Can Multiphonics apply to guitar?

Discussion in 'Playing and Technique' started by Clifford-D, Apr 24, 2008.

  1. Clifford-D

    Clifford-D Member

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  2. Austinrocks

    Austinrocks Member

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    Yes, you create a beat note of the frequencies, the example they show is

    C4- frequency of 261 Hz
    G4- frequency of 392 Hz
    beat note freq of 653 Hz the summ of the to frequencies
    which is very close to
    E5- frequency of 659 Hz, this is equal temperment

    you also get a note if you subtract the frequencies,

    G4- frequency of 392 Hz
    C4- frequency of 261 Hz
    difference freq of 131 Hz which is C3


    The thread shows playing an C and G and getting a C bass and high E which is what the calculations show as well,
    its kind of hard to know the frequencies, I have an excel sheet that I use with all the frequencies.

    This is why certain temperments work better than others

    You also have a beat note when your tuning to another instrument or relative tuning on a guitar, while you out of tune, when your in tune the beat note goes away.
     
  3. 7/4

    7/4 Member

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  4. JonR

    JonR Member

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    I think the short answer is no.
    In theory it should be possible, but it would be a lot harder than on a wind instrument (as explained in that article).
    Wind instruments like horns have purer timbres than string instruments, so multiphonics are more possible.

    It would be worth doing some experiments, but I suspect you would need alot of compression/sustain, maybe distortion, to maximise the overtones.

    I've certainly never been able to hear undertones (difference frequencies), although they do exist.
    Eg, if you play a C# and E together:

    -12-
    -14-
    ----
    ----
    ----
    ----

    - you should hear a note equivalent to the open A string (make sure you mute the A so it doesn't vibrate in sympathy).
    This is is because the difference between those two frequencies is A - just about. Tune the C# 14 cents flat, and it should be easier. (The E also needs to be 2 cents sharp, but that may be less significant.)
    The C# should then be 550, and the E 660; the difference being 110, or low A, created by the "interference" between 550 and 660. (The same phenomenon as hearing beats when you tune two close notes to unison. The beats are just a frequency that is too slow to be heard as a pitched note.)
    Of course, the C# and E have their own overtones which may confuse the issue - adding many other potential difference tones and multiphonics. (This would be why a pure tuning is important.)

    I imagine a synthesizer would be an invaluable experimental tool for this! ;)
     
  5. gennation

    gennation Member

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    I wonder if Stockhausen experimented with this stuff. If I recall right he would take beats and speed them up until they became frequencies, ala notes. Then he'd take many of these and splice them together to make music. The advent of electronic music.
     
  6. kludge

    kludge The droid you're looking for

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    I'm hooked on multiphonics. :p

    Close intervals + distortion = "multiphonics".
     
  7. 7/4

    7/4 Member

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    The Ring Modulator is one way of doing this. Worked for Stockhausen.

    Worked for Jeff Beck and John McLaughlin.

    It can work for you too.
     
  8. Austinrocks

    Austinrocks Member

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    Actually I hear multiphonics all the time when I relative tune my guitar, that beat frequency as two out of tunes notes are played, when the guitar is in tune the beat frequency goes away, that I how I tuned a guitar for the longest time, probably don't notice them with tuners.
     
  9. JonR

    JonR Member

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    Thanks for the clarification, henry!
    (Gee, you're so intelligent for a horse... ;) )
     
  10. jzilla

    jzilla Member

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    great thread!

    thanks for the info henry!
    -j
     
  11. Clifford-D

    Clifford-D Member

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    Ok, sometimes when I play with distortion and sustain, as I bend a note upward,,
    I've heard a "sympathetic" note pitch downward, sort of like a ring mod.
    not of my doing.
    What is that "bonus" note? Is it microphonic

    My understanding that two tones come together and sum to another third frequency or tone.
    It can be seen on a Peterson strobe. But I haven't done it for myself yet.
     
  12. 7/4

    7/4 Member

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    Sum and difference tones.
     
  13. Clifford-D

    Clifford-D Member

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    Can you explain
    how it works
    :)
     
  14. Austinrocks

    Austinrocks Member

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    in an amplifier you have a term called the third order Intermodulation Distortion, when two signals are present, other frequencies are generated, its very common measurement of the distortion or linearity of an amplifer, the third order terms are

    flow= 2f1 - f2
    fhigh= 2f2 - f1

    where f1 is the lower frequency of the generator
    f2 is the higher frequency of the generator
    flow is the signal created by the amp below f1
    fhigh is the signal created be the amp above f2

    for the C4 and G4 played the amp will create the frequencies

    Flow = 2 * 261 - 392 = 130 Hz which is a C3 tone
    Fhigh= 2 * 392 - 261 = 523 Hz which is a C5 tone

    the higher the distortion level the larger the components of Flow and Fhigh will be.


    if you want to read more on the subject

    http://www.downeastmicrowave.com/PDF/IP3.PDF
     
  15. Austinrocks

    Austinrocks Member

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    Everything is In your head when it comes to music, the notes are just frequencies that are perseived by the body and the ears, and processed by the brain, the brain processes signals in different ways, especially at low frequencies a drum beat at 1Hz is not preceived as a frequency but as a beat, the fact that music creates emotion is in the brain, not in the notes.

    As I said I when I tune a guitar relative tuning where I am playing the same note on both strings to tune it I hear a beat frequency that changes and gets lower and lower as the two strings are are closer in tune, and gets higher and higher when the strings go out of tune, the absence of this beat frequency is how I know the guitar is tuned.

    the multiphonic difference frequency explains this pheonomon, if you want to say its only horns that can do this or whatever, its still something that I perceive when using relative tuning or tuning to a reference pitch like a pitch fork, since most guitarist use tuners now they probably wont see this pheonomon
     
  16. Austinrocks

    Austinrocks Member

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    man that would be nice if it where that easy, maybe relative tuning is the wrong term, reference tuning where I am using one strings note to tune another string, E string A to tune the open A string, and the A string D to tune the open D. If the intonation is correct the frequencies should be the same, if the intonation is not right you really should have that fixed.

    My term for it has always been beat frequency, but the multiphonic seems to explain what is happening, if you want to to defined as single tone instruments, so be it you are the horse.
     
  17. jzilla

    jzilla Member

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    aren't there techniques for creating multiphonics on bowed instruments (ie extreme sul pont., behind the bridge bowing, extreme forte, etc.)? afaik those techniques are considered to produce multiphonics.

    thanks for clarifying the difference between combined tones and multiphonics. very well explained.

    -j

    ps are you familiar with the extended vocal work of trevor wishart? in his book 'on sonic art' he explains techniques for producing several different kinds of vocal multiphonics including, but not limited to, subharmonics (ala the tuvan techniques). great stuff...
     
  18. Austinrocks

    Austinrocks Member

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    Henry you must play between the frets, where the pitch is raised a few cents, thus you have to tune off some to compensate, I play on the fret, which gets me the right pitch. I also play Cello, sounds like you don't care for us, scratching screeching, and I have noticed I can more notes on or under the bridge, but as you said only voice and horns can create multiphonics, and not stringed instruments. looks to me that when multiple tones occur they produce more tones, I know amps do produce more frequencies when distorted, and this is something I have measured many times. Never had a spectrum analysiser that would go low enough to measure audio at work.
     

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