a common factor with the B&S Markneukirchen factory where post-2007 Bessons are also made. I'd be interested to check out a modern Meinl-Weston tuba to see if it had the same thing.

So there is not a physical „gap“ but a point where the taper in the receiver converges with the taper of the leadpipe. Unquestionably there must be a point where the taper stops getting smaller and where the tube starts getting larger.

right. well, the receiver gets smaller, but the mouthpiece backbore gets larger. And the leadpipe usually only gets larger. Usually the mouthpiece goes almost all of the way into the receiver, so at most you'd have a few mm where it's still getting smaller, however this few mm is right after the big step up in diameter from the end of the mouthpiece. And my theory is that the "gap" is more about marrying the expanding taper of the mouthpiece backbore with the expanding taper of the leadpipe at just the right spot, and that this little section of contracting bore at the very end of the receiver is relatively unimportant.

(I presume that we have a conical bore in the leadpipe of our Euphoniums. too. Of course(?) this is not the case on a trumpet because of the cylindrical shape of the leadpipe. But on a trumpet too there are two tapers - conical and cylindrical, gap in between - that meet.)

Trumpets have very conical leadpipes, too. You can actually see it from the outside.

[iiipopes]

I am not a fan of adjustible gap receivers, either. To me, it is just too much stuff in the way. However, it has been demonstrated for me, and I have demonstrated it to others, that different gaps can produce different playing characteristics with the same mouthpiece and horn combination. I know I'm restating the obvious next, but it does bear repeating, since all receivers and mouthpiece shanks do have manufacturing tolerances, assembly tolerances, and wear over time.

If the relationship between the mouthpiece and the receiver is comparatively large shank and smaller receiver, so that the mouthpiece doesn't go in as far as it needs to, then obviously one solution is to check to see if the receiver was reamed properly coming out of the factory, and adjust as necessary, a speck at a time, until the "sweet" spot balance between the characteristics listed above for the preference of the player is achieved.

If the relationship between the mouthpiece and the receiver is comparatively small shank and larger receiver, then the receiver should be checked to see if it is either worn, or was, again, not installed or reamed properly at the factory. Without resorting to "Reeves Sleeves" to make the mouthpiece shank larger, the player will have to decide if replacing the receiver is cost effective for the situation.

To experiment with gap, I use a very low-tech method: scotch tape or masking tape around the mouthpiece shank. Obviously, a person has to be careful to not let the tape get loose in the receiver and cause its own problems, and a little goes a long way with its effect on gap. But on a forty year old trumpet I purchased last year that had a great tone but wobbly intonation the worn receiver was diagnosed this way. With the addition of one neat simple layer of tape around the mouthpiece shank the desired intonation characteristics came back and everything centered very well indeed, with just the right width of slotting to make the horn flexible without being sloppy. Frankly, at less than a dollar a roll for masking tape, and since I don't play trumpet that often, it is not cost effective for me to replace the receiver on my trumpet, but the tape does just fine.

Other players' mileage and cost/benefit analysis will vary. I always encourage non-invasive experimentation.

[davewerden]

I am not a fan of adjustible gap receivers, either. To me, it is just too much stuff in the way. However, it has been demonstrated for me, and I have demonstrated it to others, that different gaps can produce different playing characteristics with the same mouthpiece and horn combination. I know I'm restating the obvious next, but it does bear repeating, since all receivers and mouthpiece shanks do have manufacturing tolerances, assembly tolerances, and wear over time.

I should have mentioned that you can order an Adams with a standard receiver if you like.

If the relationship between the mouthpiece and the receiver is comparatively large shank and smaller receiver, so that the mouthpiece doesn't go in as far as it needs to, then obviously one solution is to check to see if the receiver was reamed properly coming out of the factory, and adjust as necessary, a speck at a time, until the "sweet" spot balance between the characteristics listed above for the preference of the player is achieved.

Of course, that might be exactly what you do NOT want the next time you buy a mouthpiece of the same or different model/brand.

In that particular scenario, I would have a shop turn down the mouthpiece shank, not the receiver. You get to the same result without risking making your horn's receiver wrong for other mouthpieces.

[ghmerrill]

To experiment with gap, I use a very low-tech method: scotch tape or masking tape around the mouthpiece shank. Obviously, a person has to be careful to not let the tape get loose in the receiver and cause its own problems, and a little goes a long way with its effect on gap.

If you look in the right places on The Trombone Forum, you'll see some fairly detailed descriptions of how some people (including some professionals) adopt a similar approach with mouthpieces and trombone lead pipes and claim noticeable results. Rather than scotch or masking tape, the preferred medium is Teflon (plumber's) tape. Not as convenient, perhaps, as an adjustable gap receiver, but easy to do, and once you've got it set right on a mouthpiece/lead pipe combination, then you just need to replace it at reasonable intervals, which is pretty easy.

[iiipopes]

In that particular scenario, I would have a shop turn down the mouthpiece shank, not the receiver. You get to the same result without risking making your horn's receiver wrong for other mouthpieces.

Good point, if the receiver is to factory "spec" to begin with.

[ghmerrill]

The Kanstul shop will do this for you (and replate the mouthpiece). But they need to know what to turn it down to. So typically they need a mouthpiece with the shank size/taper that you want, and then they can turn your other one to those dimensions. Last time I had this done a few years ago I think it cost me $50 (plus shipping).

[RickF]

(snip)

Wide Gap (mouthpiece shank may be shorter)

• More Air Resistance
• Less Intonation Control
• Hard Slotting
• Less Flexibility
• Need Less Aperture Control

...emphasis below is mine
Medium Gap (Recommended)

• Medium Air Resistance
• Balanced Slotting & Flexibility

Small or Zero Gap (mouthpiece shank may be long)

• Less or No Air Resistance
• Considerable Intonation Control
• Loose Slotting
• Incredible Flexibility
• Need More Aperture Control

This discussion has been very interesting. Lately I've been having trouble with interval jumps in the upper register where I was chipping notes. I switched from G&W Kadja to the stock mpc for the M5050 BT-16 (by Demondrae Thurman). Much better slotting. The Kadja shank seems to be just a bit longer so maybe there is little or no gap. Slotting seems much better.

[John Morgan]

I tried various mouthpieces with my Miraphone M5050 when I got it a couple years ago. I, as did Rick above, ended up using the Thurman signature mpc that came with the horn and liked it so much, that I also ordered the same mpc with gold plating (I have used this mouthpiece for a couple years, including on my Wessex euphonium now while I await the new Adams). This mouthpiece has worked extremely well for me, so perhaps there was something to the specifications of this particular "signature" mouthpiece mated with this particular horn (Miraphone) - the right gap (or at least a very satisfactory gap) maybe being one of the factors, as I found slotting to be excellent with it. Slotting on the Wessex is not as easy with the Thurman mpc as it was on the Miraphone, but it could be partially for the rather obvious reason that the Wessex is a different horn with different leadpipe/receiver parameters.

[TheJH]

I tried an Adams a few years ago and I needed to have the receiver AT LEAST 4 or 5 turns out because I couldn't access the upper range of the instrument (that was an E1 .55 thickness) at all when the gap was 'closed'. the instrument also resonated better.
The pro of such an adjustable receiver is being able to fine-tune response and tone a bit without having to play uncomfortably or having to use a different mouthpiece because your main one doesn't work on a particular instrument.
The con I can think of is that you have to remember how many turns you want it to be unscrewed just in case someone else changes it for whatever reason.

[Art Lewis]

Within the last two weeks I´ve experimentetd with the gap. Gap size is hard to measure on my Euph because leadpipe and receiver are flush. But it seems to be very small or zero. The mouthpiece shank is pretty far in. Though I can´t compare it to another Euphonium MP receiver. The next Instrument from Finschhafen may be found in Lae (90 km from here) or even Port Moresby? Anyway; I used three sorts of sticky tape: Thin 3M Giftwrap Tape, black insulation tape and fairly thick red insulation tape. Results:
One layer of 3M brought the shank 1mm further out. Can´t feel a difference in blowing the horn. It feels different in a more psychological way: "Uh, there is some plastic between horn and MP... don´t like it..."
Two layers of 3M, shank 2mm further out: First impression was: "stiff". Like a bread dough on the stiff side. You like to add a bit of water to make it more smooth. High range was not so easy too.
Black insulation tape: shank 4mm out: My Euph lost to be agile, lithe. It didn´t respond or speek to me.
Red insulation tape: shank 6mm out: Not my instrument. The horn felt stiff, formal, forced. Tone quality was thin, airy, coated, hoarse... ugly.
Back to normal: What a relief! The horn came back to me, lost all the stubbornness. I played an hour on Bach´s Solo Suites and enjoyed not to feel any obstacles or gaps between Euphonium and me.
The experiment shows me: Putting tape around the MP shank changes playing my Euphonium a lot. Is it because of the wider gap? Is it because of damping through the tape? I wrote an Email to Paul Riggett and Gebr. Alexander/Mainz (because I´m about to buy the 151 Bariton Tuba) about their opinion. Have not got an answer yet and suspect they rely only on their profound experience.

[RickF]

Hi Art,

Not sure but it could be the dampening effect with tape added to your shank. I tried adding tape to the shank of my
Kadja mpc and it didn't seem to help in any way. I think there needs to be a solid connection between mpc and horn. Reminds me of the LefreQue sound bridge that is supposed to help.

[davewerden]

Good thought, Rick! I had not mentally related this to the sound bridge, but that makes perfect sense.

[Jrpetty24]

I tried an Adams a few years ago and I needed to have the receiver AT LEAST 4 or 5 turns out because I couldn't access the upper range of the instrument (that was an E1 .55 thickness) at all when the gap was 'closed'. the instrument also resonated better.
The pro of such an adjustable receiver is being able to fine-tune response and tone a bit without having to play uncomfortably or having to use a different mouthpiece because your main one doesn't work on a particular instrument.
The con I can think of is that you have to remember how many turns you want it to be unscrewed just in case someone else changes it for whatever reason.

It may have been mentioned or noticed in some peoples research..... but even Miel Adams stated most people settle around 4 or more turns. It's been so long since I set mine in place, but I remember mine being at least 4, and probably around 6 or 7 for my personal taste and setup.

[Art Lewis]

Have a look at the new Willson Saxhorn. It has a "BEM mouthpiece adapter ". I do not know how it works but they say it Individually adjusts the gap between end of mouthpiece taper and leadpipe. Interesting feature.

[franz]

Hi guys, in the last month i wanted to deepen the discussion of the gap ( as far as I am concerned). The gap should be the distance between the end of the backbore and the start of the leadpipe, where the receiver is welded on the leadpipe and therefore a "step" equal to the thickness of the leadpipe is created. Now, if I understand correctly, this generates an air turbulence more or less significant in relation to the increase or decrease of the gap, therefore more gap=more air resistance, less flexibility, less intonation control, while less gap=less air resistance, more flexibility and more control. In the trombone there is no welded receiver, but the mouthpiece is insert directly into the leadpipe, therefore no gap (0gap), while in euphonium and brasses in general, this gap exist ( but in my JP 374 baritone the receiver is welded to the leadpipe perfectly connected, so as not to leave any steps, but a perfectly smooth internal wall (0gap? I think it is a Sterling prerogative). Now, on my Prestige, looking inside the receiver, there is a double step with a very thin thickness ( between the two teeth there is a space of 2,5-3mm) but only on about half the diameter ( like a job done wrong). Now I have two almost identical K&G 3D mouthpieces and a third K&G 2,5E slightly dissimilar, I thinned the sten of the old 3D and the 2,5E in order to reduce the gap and make a comparison. So the original gap, which was 10mm for all 3 mps, was reduced to 5mm for the 2,5E annd 2,5mm for the old 3D. Ignoring the slightly different tone, due to different profiles and depht of the cups, I have not noticed significant differences, if anything a very slight resistance with the smaller gap but nothing more. So, to conclude, I think that when, in the coming months, I will order a Adams E3 will be without AGR. After reading the various opinions about Adams euphoniums in this forum, my Adams custom will be configured as follow:
E3 0,7 thickness silver plated, no AGR, key water only on main slide, vented valves, heavy cup on 4th and mother of pearls inlays buttons. I haven't decided yet whether to have a trigger: on Adams it shouldn't necessary, but in some cases it might be useful. My idea would be to order it with a trigger an an additional main slide to put in place of the original one when I need a lighter instrument to play standing or in marching services where the baritone is not suitable. Any suggestions?
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