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what frequencies are affected by tone knobs on a guitar amp?

Discussion in 'Guitars' started by Noratacka, Dec 19, 2007.

  1. Noratacka

    Noratacka Guest

    Are there any generalizations one can make regarding the frequency ranges affected by the tone knobs on a guitar amp?

    i.e. the range of bass, mid, treble, and presence

    i.e. bass (80-300hz) *not sure if this is correct

    I realize that all amps are different...but, I was hoping someone who is experienced can give a frequency breakdown of the general frequency ranges the bass, mid, treble, and presence knobs are affecting.

    thanks so much for your help
  2. hueseph

    hueseph Distinguished Member

    Oct 31, 2005
    Vancouver, BC, Canada
    Why? Why would it matter? You're not going to get surgical with your tone pots on the amp. Tweak them till it sounds good. If you need better control get an eq pedal or rack. If you really need that info it might be best to go to "the horses mouth" so to speak. Call tech support at Marshall or Fender or whatever amp it is you are using or plan to use.
  3. Noratacka

    Noratacka Guest

    Thank you for your response.
    I wanted to know because I am somewhat of a beginner and it would really help me as a general guide. I realize that the "ear" should be the final judge, but a general guide would help in training.
  4. Take Hueseph's suggestion foremost, especially given that your instrument, speakers, and other variables will affect perceived tonality.

    As a gross generalization, though, it might go something like this:

    Bass: ~70 - 200 Hz
    Mid: 250 Hz - 1 KHz (1 KHz = 1,000 Hz)
    --If your mids are broken up: Low Mids: 250 - 450 Hz; High Mids: 450 Hz - 1 KHz
    Treble: 1.5 - 4 KHz
    Presence: 3 - ~7 KHz

    Although these values are estimates, they will almost surely be in this order regarding tonal control (from low to high).
  5. And, incidentally, it really is much better attune your ears to what you think is a "good" guitar sound and follow this as a map to EQ'ing your amps. My buddy Johnny, who knows comparatively less about the audio stuff I've prided myself in learning, can instantly pull great tones out of amps I've sworn were junk.
  6. Noratacka

    Noratacka Guest

    Thank you very much for your detailed answer, Patrick. I guess part of the reason for my question was to get a coherent nomenclature for frequency ranges. I don't have many friends who can talk tech, so I am trying to find some terms to define what my ears hear.

    My confusion comes from the fact that many "books" define midrange as broadly as 800-5k . I know a guitar cabinet doesn't produce much over 5k...so it seems to me that a guitar amp wouldn't really produce any highs or treble technically...but all midrange.

    so that leads me to ask... is treble/highs a relative term?

    Thank you again...and my apologies for this being such a newbie question.
  7. Link555

    Link555 Distinguished Member

    Mar 31, 2007
    North Vancouver

    Check this out, it deals with various EQ from popular brands. Keep in mind the speaker, cabinet and amp circuit all affect frequency response as well.
  8. The term "midrange" is both relative and subjective. These books seem to be talking about the whole of the audible frequency spectrum, which is 20 Hz to 20 KHz (or 20,000 Hz). More realistically I, a layperson, would define this midrange as being ~400 Hz to 4 KHz, and in this sense, an electric guitar is almost entirely a midrange instrument.

    With this said, let's look at an electric guitar: the tones (notes) it can produce, in standard tuning, are 82 Hz to just over 1,000 Hz. Its overtones and harmonics (tonality, i.e. highs, mids, and lows), though, extend far beyond this. But due to pickups on a guitar and circuitry and speakers of the amp, anything coming out of that box dramatically drops off after around 5 KHz --ergo, anything above, say, 1.5 KHz is usually going to be considered ia guitar's high end. And an amp's tone controls work thusly.

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