Gap, no gap and other mysteries of the pipes

Discussion in 'EC Downloading' started by ROGERIO, Jan 15, 2008.

  1. ROGERIO

    ROGERIO Mezzo Forte User

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    ED,

    Happy New Year!

    I remember you saying how your father (then later you) worked at the Schilke factory on Wabash… so I thought you might be the perfect person to ask…

    I'm going to be vague, intentionally! I'm not really a techno-weenie so I'm surprised I even care... but, here it goes:

    Why is it so important to address the mouthpiece and receiver gap issue on all our instruments except the flugel and cornet?? These instruments do not appear to have a "receiver" that offer the ledge to receive the mouthpiece end, just an open pipe.

    I'm not new to this game of ours, but for some reason I'm rather consumed by this question. I do understand the taper issue with flugel pieces... so there is no need to address that.

    Without mentioning brand names, I recently switched cornet mouthpieces from one that has a very fine "edge" (very thin end) to another that uses a rather large edge (thick end). The thin makes sense to me... a small variance from mouthpiece to leadpipe (leader pipe for the Brits), with little drop (or ledge).

    Okay, I'm chops enough to admit that I've noticed no ill effects from this "ledge". But then again it's an entirely different mouthpiece too.

    I have read Schilke's explanation on the relationship of mouthpiece and leader pipe on instruments with "conventional receivers", but the cornet and flugel style of receivers is not addressed. Leader Pipe and Its Function

    Thanks in advance for a reply.
     
  2. oldlou

    oldlou Forte User

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    In my extensive,( over forty ), vintage and fairly modern cornets I find none of them that was made with the receiver being anything other than a reinforcement of the leader pipe, with both tubes being flush at the opening. It seems to me that the early designers did this to keep the tapered shank of the mouthpiece from acting as a wedge and swedging the leaderpipe ever larger, which in effect would require ever larger diameter mouthpiece shanks.


    My trumpets, conversely, were all made with a seperate receiver tube which is fitted only a short distance over the leader pipe, thus, having a ledge at the end of the leader pipe, which can be found inside of the receiver. I have heard/read more than one reason for this to be, and also many versions of how to attain optimum 'clearance' to that ledge, and also more versions of the benefits of proper clearance and the ills to be discovered with improper clearance.


    My former boss and friend/mentor, A.J.'Bill' Johnson was the owner and chief designer at York Band Instruments for over forty years and was probably as knowledgeable as any man alive when I worked in his retail store and I was constantly being barraged by him with more and more of the science and history of brass musical instruments. He explained that the modern trumpet is nothing more than a "miss shapen cornet", with the leader pipe reinforcement not fully seated, thus, allowing a longer and larger O.D. mouthpiece shank, thus gaining some brilliance in tone caused by the altered backbore of the trumpet mouthpiece.


    OLDLOU>>
     
    Last edited: Jan 15, 2008
  3. rowuk

    rowuk Moderator Staff Member

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    If we compare the trumpet to a complex electrical circuit, the gap is an added capacitance. That means it affects only certain frequencies- More gap=lower frequency.

    The trumpet is a horn based amplifier and due to its construction, the uneven blow and intonation need to be compensated for. The gap is one way to partly accomplish this.

    It NEVER is the difference between good and bad, rather good and better.
    The more conical bore of a cornet or flugelhorn give us more leeway in design, and more forgiveness for minor discrepancies,
     
  4. ecarroll

    ecarroll Artist in Residence Staff Member

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    Rog,

    Happy new year to you too.

    Yes, my father worked at Schilke for a number of years and I did some seasonal time as a kid there as well. He wasn't a trumpet designer, however, and I was far too busy playing to ask many questions myself.

    My limited knowledge of this subject supports Robin's reply. My old Schilke mouthpieces (I'm still playing one that Scott Laskey made when he was there) are razor sharp on the tapered end, so I guess that I'm a small gap guy who prefers resistance caused by the venturi inside the horn.

    Mind the gap, mate
    EC
     
  5. ROGERIO

    ROGERIO Mezzo Forte User

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    Sep 30, 2004
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    ED, Old Lou and Robin,

    Thanks all but my "capacitor" remains limited... LOL

    I know there is a reason for the gap (whatever the heck that reason is)... but are you all saying that because of the conical nature of the cornet and flugel, that gap is no longer needed?

    Also, why would a MP with a thick end not affect the quality of sound on a non receiver horn... a literal "step" from the MP to the leadpipe woud seem problematic to me.

    Robin, you are a "brainy" kind of guy (and I mean that in the nicest way possible)... see if you can bring it down a few notches for me to understand... this gap thing first... then the conical and no gap theory.

    Were you trying to say that there is a direct conenction between a certain gap and the frequencies it affects? Is it a mix as in where a notal point hits coming out of the MP or is it more straight forward like bigger gap=better low, or smaller gap=better higher... guessing....

    If this stuff bores you all... or if you feel the need to BS... please feel free to NOT reply.... although I'm somewhat confussed already... I don't want to end up more confussed. Sometimes ignorance is bliss... and my time may be better spend playing with the little monsters...LOL (horns that is...).

    Thanks to all and to all a good night. It's 57 here in Phx and I'm cold... guess I've finally worked those upstate NY winters out of my blood.
     
  6. Eeviac

    Eeviac Piano User

    It's 30 outside here in Prescott (actually chino valley) and about 58 here in my room, and I know a capacitor is an "across variable" as per the old weird MIT physics book I wish I still had.... didn't go there just had this book.....

    Anyway, "like a capacitor" means, it's like that equalizer thing on the front of some boomboxes, where you can emphasize the higher end or the bass.... to change the tone. I think he's saying it's emphasizing the high end, more "tweeter" less "woofer"

    Nice to hear you're so toasty warm down there in PHX!
     
  7. rowuk

    rowuk Moderator Staff Member

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    Rogerio,
    think of a capacitor as a device that can affect specific frequencies. A GAP cap works two ways, with a small turbulence and the sudden increase in bore size.

    As the trumpet is an amplifier, anything that we do so close to the input end makes a much bigger difference by the time it gets to the bell (output).

    The gap introduces a frequency dependent filter that can smooth out small differences in blow (response) and intonation (frequency). More detail than this involves advanced math and modelling specific instruments.

    The Schilke horns traditionally did not have much of a gap. That is because Renold knew much more about leadpipe design and had control of the blow and intonation there. Bach instruments can often be improved by adjusting the gap and valves. Monette instruments are also finicky when the gap is not correct.

    A much as many claim that the gap should be X, it is really dependent on each individual horn and mouthpiece. Sometimes NONE is best.

    Conical bore instruments function a bit differently than trumpets. other things being equal, they are not as "resonant" and do not amplify as much. Therefore small changes do not have as much of an impact.

    Before any of you get on my back about your flugelhorns being so resonant, blah, blah, blah, give me a chance to explain. The resonance that I am talking about is called Q in physics. This is perceived as "slotting" when playing brass instruments. A trumpet has tighter slots (=more resonance) than a cornet or flugelhorn. The penetrating sound from conical instruments is due to the lack of overtones not "resonance".
     
  8. ROGERIO

    ROGERIO Mezzo Forte User

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    Thanks Robin... I'm a bit closer to grasping this... but I'm certain there is still a large "gap" between what you know and what I know... sorry, a little humor there.

    Eeviac, you are less than an hour away... come down and warm up a bit.
     
  9. ecarroll

    ecarroll Artist in Residence Staff Member

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    Sunny and 70 in Los Angeles (80 this past Friday)

    Blissfully,
    EC
     
  10. Vulgano Brother

    Vulgano Brother Moderator Staff Member

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    Most of us are guilty of stating speculation, theories and the like as fact; Vulgani are no exception, and it is a rare event when Vulgani admit to this. I would even go so far to say the following is nothing more than a (hopefully well thought out) hypothesis:

    With a conventional instrument, we play two instruments, not one. One is the mouthpiece, the other the trumpet itself. The interface is the receiver, and the gap separates the two components, and is, when of acceptable size, inconsequential. This last statement is based on the following:

    1. When placing a microphone before a trumpet bell, a distance equal to approximately one half of the bell diameter allows almost all frequencies to be recorded. In other words, this is a place where all the wavelengths meet. (see Arthur Benade, Fundamentals of Musical Acoustics.)
    2. Likewise, at a distance approximately one half of the shank diameter we might expect a similar meeting point.

    I propose that usable gaps are small enough that this meeting point occurs inside the leadpipe of the trumpet, in effect negating the gap.

    I have long held that there are two different and viable methods of sounding the trumpet. One is to use the trumpet as an amplifier, the other to sound the trumpet itself. (Monette mouthpieces prove exceptional at the later.) If we eliminate the gap, as in an integral mouthpiece (as found in the Monette Raja), or as Schilke recommended with a conventional instrument, we truly play a one piece instrument. This means, however, that the mouthpiece, with all its quirks and curves and flares becomes part of the trumpet equation—nasty stuff to figure out even with a computer.

    One of my instruments, a tricked-out (but not pimped out) bell-tunable C with a Bb bell has an adjustable receiver. I use a Curry BC cup short shank and a normal shank C cup mouthpiece (which have the same shank taper and end diameter) without any need for adjustment. I should add, for the most part, I like to perform playing the amplifying version of the trumpet for expression sake. (I tend to practice the sounding trumpet, however, which might explain my amazing success at sight-reading.)

    In the 1970’s at least, Gerald Webster delighted in taking a Morse-tapered reamer to all of his student’s receivers to lessen the gap (including the prototype Monette leadpipe I bought—arrrrrrgh!).

    I believe the mouthpiece gap can be perfect (rare), ok (almost most of the time when stock) or bad (also rare). If there is no gap, then any discrepancy of diameter between the end of the mouthpiece and beginning of the leadpipe might have an effect.


    I think.



    Maybe.
     

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