Microphonic Pickup. Myth or real?

Discussion in 'Pickups & Electronics [BG]' started by LT131, Dec 8, 2016.

  1. LT131


    Jan 25, 2015
    Deep South
    I have always heard about pickups going "Microphonic."

    On my Precision if I tap the bass pickup there's no noise but, if I tap the treble side you can clearly hear the tap. Is this a bad thing?
  2. Toptube


    Feb 9, 2009
    Its not a myth.

    And its only bad if it affects your tone in a negative way. See: unwanted feedback or picking up noise from other band members. Things like that. It could presumably also exacerbate the audibility of unwanted issues such as fret noise.
    40Hz likes this.
  3. LT131


    Jan 25, 2015
    Deep South
    Thanks for the reply. Can't really say that it hurts anything. It's just kind of annoying knowing it's there!
  4. 96tbird

    96tbird PLEASE STAND BY

    I've had A REAL microphonic pickup that SQUEALED. I wax potted it and it was fine.

    Never met any pickup that didn't make noise when tapped though. Any small disturbance in the magnetic field is supposed to yield sound.
    Dominic DeCosa likes this.
  5. Crater


    Oct 12, 2011
    Dallas, TX area
    I've never seen a bass with the problem personally, but it could certainly happen. I have a telecaster guitar and both pickup positions have terrible microphonic feedback, it makes this guitar useless for playing with any distortion or volume. So yes, microphonic pickups are real.
  6. Bruce Johnson

    Bruce Johnson Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    "Microphonics" is extra signal created in the circuit, caused by slight mechanical movement of internal parts of the pickup, or even the whole pickup. Tapping on the bass or loud noise in the air can cause parts to mechanically vibrate in relation to the magnetic field, which creates a signal. It can be a squeal or a thump, depending on what's making it move.

    You can get microphonics from loose wire coils inside the pickup. This is usually fixed by potting with wax or epoxy.

    Also, if the entire pickup is a little loose in its mounting, you can get the thumps when you tap on the bass. Same reason; the whole pickup does a tiny bounce within the magnetic field, creating a signal pulse. That's probably what's going on with your P-bass. The bass side pickup half is mounted tightly, but the treble side pickup half is a little springy on its mounts. Try tightening its height adjusting screws a half turn. If it feels real springy when you push down on it, check the springs/rubber tube/foam rubber block underneath.

    Mounting the pickups solidly is an important part of making a bass quiet.
    imabuddha and dralionux like this.
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