Talk to me about AGR

[chronolith]

So... some rudimentary research shows that adjustable gap receivers are closer to snake oil than actual magical unicorns by most accounts. It's up there with heavy valve caps, silver vs. lacquer, and turning the mouthpiece 90 degrees in terms of measurable mechanical fixes for things.

But I have some weird evidence that I do not know now to plug into my usual approach of fixing myself rather than the instrument.

I have a mouthpiece adapter, made by Wessex (can't find it on their website anymore) that I used on one of my side horns with an American shank mouthpiece thinking it would push it out a little more since normally I use Euro shanks.

I switched out the mouthpiece for a Euro shank but accidentally left the adapter in the horn, played a bit and thought I finally found the right mouthpiece for the horn. Great. In fact the horn never sounded better and there was a big reduction in the troublesome notes I had gotten used to.

I noticed the adapter was still in and removed it, going back to my regular setup (Euro without adapter). Felt like the old horn again, and it's usual quirks. Of course I thought maybe there was a mouthpiece placebo thing happening and assumed I was the problem, but then I put the adapter back in and things changed again for the better.

So now I am thinking there may be something to the idea of having that gap adjusted. I did a blind test with a couple of mouthpieces (and the patient assistance of my wife) and I could always pick out the setup with the adapter. In general the horn always played better (for me) with a Euro mouthpiece and the adapter.

And now I am wondering if the gap really does need to be fine tuned. I'm in no hurry to hack up the horn but I am just not sure how best to interpret the results I am getting. I have no interest in fueling any fires about AGRs fixing anything. What else should I be accounting for?

[Donn]

What kind of gap do you get, physically? Is the receiver interior flush with the leadpipe interior, or is there a step (and if so, which way - leadpipe is larger or smaller)? I guess the adapter is similar in effect to the mouthpiece shank - the interior diameter steps up after the adapter - so you would have 2 steps up, before the leadpipe? Probably none of these steps are very large, relative to the total interior diameter?

If you could make a functionally similar adapter out of materials at hand, you could experiment with length and thickness.

[bort]

I have an AGR on my Willson, because a previous owner decided he wanted to have one on there. I don't think I've ever noticed a difference in response, etc. based on adjustments made to the AGR. Maybe I'm not a good enough player (or active enough right now to notice the subtleties). Or, maybe it's better suited for smaller tubas, or tubas that give more response to the player. We all know that Willsons don't particularly give a lot of feedback to the player!

It's actually a pretty strange thing to have an AGR on a tuba when you buy it, because it's just one more variable to try and control. Sure, I messed around with it at first, but then I largely just forgot about it and left it alone. Honestly, I have no clue what setting it's even at right now. Going back to it after a while and after learning the nuances of my tuba... it's still just "one more thing," and not something I'm likely to use very much, or even at all.

The best benefit of the AGR for me is that I can use either Euro or American shank mouthpieces. However, it's annoying to remove the AGR and swap out the bit, so I almost never do that. Not to mention, if you DID have the AGR dialed into some magical location, there's no real way to tell where you have it located... so it's sort of like set it, and then never touch it again.

Worst thing is that some mouthpieces fit funny, no matter what. G&W mouthpieces with the "bump" at the shank/cup intersection (like the Baer MMVI) almost don't fit. The standard shank G&W doesn't fit in the standard AGR bit, you need to use the Euro bit... and that fit is kind of funny. The Euro G&W didn't fit at all (I think...? Whatever it was, it was annoying and didn't really work out.) Monette mouthpieces also barely fit into the AGR bit, but then again they have shorter shanks.

Honestly, I'd be happier with the stock receiver. I've considered reinstalling it, but I'm not sure what might have been done to the leadpipe when installing the AGR (any trimming, etc.). Seems like I spend a lot of time and money un-modifying (or re-modifying) other peoples' modifications to this tuba!

[chronolith]

It should be easy enough to get the mouthpiece and adapter under a good light and magnifier to determine what the difference is with and without. How that manifests as a gap in the receiver seems less simple. Is there a way to get a really good read on it that does not involve surgical cameras? Measuring the end of the mouthpiece (with and without adapter) to the insertion mark is simple but how do I measure that against what is happening inside the receiver? If there is no step it will be even more difficult.

Bloke, yeah I don't intend to modify (ruin) the horn with some kind of receiver replacement or AGR. I'm just trying to figure out if I am a fool or not for not considering it as an option.

I appreciate the wisdom.

[chronolith]

Borty,

I am sensing that the adapter in use may be a much larger change in length than can be offered by an AGR so that may be part of the scenario. I hope not though because then it will feel like I am in "magic dent" territory.

[Ben]

I have one on my Alex 163. The horn was purchased with 50 year old rotted leadpipe and over-sized Alex receiver, and upon overhaul I opted to have one installed at the same time as the new leadpipe was fashioned.

Here are the observations you are interested in:
1. There is an ideal position for my preferred MP.
2. I RARELY adjust it.
3. Depending on what playing shape I am in, I find adjusting it one way can clean up a troublesome attack on a note, or the other way to ease a slur issue I am having.
Out: can increase the sharpness of the attack. In/closed: can easy a troublesome slur. - It is a balancing act.

4. Typically when in peak or close to peak shape, I don't think about these things.

5. On horns with out the AGR - I don't miss it.

When you are in NYC next, stop in.

[Matt Walters]

First, the patented Dillon Adjustable Gap Receiver (AGR) is now back in stock and we are keeping the price the same $175 it has always been. It will be posted on our new website in a week or so. I need to write some copy for it first. Since that is a week or so away and this came up on TubeNet, I thought I would put some information out there on TubeNet about the AGR.

While most drivers don’t know they have a tire with low pressure until the light comes on in the dashboard, Professional race car drivers can tell the difference in the handling of a car with as little as ¼ PSI difference in the tire pressure of a tire.
Well, some tuba players can tell the difference in response (articulation) that a small fractional change in the receiver gap creates. MOST tuba players don’t know how bad they sound so they won’t be able to get any benefit out of something as subtle as a receiver gap change. (Please don’t think I am being holier than thou as I know full well how low on the totem pole I sit as a tuba player. I get to hear some of the best players in the world come through our store.) So, who is the Dillon AGR for? Lets start with who it isn’t for.

If think your tuba SUCKS, installing a Dillon AGR will not un-suck it. If your tuba plays naturally out of tune, the Dillon AGR won’t make it play automatically in-tune. If your neighbors think what they are hearing is a badly played bag pipe when in fact you are playing your tuba, the Dillon AGR won’t fix that. I have indeed seen the Dillon AGR installed on some very bad tubas. Let me put it to you straight. The Dillon AGR has never made a good horn into a turd. The Dillon AGR has never made a turd of a horn into a beautiful princess with a golden voice. AND…the Dillon AGR has never made a bad player sound great. Some people will sound like crap no matter what you put in their hands. So who is the Dillon AGR for?

If you have a mouthpiece that you like but you hear too much “foooo” in the beginning followed by the bloom of the sound, i.e. “fooWHAAAH”, that is indicative of too little gap for your personal style of articulation, instrument, and mouthpiece set up. The Dillon AGR after installed will let you increase the gap (space between the end of the mouthpiece shank and beginning of the leadpipe proper) until you can get a solid block of sound right from the beginning of the articulation. “tAAAHHH”. If you get a stutter, “Ta….AHHHH” in the sound when you articulate a half note, then you have too much gap happening for your personal genetics/style of playing and the instrument mouthpiece combination. With the Dillon AGR installed correctly, you can minimize the gap all the way to zero gap if need be.

Too little or too much gap and your playing won’t come out clean to the audience or audition committee without you doing herculean effort to compensate. The number one thing I hear from the GOOD players who talk to me after they didn’t get advanced to the finals and/or get the job is, “The audition committee said I didn’t play cleanly enough.”
If you have a good tuba that is in-tune, has a nice sound, but doesn’t articulate cleanly for you playing it on that one mouthpiece that you love, the one mouthpiece that feels so comfortable that you keep coming back to it, then a Dillon AGR is for you.

For the rest of you, keep buying expensive mouthpiece, after mouthpiece, after mouthpiece because you are trying to find something different that works with your tuba but doesn’t bother your chops. And when you compare mouthpieces between manufacturers, you are also dealing with a different gap setting as mouthpiece makers don't always use the exact same size/length shanks even though they may all call them American or Euro shank. So was it the mouthpiece cup and rim or was it the slightly different shank which changed the receiver gap that made you pick one mouthpiece over the other?

[swillafew]

Seems like a good place on the horn to make everything fit together in an optimal fashion. It cost me 100 dollars to make a poor fitting horn work great.

[Donn]

MOST tuba players don’t know how bad they sound

Not sure I want to know!

Is there a way to get a really good read on it that does not involve surgical cameras? Measuring the end of the mouthpiece (with and without adapter) to the insertion mark is simple but how do I measure that against what is happening inside the receiver? If there is no step it will be even more difficult.

That's my question - there really might be no step. All I know is, you can poke something in there, and feel around. If the leadpipe ID is narrower than the receiver ID, then your unbent paper clip or whatever will run into it. With a little bend a the tip of the wire, you can also check for the reverse. As I understand the Gap concept, once you've determined that there isn't a significant narrowing at the leadpipe, your work is done - you can't have a gap without that.

The real question - exactly what are the acoustic phenomena behind this effect you observe, in enough detail that you can proceed to optimize it - is beyond the scope of this chapter.

[Three Valves]

I have a mouthpiece adapter, made by Wessex (can't find it on their website anymore) that I used on one of my side horns with an American shank mouthpiece thinking it would push it out a little more since normally I use Euro shanks.

That is a handy thing and I found no one else that made one.

Plenty of trumpet/trombone/f horn adapters but nix on tuba.

I have no comment on the sound, just the convenience of using USA shank mouthpieces on a Euro sank tuba.

[Dan Schultz]

Very well said, Matt.

[chronolith]

As to the difference I would say the quality of the sound is largely the same. The intonation is slightly better but not directly. Basically it just feels more "slotted" and confident in the attacks. The level of compression on the notes feels more solid and I can bang it right in tune better, or at least that is how it feels to me. Without the adapter it feels more like wider slot and a guessing game.

I'm a serious nobody in the tuba world (emphasis on serious) so I am not sure if I fall into that 99% who, well... should refrain from pestering audition committees. I still like to play at my highest standard though and I can very much feel the difference in this case of the gap.

I have work to do in order to better describe what is happening (and measurements). I will unbend the paperclip soon.

[MusicSmiths]

When I changed out the receiver on my Besson I messed around with trying to determine how long the leadpipe should be. I put varying amounts of electrical tape around the shank of a mouthpiece and was able to change the performance characteristics. So it may not be the "gap" that's the issue, but just the overall distance between the buzzing lips and the rest of the horn's nodes/anti-nodes... whatever physical properties that come into play.

[Alex C]

Many tubas have no gap to begin with. In these cases the leadpipe extends and becomes the mouthpiece receiver. In such cases an Adjustable Gap Reciever would have no gap to adjust. Moving the adjustable receiver would make the instrument sharper or flatter but would not have the effect of adjusting the gap between the end of the mouthpiece and the beginning of a leadpipe.

As to whether it works or not, many trumpet players swear by them.

[Donn]

Many tubas have no gap to begin with. In these cases the leadpipe extends and becomes the mouthpiece receiver. In such cases an Adjustable Gap Reciever would have no gap to adjust.

I understand that's also frequently how the receiver is made - even though the leadpipe does terminate short of the mouthpiece shank, the receiver is actually designed to accommodate the leadpipe and continue its inside diameter, not its outside diameter. So there's no gap. I've never pulled off a receiver and seen this myself, just going on hearsay and the appearance of my own receivers, where there's only a barely detectable seam.

[Doug Elliott]

Correct that many or even most tubas have nothing resembling a gap. Changing the length at that point, whether by different size shanks or by an AGR, can have an effect on response, feel, and intonation even more than overall pitch.

[Matt Walters]

Many tubas have no gap to begin with. In these cases the leadpipe extends and becomes the mouthpiece receiver. In such cases an Adjustable Gap Reciever would have no gap to adjust. Moving the adjustable receiver would make the instrument sharper or flatter but would not have the effect of adjusting the gap between the end of the mouthpiece and the beginning of a leadpipe.

Wrong on the installation and results. When you install an AGR on a leadpipe/sleeve combo like an Alexander tuba,very old Miraphone, very old Besson or Salvationist tuba where the leadpipe comes all the way out to the end of the mouthpiece sleeve, you heat the sleeve and drive it off the leadpipe with a stuck slide tool. The leadpipe/ sleeve combo installation is made by soldering at the back end of the sleeve and then forcing a tapered tool into the leadpipe opening to expand/ flare the mouthpiece entrance outwards to fit the sleeve thus allowing the leadpipe to accept a tapered shank mouthpiece. A mouthpiece receiver (AGR or fixed) is a self contained unit with the mouthpiece shank taper already machined in to it that is soldered onto the end of a leadpipe.

When installing an AGR on a horn with leadpipe/sleeve combo, you cut a little off the leadpipe (typically the section that was flared out after the sleeve was soldered in place) so that the new AGR will be installed leaving the final length the same as original plus or minus the adjusting length of the AGR. If done correctly, you can adjust back down to zero gap to play like original or add in gap to clean up articulation as needed.

[joh_tuba]

Can someone post a picture of what the gap looks like inside an AGR?

[Ben]

I will tonight, if my boroscope fits...

[tuubajussi]

Hmmm.... Do I get the same effect by wrapping some adhesive tape around the mouthpiece shank so that it does not go so deep in the receiver?

Juha