Miyot

My brain hurts.

Trumpet guy

Pilczuk Pipes

Is this what you were talking about?

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Daniel Lan
"If you're not improving, you're falling behind." - My Trumpet Teacher, Steve
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Horns
Bach Strad 37 - Schilke 22, Wedge 3C
Bach TR300 (collecting dust)
Berkeley Cornet - Factory Moutphiece
Berkeley Picc. Trumpet - Factory Mouthpiece
Olds Ambassador Fullerton Trombone - Olds 12C

Vulgano Brother

Quoting from Fundamentals of Musical Acoustics by Arthur H. Benade, First Edition, 1976:

1. In any multi-resonance oscillating system, a given resonance peak can take part in the regime only if its own natural freguency differs from that of the nearest harmonic of the tone by an amount that is less than the half-amplitude bandwidth W1/2 of the peak.
2. Increasing the damping of a given mode of oscillation has two effects on the nature of the resonance curve: (a) the height of the peak is reduced, and (b) the width is increased by the same factor. These in turn have two opposing effects on the ability of the resonance to participate in a regime of oscillation: (1) a reduction in the height of the peak means that the influence of this resonance is reduced, and (2) for a given small amount of detuning, an increase of the width means that the peak is given additional influence over the regime.
3. In wind instruments it has been unambiguously verified that for reasonably small misalignments the benefits of increased resonance width usually offset the disadvantages of reduced peak height. This means that if a peak cannot be aligned quite perfectly, it is worthwhile to make sure that there is enough damping to give reasonable overlap of the peak with the closest sound component....

I would argue that the "misalignment" needed for an instrument to respond equally as well at a number of different frequencies of a given note (without some weird color and response changes) may be achieved, in part, through the gap. (There are enough existing misalignments in the instrument that permit us to play at centered pitch with different tunings even with no gap.)

If we think of the gap as being the spit on a "spitball" (baseball term--please Google if needed) then it makes sense that varying gaps still work.

High-strung instruments may be designed with a specific gap.

The most important function of the mouthpiece gap, however, in my belief, is that it keeps the mouthpiece seated so that it doesn't fall out if we tip our trumpet the wrong way!

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www.letsbuildhope.org

veery715

How would something which doesn't touch the mouthpiece (the gap) act to retain it in the receiver? The gap doesn't keep the piece in, the receiver taper does it.
The gap is determined by the depth of the leadpipe from the mouthpiece end of the receiver and how far the mouthpiece taper goes into the receiver before it seats. If the depth of the leadpipe inside the receiver is too short the mouthpiece will be loose. So in a sense the allowance for a gap makes it possible for slightly different mouthpieces to fit snugly w/o touching the leadpipe end.

__________________
Never play it the same way once.

Trumpets:
Lawler Bb / Stage 1 Calif Bb Special / Conn 12B / Getzen 990S / Hunter-Diamond II / Wild Thing /
Stage 1 California C / Mannheim (Chinese) / Benetone / 1934 Cleveland (HN White) 603 Silver Plate w/ Gold Bell / Jaeger NY
PUJE!!
Kanstul ZKT 1525 Flugelhorn
Cornets:
'77 B&H 921 Sovereign / '41 Conn 36A / King Super 20 Master / '68 Olds Ambassador / Conn 18A /
Easyplay (??) / King HN White 1904 Bb/A

rowuk

The gap is there for a different reason. It is a deliberate imperfection in the bore that starts in the mouthpiece backbore and continues with the leadpipe. The what really happens there is subject to debate. It may be a source of mild turbulence that affects the standing wave in the horn, it may be a deviation from standard horn theory that brings an inefficiency into the generation of sound to change the playing characteristics of the horn.

If I remember right, Schilke built his instruments with ZERO gap when using Schilke mouthpieces. They were always my reference for in-tuneness and slotting.

__________________
Whenever I feel blue, I start breathing again.

veery715

Rowuk,
Since you are one of the most knowledgeable participants here at TM, it is not without some hesitancy that I disagree with you, but with a zero gap any mouthpiece built a little small in the taper would butt up against the edge of the leadpipe and not seat correctly. Certainly there is an effect attributable to the gap, but do you really believe most horns are built to account for that effect and not to provide some clearance (headroom, maybe) for mouthpiece variation?

Fine pro horns made by folks who also make mouthpieces might be designed in order to achieve no gap with their pieces. I am sure the absence of a gap would be a good thing. If I am not mistaken there are horns with built-in mouthpieces, built for that very reason. But the gap on your average factory-built trumpet exists more, I believe, to accomodate manufacturing differences in mouthpieces.

__________________
Never play it the same way once.

Trumpets:
Lawler Bb / Stage 1 Calif Bb Special / Conn 12B / Getzen 990S / Hunter-Diamond II / Wild Thing /
Stage 1 California C / Mannheim (Chinese) / Benetone / 1934 Cleveland (HN White) 603 Silver Plate w/ Gold Bell / Jaeger NY
PUJE!!
Kanstul ZKT 1525 Flugelhorn
Cornets:
'77 B&H 921 Sovereign / '41 Conn 36A / King Super 20 Master / '68 Olds Ambassador / Conn 18A /
Easyplay (??) / King HN White 1904 Bb/A

Trumpet guy

OK, I've seen so much discussion about the effects of the bell, leadpipe, tuning slded, etc. but what about the valve body. How does the valve block affect the sound (apart from weight differences)?

__________________


Daniel Lan
"If you're not improving, you're falling behind." - My Trumpet Teacher, Steve
------------------------------------
Horns
Bach Strad 37 - Schilke 22, Wedge 3C
Bach TR300 (collecting dust)
Berkeley Cornet - Factory Moutphiece
Berkeley Picc. Trumpet - Factory Mouthpiece
Olds Ambassador Fullerton Trombone - Olds 12C

rowuk

Veery,
zero gap can be achieved by perfect seating of the mouthpiece OR by a thin wall at the end of the shank and beginning of the mouthpipe. The "gap" is generally a pretty big change in bore size for a fraction of an inch. Many claim it is the secret to slotting and response.
Monette does build integral mouthpieces into certain models, but I do not know if there is a gap hidden from view. On my Ajna2 Dave Monette exchanged a mouthpiece because there was not enough "gap".

__________________
Whenever I feel blue, I start breathing again.

Trumpet Dad

In the ITG newsletter, May 1979, trumpet maker Clifford Blackburn writes:

"Too much gap or no gap at all can make the high register more difficult, make the low register stuffy, cause an unevenness of sound, or can cause the sound to be harsh or unfocused."

He went on to say that he has found little if any change in intonation by adjusting the gap and that gaps that work best range from 1/16" to 3/16" with 1/8" being pretty much the standard.

There is another article in the December 1982 ITG, by Dennis Fleisher in which he describes his Master's thesis at the Eastman School of Music "The Trumpet Receiver Gap: An Acoustical Study". Using acoustical impedance measuring apparatus, Fleisher could not find any change in pitch by adjusting the receiver gap (the results were random), but he did say:

"The effect of a gap alteration on trumpet response was found to be register-dependent. Specifically, as the gap length decreases, the low register response improves and concurrently the high resister response diminishes. This was found to be true up to and including the point where the gap was eliminated. Conversely, as the gap length is increased (up to a maximum of 8.90 mm in this study), the upper register response improves while the lower register response is diminished."

MJ

Interesting stuff. Bill Adam would sometimes have me put a piece of paper in between the shank of my mp and receiver. I assume he wanted more gap.

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