Mouthpiece Gap

[trumpet56]

[Louise Finch]

[JetJaguar]

[feedback@stomvi-usa]

[razeontherock]

I think this discussion is very worthwhile, and have some results from very extensive experimentation that may be of practical use to those still confused. Before engaging the conversation I feel compelled to qualify that this is a fine point, and someone starting the school year after not practicing over Summer vacation and now having blown out chops from marching band should spend their time practicing sensibly rather than mucking about trying to fine tune gap. Valid play testing requires stable playing, which is the result of solid mechanics and fundamentals. This can absolutely be achieved at any age and within a couple years of playing for the exceptional student, but a certain skill level is required to make sense of this.

Of the various ways to experiment with this, if you want to get confused and give up in frustration just try to dial in the best feel and resistance for you. Somewhat better is to play​ scales and such, searching for the most even sound from note to note, and throughout your range. (This point deserves to have a sidebar issue addressed:. practicing to achieve the most even tone possible throughout all registers is STILL an important component of sensible practice! Practicing on the right gap sure makes it a lot more rewarding, though.)

Another way to go about it is what I did first, once I bought a means to experiment with gap. At the time it was a mystery who made it, but it is now identified as Jim New's adjustable backbore, which does work. Gap does affect how well I can play my very highest notes, but testing via this method is tiring, burns up a lot of practice time that could be better spent, and requires the highest level of playing consistency, meaning it is the most subject to player variation and placebo effect.

I find if I start by tuning to a concert A in the staff, using a good tuner, then check my other octaves, then do the same with open C, Bb, and G, that whatever gap performs best in this test also performs best (or at least as well) as any other gap in all the other tests mentioned above. This idea of using a good tuner also needs some clarification: a snark doesn't count. Any app I've tried on my phone that claims to be accurate to one cent, is. However, when they register how far off a note is, they drastically overstate and are only reliable in telling you if you're flat or sharp, and by a little or a lot, but not really by how much. More importantly, none of this does any good unless you center the note with your eyes closed, maintain pitch, and only then open your eyes!! In other words, a tuner does not replace good ears, nor does it reduce the need for ear training. You need to play each note you test "where the horn really wants it" for this method of testing to be valid. Once you get used to doing this it goes a lot quicker than trying to write it out.

Using the above methods has produced quite surprising results, demonstrating to me that ideal gap for any mpc is unpredictable, and each needs to be tested, just like KO states.

The most surprising part to me is discovering that what makes me play best on the bandstand is the horn / mpc combo that plays the best in tune, not how it sounds or feels.

[jeancalo1198]

GR does speak about the GAP, here is a link

https://www.grmouthpieces.com/category-s/244.htm

Where he writes:


The Gap is a very critical area of the match between player, mouthpiece and instrument.
Variation in this system due to the taper in the receiver, age of the instrument, size of mouthpiece shank, and poor tolerances by manufactures can be an area for trouble.


GR Technologies has defined the Gap components and their working relationship
.
These components are the Mouthpiece Shank, Receiver, and Leadpipe.

Measurements:
1. Distance from the end of the receiver to the leadpipe venturi.
2. Engagement of the mouthpiece shank into the leadpipe.
3. Exit diameter of the mouthpiece shank.
4. Leadpipe venturi.
5. Exit wall thickness or the mouthpiece shank.
6. Internal diameter of the receiver.
We use a formula to set gap. A change of .001" on the diameter of the shank will cause a difference of about .020" in the gap distance.
You may need to take your horn and have a professional measure it. If you do it at home make sure you do it several times and your numbers repeat.
If these numbers are set exact to this formula you will have the optimum or Zero Gap.
If the gap is greater it is a positive (+) gap measurement and the result will be a bit more resistance, although, the horn will slot and speak well. If the gap is less it is a minus (-) gap measurement and the result will cause less resistance, as well as, difficulty slotting. Some players like this condition and prefer the gap to the minus side.
If your gap is measured correctly and you find it within
.030" of the Zero positions you should be fine.
Formula: Exit wall of mouthpiece (#5) multiplied times 5.
Example, exit wall of mouthpiece = .025" X 5=. 125" .
Next take Venturi (#4) and subtract it from the Receiver ID (#6). You will need to divide this number by “2” to find the” effective wall thickness” of the leadpipe, and finally multiply the” effective wall thickness” by 1.5.
Example, Venturi is .345" and Receiver ID is .385. Subtract .345 from .385 and divide it by 2, you get an effective leadpipe wall of .020, multiply it by 1.5 =.030" . Now add the .125 and .030 and you get a Zero Gap of .155.
We find this formula to work very well. If you are getting good results there is no need for change. If you make a change measure the gap and calculate the change. It is not expensive to have the Gap adjusted. We recommend you set your gap and leave it alone. Constant change in this area will cause your playing to be insecure.

There are companies out there who manufacture "sleeves" which fit on to an altered mouthpiece shank. These sleeves are supposed to offer the player options in gap adjustment. Our finding is that the sleeves on the market today do not meet their advertised spec, plus they have a major design flaw. These sleeves are secured to the mouthpiece shank using a rubber O ring. This O ring acts as an insulator which deadens accoustical feedback to the player, inhibiting response and overall performance. This is why sleeves are seldom used by working professionals. Your best option is a custom mouthpiece with the shank designed specifically for your horn, or have the horn adjusted to gap properly with your preferred mouthpiece manufacturer.

Blow Resistance

Blow resistance is the acoustical resistance created by the mouthpiece when playing the instrument.
Such resistance depends on the specific design of the cylindrical bore and the backbore.
The blow resistance number that we use is a ratio, which is a multiple of the trumpet bore velocity head.
The mouthpiece blow resistance affects the acoustical impedance of the resonating air column.
We use this when analyzing mouthpieces and matching the player to the mouthpiece.
The bore size alone doesn't provide enough information to accurately make a match of the mouthpiece, horn, and player.
Blow resistance is a function of diameter and length.
We also calculate the volume of each mouthpiece.
This includes the cup, bore and backbore.
_________________
Juan "Leo" Leonardo

[Type3B]

There is a lot of helpful technical information in the many posts in this thread, and most of it by people far more knowledgeable than I am. But I do know very well my own experience. I play a Stomvi Flex mouthpiece and a Stomvi S3 trumpet, and the difference when I change the size of the couplers is pronounced: notes are easier or harder to start; range is more open or more closed; intonation is more consistent or less consistent; sound quality differs. I could go on, but overall, when you find the correct gap FOR YOU ON YOUR EQUIPMENT, it becomes, as Stomvi says, "Simply easier to play."
_________________
2006 Buick Lucerne

[grune]

[chrisroyal]