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distant ringing piezo sound...

Discussion in 'Amps, Mics & Pickups [DB]' started by shwashwa, Jun 22, 2004.

  1. shwashwa


    Aug 30, 2003
    on some of the piezos i've had over the years, and on one i currently own i get a kind of distant ringing tone that i think is common with these things. anyone know what i'm talking about? does anyone have a tip as to how to get rid of that?
  2. jcbassomatic

    jcbassomatic Supporting Member

    May 7, 2003
    Raleigh, NC, USA
    Not sure if we're talking about the same problem, but my underwood picks up the high pitch vibration of the string afterlength (string between the bridge and tailpiece). When I use my underwood, I dampen the afterlength at the tailpeice with some thick black felt. Since switching to a pickup the world pickup, I don't seem to have this problem...
  3. shwashwa


    Aug 30, 2003
    i'm also experiencing this slightly with my putw... i'm not sure why. i have a very big bass and i'm wondering if the top is just too resonant and keeps vibrating after i dampen the strings?

  4. Would you mind posting your assesment of the putw in that thread? There doesn't seem to be that many people using them, since they are relatively new(?) and I'm looking for more reactions.

  5. shwashwa


    Aug 30, 2003
    i think it's just ok... i do get some feedback with it, and they claim to be pretty feedback resistant. i also get a kind of hollow ringing tone from it. ( i have a very nice bass too.) i like the bass mex better on this bass, but every bass is different. i'm not sure if the top of my bass is so big and resonant that it's vibrating just like a string would and maybe it's giving off a pitch...

  6. mje


    Aug 1, 2002
    Southeast Michigan
    "Ringing" is a good description of what's going on; in fact, that's the term used in industry to describe undamped oscillation in piezoelectric transducers. The best way to surpress it is with proper termination of the load at the preamp. That is, you want to match the impedance of the preamp to that of the pickup. The problem is that a lot of the better preamps have very high impedance inputs that don't provide any damping at all.

    Ideally a preamp should allow you to tweak the load resistence and perhaps some reactive values as well (capacitance and inductance) to get a flat response that tapers off high enough to give you a full frequency response while providing sufficient damping.
  7. Chris Fitzgerald

    Chris Fitzgerald Student of Life Staff Member Administrator

    Oct 19, 2000
    Louisville, KY

    Wow. Would you mind posting a "For Dummies" version of this? I think if we could compile a chart of pickup impedances and common preamp impedances (did I say that right?), we might be able to save a lot of people a lot of headaches when buying. Either that, or - dummy that I am when it comes to these matters - I completely read your post wrong. :)
  8. Bruce Lindfield

    Bruce Lindfield Unprofessional TalkBass Contributor Gold Supporting Member

    I've played a few basses with piezos - like my EUB - and I've found that they do emphasise finger noise - so now I always have my nails very short, as I know that something like the nails on my thumbs, cause irritating noises, when they brush any string not being played.

    But apart from that, they have been very quiet when "untouched" ...:confused: