Bb to C measurements

Discussion in 'Trumpet Discussion' started by BrassBandMajor, Dec 31, 2015.

  1. BrassBandMajor

    BrassBandMajor Fortissimo User

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    In a while after restoring my rotary cornet and my holton cornet I would like to have a c trumpet just for fun. I plan to buy a Olds Ambassador and convert one for fun like a project. Could anyone supply me their measurements or any kind of measurement? There is a youtube tutorial might follow that.
     
  2. stumac

    stumac Fortissimo User

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    When you are ready to do, I can send you the measurements.

    Regards, Stuart.
     
  3. BrassBandMajor

    BrassBandMajor Fortissimo User

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    Thank you
     
  4. rowuk

    rowuk Moderator Staff Member

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    Try a C cornet for fun! That could even be a Pro horn. I suspect less cost, less intonation issues and a lot more fun playing it! A C flugel would also be awesome as a project.
     
  5. BrassBandMajor

    BrassBandMajor Fortissimo User

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    Hmmm.... thanks for the recommendation.
     
  6. trumpetsplus

    trumpetsplus Fortissimo User

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    An understanding of the physics is pretty handy:
    Velocity = frequency x wavelength
    Equal temperament sets the frequency of a half step rise as frequency 1 x 12th root of 2

    You can easily get the measurements, the art is to know where to shorten. Virtually every C trumpet on the market is a shortened Bb. You can identify the ones that are not by their having a shorter overall silhouette; basically bell rim to bell crook less than 19".

    An Ambassador trumpet converted well will make a much nicer C than it was a Bb especially if you throw away the stifling bell/valve casing/lead pipe braces and use regular ones hanging off the 2nd valve casing.

    I do not recommend C flugel conversions. I have done some at customers' insistence. The problem with these is that there is no cylindrical tubing to shorten, so you end up having to match 2 different bore sizes at some point.

    Here is one I did:
    [​IMG]
     
  7. trumpetsplus

    trumpetsplus Fortissimo User

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    Here is an Ambassador I did.

    [​IMG]
     
  8. rowuk

    rowuk Moderator Staff Member

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    I have always ben told that C trumpets were built this way to keep the bell at the same distance as a Bb from your ear. That was supposed to make switching easier. My experience with pistons has always been that the longer the leadpipe, the better potential for optimal intonation (with the exception of rotaries that have a completely different balance of tapered to cylindrical tuning). Dave Monette however proved to me that there is nothing wrong with a short leadpipe.

     
  9. trumpetsplus

    trumpetsplus Fortissimo User

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    Here is a prototype I have just finished - a C trumpet with an ascending quarter tone valve
    [​IMG]
    [​IMG]

    You will notice that the bell is shorter than the standard C trumpet on this model.
     

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