Measurements of trumpet bore along entire length

Discussion in 'Trumpet Discussion' started by gordonfurr1, Jan 20, 2015.

  1. gordonfurr1

    gordonfurr1 Forte User

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    I recall seeing a list of internal bore diameters taken along the entire length of a (I think some nice vintage Olds) trumpet...measurements taken about every inch along the instrument. For some reason, I just cannot seem to find this information now. Does anybody recall this? I checked over the more well-known Olds sites and didn't spot it.
    The reason want such?
    Want to start rough CAD design of three-section molded plastic super-micro-pocket trumpet with integral porting.
     
  2. rowuk

    rowuk Moderator Staff Member

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    I never saw this, although there must be some research on this. I can tell you that your development will not be helped one bit by this info. Many years ago, someone built a rotary trumpet using Bach Strad parts and a rotary valve section. It played completely different due to the bends and bracing being elsewhere. It would be a bigger help to simply measure a good working pocket trumpet and then experiment with leadpipes. That being said, plastic resonates differently than metal, so probably NOTHING on previous developments will help.

    Goog luck. If I was going to do something like this, I would email Richard Smith at Smith-Watkins and ask him for this info. I don't know him personally, but he is the real "rocket scientist" of trumpet artisans and his horns sound good, have great intonation and response too. Anyresponse from him probably would be worth gold!
     
  3. Sethoflagos

    Sethoflagos Utimate User

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  4. gordonfurr1

    gordonfurr1 Forte User

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    FASCINATING. HMMMM. "MOST of the sound reflects back except for what escapes the bell..which you hear..." (paraphrased). I knew about reversions from sports-car engine exhaust header design, but did not realize that MOST of the acoustic energy reflected back towards the player inside the bore on reversion. I expected something like maybe 5-10% as a hunch. This makes me desperately want to tinker with devices that modify the reversion and see what effects can easily be wrought. I have already been wondering about an extended rim plate (perhaps a rigidly attached plate made of a tonewood such as walnut) that fits around the existing bell bead, maybe even curving backward more than perpendicular to the bore axis of the bell. This might have some interesting effect on the reversion...and would be removeble...(probably a good idea since more than likely the effect would be detrimental). So....maybe if I can find myself a small wood lathe I can concoct such a piece and satisfy some personal speculation.
    I would imagine something like a pocket trumpet would be a really extreme example of shape that would create a myriad of internal reflections. Perhaps if I made the shape more consistently rounded instead of straightaway/curve/straightaway/curve there might be less obvious reflections...maybe.

    When I first saw the article, I thought it was one I had already come across based on his cover page...but this was different and also (like the one I had already seen) extremely interesting.
     
  5. gordonfurr1

    gordonfurr1 Forte User

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    I have considered turning an elastic piece (maybe clay) representing the inner bore of a trumpet...and folding it creatively into as tight a wrap as possible (without any of the tubes touching) to form the negative of a mold...then cast resin around the clay to form a positive...I know the clay I use for sculpting shrinks about 10% when air-drying, so I should get fairly close for what I am shooting...(shooting from the hip big-time, aren't I?). I realize the little pocket trumpet I would create would most likely be nothing more than a toy, but actually a "toy" is what I am seeking. Much like comparing a Martin Backpacker guitar to a D-28...but even a lowly Backpacker has its place...and that is quite a fun place.
     
  6. gordonfurr1

    gordonfurr1 Forte User

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    How consistent is the wall thickness throughout the length of a typical trumpet?
    Aside from doubled walls at slides, I could simply mic the outside dimension along the length, and subtract double the wall thickness...four times at slides...and arrive at a pretty close section diameter map off a trumpet..
    I suspect also that the cross section needn't be round, either..that a rectangular section of the same area would work just as well...though changing from round to rectangular might cause reversion reflections...and difficulty at valve ports and slides...
    Now, did you ever wonder how Adolphe Sax arrived at the port locations and sizes for his keyed instruments?
    Wouldn't it be cool to make the uber- mini pocket trumpet not even have valves, but be so designed that you could finger it ocarina fashion? Since the ports would need to be different sizes, and all CLOSED until needing to be opened up from the far end (the opposite a clarinet) I am supposing that simple open holes would NOT work, we don't have enough fingers...that I would have to make spring loaded keys of some sort...lot oft hinking and scratching to be done here.
    THAT would make for a neat, novel, but functional toy..and fit my cost parameter.
    How DID Adolphe do it?

    http://s853.photobucket.com/user/gordonfurr1/media/keyed bugle/CollinsKelloggtst.jpg.html?sort=3&o=0


    So now, I am imagining something along the lines of an ocarina but having an orifice shaped like the lip of a mouthpiece at one end, and curled inner pathway coiled so as to land the finger openings where they might be manageable without using pads and keys and levers...just finger openings...and terminating in a small bell that maybe could actually screw in or out a little bit to provide some crude measure of tuneability. Something that is REALLLLLY a pocket trumpet..that could legitimately be slid into a man's pant's pocket and be carried without concern of damage.

    An (ophicleide)

    It's a tall order, but wouldn't it be cool to make something that actually COULD be played and produce something reasonably recognized as "music" all in three or four part molded resin piece. I am researching now how Adolphe Sax actually DID locate his opening locations...maybe I can just find a keyed bugle in Bflat or C and measure to the opening centers along the center axis. Thoughts?

    Here is a recording of such a keyed bugle...sounds amazingly "cornetish" to me...and probably DID have the typical deep vee cup and flat rim mouthpiece...
    It IS a flugel/bugle bore so that adds dramatically to the softness of the sound...though having a deep vee mouthpiece might actually help disguise the varying softness of the various notes due to differing amounts of pads being exposed.

    http://youtu.be/uECYY6b_3R8

    When a kid, I learned to play a fairly reasonable chromatic scale on my conch shell (I chopped the end off of as large conch shell I had picked up at Ocracoke off the coast of North Carolina)...much like is done with a natural horn, I was able to cup my hand in the bell and quickly learned to play songs while moving my hand in and out of the "bell" (shell flare). It actually came quickly, though cupping muted the sound a bit. Perhaps I could just do a similar thing with this pocket horn..have a few openings where convenient for the player's right fingers, then use the player's left hand to effect harmonic shifts in the bell. That would be, by far, the CHEAPEST and EASIEST way to make such a tiny trumpet.../
     
  7. gordonfurr1

    gordonfurr1 Forte User

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  8. rowuk

    rowuk Moderator Staff Member

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    This is why I post so much on relaxing and letting the horn do the work. The standing wave is the secret........

     
  9. gordonfurr1

    gordonfurr1 Forte User

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    Going back to the design of racing car exhaust sytems (which probably bear more resemblance to trumpet acoustics than most would realize) we would anticipate what RPM our horsepower peak would occur, then "TUNE" the exhaust length to time that reflecting reversion wave so it would get back to the valve exhaust port at exactly the beginning of the exhaust valve opening...then it would reflect AGAIN (reverse) into the direction we were wanting the next exhaling of exhaust gas to go..and the effect of the reversion would be somewhat like an additional impulse...a boost without a turbo (if you will) to speed even more the exhaust gas exit. This would increase power, and would also make the exhaust note have a purer tone when it was properly set up. It would then "wail".
    I suspect...that similar reversions..though the impulses are very scattered at the dizzying array of notes (and therefore pipe length) a player experiences on a trumpet...may play an important role in the "stuffiness" one may feel in a trumpet. I think probably even more than the bore size. If a player is experiencing reversions coming back at his lips when the pulse should already be on its way downstream it WOULD SEEM TO BE RESISTANCE...and indeed it WOULD be. Think about it, many medium and even slightly smaller bore trumpets can feel "open" and SEEM like they would be larger bore instruments. Of course, mouthpiece design, horn architecture (to some extent), bracing, wall thickness, and probably a million other things contribute to that feel, but IF MOST OF THE ENERGY A HORN PRODUCES REVERSES IN REVERSION AT THE BELL AND FLOWS BACKWARDS TOWARD THE PLAYER'S LIPS, REVERSION DESIGN AND TIMING HAS GOT TO BE A MAJOR INFLUENCE ON THE FEELING OF STUFFINESS OR OPENNESS OF AN INSTRUMENT'S BLOW.
    Thoughts?
     
  10. Cornyandy

    Cornyandy Fortissimo User

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    My head hurts, but this is interesting
     

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