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Acoustic Bass Feedback

Discussion in 'Amps and Cabs [BG]' started by lilcrate, Jan 10, 2014.

  1. lilcrate

    lilcrate Tortdaddy

    Sep 9, 2013
    St. Louis
    When I hook my acoustic bass up to my amp, it slowly starts building up a vibration that just gets louder and louder anytime I'm not playing. All by itself. The only way to get it to stop is to turn the volume WAY down which kind of eliminates the purpose of amplifying it. Anyone else experience this?

    Guitar is a Breedlove 4-string and amp is Tone Hammer 500.
  2. GKon

    GKon Supporting Member, Boom-Chicka-Boom

    Feb 17, 2013
    Queens, NY
    This is pretty typical with acoustic/electric basses.

    You can buy an insert that covers the sound hole, which stops this from happening when you plug in to an amp.
  3. Dmwphoto

    Dmwphoto what does this light/\ do?

    Nov 27, 2013
    Richmond va
    Why would you need volume turned up if you are not playing it?
    The suggestion above for the insert will help
  4. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    First try the sound hole cover but sometimes they do not work well enough. People resort to stuffing all sorts of things into the body. I once bought a hollow body instrument that had a bed sheet stuffed in it to prevent feedback.

    If you are using the LRBaggs under saddle pickup, I don't know if there is much that you can do. If you are using a sound hole pickup, sometimes using wax to seal the outside bottom of the case can help damped resonances that cause feedback. Other times the coil needs to be potted with wax.
  5. lilcrate

    lilcrate Tortdaddy

    Sep 9, 2013
    St. Louis
    Well there are times when a note is not being played during a song, not to mention the moment I stop to talk to my guitar player about the song we are playing.

    Literally if the volume is turned up just enough to keep up with his acoustic guitar, then I CONSTANTLY have to be muting the strings or in comes a rising vibration/noise.

    Thanks everyone else for the help. I will look into it.
  6. Dmwphoto

    Dmwphoto what does this light/\ do?

    Nov 27, 2013
    Richmond va
    I see, I thought you meant on the stand.
  7. lilcrate

    lilcrate Tortdaddy

    Sep 9, 2013
    St. Louis
    It's bad enough where my speakers would be blasting if I walked away for probably 30 seconds. It really sucks. Especially since the bass isn't that loud without an amp.
  8. Yeah try the sound hole cover that should help a little
    My acoustic/Electric has a anti-feedback switch on the built in Eq without it on it does the same thing at any volume of 2
  9. BassmanPaul

    BassmanPaul Gold Supporting Member

    Aug 25, 2007
    Toronto Ontario Canada
    If you walk away from your amp, unplug the bass or turn the volume down. Folk have been doing this since the early days of amplified acoustic instruments. You can also try to move further away from your speakers.
  10. Bassmec


    May 9, 2008
    Ipswich UK
    Proprietor Springvale Studios
    Apart from putting a bung in the sound hole the EQ section of your amp can be adjusted to avoid the resonant frequency of your bass, so just try cutting at various frequencies between 120Hz and 350Hz.:bassist:
  11. Selta


    Feb 6, 2002
    Pacific Northwet
    Total fanboi of: Fractal Audio, AudiKinesis Cabs, Dingwall basses
    If it's from the strings only - do what the ERB guys do - put a scrunchi on near the nut. When not playing, slip it over to like the 1st or 2nd fret. When you play again, slip it back over the nut. It might not stop it entirely from happening, but it should help keep it from increasing much.
  12. okcrum

    okcrum in your chest

    Oct 5, 2009
    Verde Valley, AZ
    RIP Dark Horse strings
    Try moving a step or two to either side. If you are directly in front of the amp now, this might help.
  13. sowilson


    Jul 5, 2013
    get yourself an outboard preamp with a notch filter. LR Baggs and Fishman are two that come to mind.
  14. tbirdsp

    tbirdsp Supporting Member

    Sep 18, 2012
    Omaha, NE
    I don't play an acoustic bass but I always have the strings muted when I'm not playing. I don't even think about it.
  15. Scottkarch


    Sep 11, 2012
    not standing/sitting in front of your amp will make a huge difference. Have the amp in front of your or next to you pointing out to the audience. When we play tiny pubs, I like to use a plugged in acoustic bass. It just looks like it fits better, but I have run into the same thing. I will probably look into a soundhole plug as well.. but just moving away from the amp makes a big difference.
  16. Ukiah Bass

    Ukiah Bass Supporting Member

    May 10, 2006
    Technical term for a sound hole plug ... feedback buster.
  17. Scottkarch


    Sep 11, 2012
    Interesting. I wonder how/why they work. Are they heavy and dampen the top of the bass from vibrating as easily? They don't look like they would do much. I believe they do. I just don't understand how they accomplish it.
  18. JTE


    Mar 12, 2008
    Central Illinois, USA
    Feedback is the sound from the speaker bring picked up by the instrument and being fed back to the amp. Start with true source- get a GOOD EQ, a semi parametric preferably. Find the frequencies that are causing the feedback and notch them out. Only after that resort to damping the instrument.

  19. Scottkarch


    Sep 11, 2012
    I have a 10 band pedal eq. I wonder if the bands are narrow enough to work.