Trumpet Physics

Discussion in 'Trumpet Discussion' started by Tootsall, Jan 8, 2004.

  1. Tootsall

    Tootsall Fortissimo User

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    Yee HAW!
    OK...as an engineer I'll admit that I tend to get a little "geeky" about the physics of things from time to time. Anyway...I found a reference to this website "elsewhere" and I thought I'd share it here. Be happy to discuss the contents with those who have read it and "understand" (or even "think" they understand) what's being said.

    http://joeleymard.free.fr/Benade/Trumpet73/Trumpet73.htm

    At the same time, here is a second site that provides some basic information on the creation and sustenance of sound waves within brass tubing. You might be wise to read this one through before the one mentioned above:

    http://hyperphysics.phy-astr.gsu.edu/hbase/music/brass.html#c1

    One last site which perhaps says similar things in different words is that of Nick Drozdoff (whom I've made mention of before). Nick is a physics teacher who spent a stint playing with the MF band so he's got an "eyeball" on the situation from two sides at once. Check out:

    http://www.geocities.com/Vienna/3941/

    So if you've got trouble falling asleep at night...print these sites up and use them for bed-time reading! :D
     
  2. Terry Layzell

    Terry Layzell Pianissimo User

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    I find this interesting but the graph showing response doesn't show the frequencies of those responses or better still the notes which they produce. What does "6th harmonic of harmonic 2" mean in terms of what notes they represent?
     
  3. rowuk

    rowuk Moderator Staff Member

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    There is a big problem when we use the word Harmonic when we mean Partial. What they meant was the 6th harmonic (6 wavelengths in the length of the trumpet) of the second partial (low c when no valves are depressed).

    The problem is that the harmonics (overtones) that determine the color of our instrument all happen at the same time. It really makes no sense to deal with them individually.
     
  4. Terry Layzell

    Terry Layzell Pianissimo User

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    Doesn't it? Doesn't that depend on what aspect you are talking about? For example if it's tone colour versus if it's pitch of the notes versus the length of tubing in play. And why do you call low C a partial? If you're playing low C ie C4, ie middle Bb concert I'd have thought its partials were G4 the next G going up, C5, E5, G5, Bb5, C6 not the low C itself. Am I wrong?
     
    Last edited: Feb 25, 2018
  5. rowuk

    rowuk Moderator Staff Member

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    The notes that we play on the open horn are partials. Pedal C is one wavelength in the horn, one octave higher (2 wavelengths) is low c - because there are 2 wavelengths, we refer to them a partials. 3 wavelengths (3rd partial) is G in the staff. 4 is 3rd space c, 5 is 4th space e, 6 is g on top of the staff. Octaves are a doubling of frequency.

    Harmonics are also multiples of a fundemental frequency, but they occur at the same time that the fundemental is played, not as an individual tone. They are what determines the tonal color of the instrument - why for instance an oboe sounds differently than a trumpet.

    So, partials are the pitches that we play, and harmonics are the trumpet color - not the other way around.
     
    J. Jericho and adc like this.
  6. trumpetsplus

    trumpetsplus Fortissimo User

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    There are actually 3 different nomenclatures that I am aware of:
    1 Fundamental and overtones
    2 Harmonics
    3 Partials

    I learnt about the first 2 in school (admittedly in the antipodes), the 3rd one, partials, is newer to me.

    Harmonics and Partials are numbered from 1. 1 = pedal tone
    Fundamental is the pedal tone with the overtones numbered (one number less than its Harmonic or Partial twin)

    For instance, 4th space E can correctly be called the 5th Harmonic, or 5th Partial, or 4th Overtone.
     
  7. Terry Layzell

    Terry Layzell Pianissimo User

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    Thank you again Ivan. Very informative. Obliged.
     
  8. trumpetsplus

    trumpetsplus Fortissimo User

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    Unless one is playing a flute or recorder softly (these generate pretty much a pure sine wave), all musical notes consist of a fundamental frequency plus some harmonics of that frequency. Spectral analysis will show what harmonics are present and at what amplitude.

    As examples:
    Sine Wave - flute or recorder
    Sawtooth Wave - Clarinet
    Square Wave - Oboe

    The harmonics associated with a particular sound (known as Formants) tend to be static, so that it is possible to play such a high note as to not be able to distinguish what instrument is playing. Try asking a coloratura soprano to sing the word "you" on a high Eb. She will sing a note but you will have no idea what she is singing. Hmmm, is that unusual!

    So there are 2 different things being referred to using the same terms.

    A string or tube will resonate both at its fundamental frequency, and at harmonics of that frequency.
    Musical notes comprise a fundamental frequency plus various harmonics of that frequency.

    This partially addresses the question - a more fundamental understanding will come from a study of Benade and others. This is as "egg-head" as I am prepared to go.
     

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