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Help with Upright Bass Feedback?

Discussion in 'Rockabilly [DB]' started by will_b_vinson14, Feb 11, 2021.

  1. Howdy y'all,
    I use a Shadow SH-RB-Pro pickup on my bass, then into an HPF-Pre, and finally, my amp is an Ampeg BA115HP. I can't turn it up all the way without getting that horrendous low-end, rumbly feedback. The Shadow is equipped with settings that are "cheat codes" in a sense (as Colin from The Brains puts it on his YouTube channel), which are very helpful, but don't quite get the job done. I also got the HPF-Pre low cut/high pass filter for battling feedback after seeing it on the Discover Double Bass YouTube channel. I've considered adding a second soundpost, but I'm hesitant since I play acoustically a lot. I'm also not as big a fan of tape or foam blocking the f-holes, only because I'm not a huge fan of the look. I've talked quite a bit through Instagram with Gollo Garcia from The Delta Bombers, and he suggested an EQ pedal where I can cut out/add highs/lows. I've wondered how the heck Jimbo from RHH doesn't seem to have feedback problems, but I think a lot of it has to do with the way Jason Burns builds the Blast Cult basses. Any help/advice/tips would be greatly appreciated. Thanks so much.
    ---Will V.
    Keith Rawlings likes this.
  2. Kro

    Kro Supporting Member

    May 7, 2003
    New Jersey
    Do you know where your HPF is set?
  3. I usually have it set between 35 and 80 Hz, but more so towards 35. The phase switch is switched to positive.
  4. Kro

    Kro Supporting Member

    May 7, 2003
    New Jersey
    Does having it set around 80Hz make for any improvement over lower settings?
  5. Dr. Love

    Dr. Love

    Nov 5, 2008
    Lubbock, TX
    Feedback is a constantly moving target, so there’s no “one size fits all” solution. I’ve had gigs where there were no problems and others where nothing helped. The biggest factors are overall volume, bass position relative to the sound sources, and resonance of the instrument.

    Here’s what I usually do: keep myself between the amp or monitor as much as possible or stand to the side of it, then I put a block of packing foam cut to fit behind the tailpiece to deaden those resonances, then adjust the HPF as needed. This solves 90% of situations. If I still have issues, I have f hole covers I made myself. I used the craft foam sheets that are about 1/4 inch thick. I traced the f hole and cut one layer to fit inside the f hole, then one slightly bigger, then glued the layers together so it pops in and out easily and looks much better than tape or blocks of foam. I rarely have to use them though.

    Then some gigs nothing works, usually it’s where someone is running sound who thinks the bass drum and toms should be at a nausea inducing level. Only a magnetic pickup works in those situations.
    Last edited: Feb 11, 2021
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  6. It's more so just a tone thing, but I don't really like to go past 80 Hz since that's where it starts to get a pretty mid-rangey sound, and with that comes more feedback.
    Keith Rawlings likes this.
  7. bassburner

    bassburner Supporting Member

    Dec 8, 2008
    I've played around with a lot of techniques to getting rid of feedback on my upright and the one sure fire fix is a notch filter. I have a Felix but I'm sure there's a standalone option.
    Wasnex and will_b_vinson14 like this.
  8. bassburner

    bassburner Supporting Member

    Dec 8, 2008
    Also, what's Colin's channel? I'd like to check that out.
  9. DukeCC


    Nov 4, 2016
    I second Dr. Love's analysis, experience, and advice.

    I made f-hole covers using flip-flop rubber, but I'm sure the foam works at least nearly as well, and would be easier to install, meaning you could use only when/as needed.
    will_b_vinson14 likes this.
  10. bherman

    bherman Supporting Member

    Apr 30, 2009
    Grand Junction, CO
    In reading your OP, my focus is on your statement, "I can't turn it up all the way...". If you want to be able to play really loud then you either need to take measures to reduce the resonance of the bass (ie closeoff the f holes) or consider switching to a magnetic pickup. I used to use a Krivo pickup and it allowed me to get pretty damn loud before there were any signs of feedback. You do have to be careful about the type of strings that you use - check out the Golihur Music website for information about this. Other thought that I have is maybe cut down on your amp volume a bit a run your bass into the PA - just a little, enough so that your amp doesn't have to carry the whole weight. Jussstby virtue of their design, its hard to get DB loud from an amp without feedback issues. The Krivo will get you there, though.
  11. Thanks for the help, I'll definitely check out Golihur's website.
  12. Keith Rawlings

    Keith Rawlings

    Aug 3, 2019
    Try messing around and EQ’ing out the problematic frequencies. I found that a lot of the extreme low frequencies tend to make my bass feedback more. I tweaked the settings on my K&K Rockabilly preamp to take these out then I make sure to always have the HPF engaged on my AI Clarus amp (I run the Clarus with all settings at “high noon” then back them off or bump them up on the preamp). I find that upper mids and middle set treble frequencies don’t feedback as much and sound best with my Kay. I’m using the Vic’s Model C stereo pickup into the Clarus. I cringe when I think about covering up my F-holes. Years ago I played shows with other bands who did outrageous things to avoid feedback. One guy filled his Englehart bass with strips of mattress foam! It sounded like dog but it didn’t feedback. Other players would tape up the F-holes and I just feel like you lose all semblance of what it means to have an acoustic instrument.

    Have you tried using a 8”, 10” or a 12” speaker? I’ve always had major feedback issues with 15”s and above. They just don’t work with upright bass frequencies and slapping seems to make it worse. That’s been my experience. 10”s seem to be ideal for the sound I like and I find that most of my double bass playing compatriots agree.
  13. Wasnex


    Dec 25, 2011
    I played professionally for about 25 years and never used an HPF. I am not saying an HPF would not be beneficial, but in my experience, upright doesn't typically have feedback problems at such low frequencies unless the PA is really hyping the subs. I have had problems with frequencies below 100hz maybe twice and the problem was with the subs.

    I do think F-hole covers or plugs could be beneficial as well, especially for extreme volumes like a rockabilly band. Never used them with an upright, but I have seen how beneficial a sound hole plug can be with acoustic guitar, so :thumbsup:. I believe there are companies that make foam plugs, but I don't know if they do custom plugs.

    The tricks I Use:
    #1. Using an amp with fairly flat response is a good start. At the very least you don't want an amp that emphasisez the low mids, because the low mids tends to be a problematic frequency range for upright bass.
    #2. I typically elevate my amp to about waist level. The idea is to get the cab closer to my ears and further from the body of the bass. If you put less energy into the bass, you weaken the feedback loop. Some people really hate this approach, and it may be best to do this when the PA is carrying the bass to the audience.
    #3. As others have mentioned corrective EQ, and specifically notch filtering is extremely important. You need to consider the bass, pickup, amp, and speaker a system. There is a feedback loop that exists between the speaker and the amp and as you increase the volume, this feedback loop gets stronger and tends to exaggerate resonances in the system response. You use the corrective EQ to compensate for this problem.
    There are two types of corrective EQ that you can consider. The first is narrow band or notch filtering. As you turn up the gain the bass will tend to feedback as specific frequencies. Ideally you want to put a fairly deep narrow-band notch at this frequency to kill the freedback. In my experience you can kill 4-5 frequencies and and after you typically hit the point of diminishing returns where it starts to kill the sound.

    I have used 31-band graphic EQs for nothing and also fully parametric EQs. Empress used to make a pedal that would be a good choice for this called the ParaEQ. It has three bands of EQ with variable frequency centers and the bandwidth has a 3-way toggle that can be set to wide, medium, or narrow bandwidth.

    The second type of corrective EQ you may use is broadband. Sometimes you get to a point where the volume cause the strings to want to pump or ring across a certain range of the instrument. In other when you pluck the strings, they bloom and ring continuously instead of decaying naturally, so you have to mute them with your hands. A broadband band dip across this range of the instrument can help restore more of an even response. Also you experience a situation where you have several adjacent frequencies that want to ring instead of one clearly defined frequency. This is another situation where you would use a broad band dip. The trick is that when you use a broad band dip you only cut a little, and when you use a notch you can cut really deep.
    One other factor I should mention is the bass itself and the choice of pickups. The last bass I played professionally would be called a "fine instrument"as it would have been at home in a world-class orchestral bass section. It did not amplify particularly well because it was designed to be very resonant so it would be a canon acoustically. I was able to amplify the bass successfully, but it always got sort of boxy pizz sound through the amp.

    Then again it had one of the original Realist pickups, which was probably not a great choice for that instrument. Using a bridge mounted transducer to sense less of the body and more of the strings would probably have provided much better results through the amp. For the record I used the Realist on 3-4 basses before this one and always got a decent sound.

    My suggestion is to hunt down a use Empress ParaEq and run that after your Shadow preamp. Try to get your basic sound with the amp's EQ, and then use the ParaEQ as a utitily EQ. In other words use the ParaEQ to correct problems.
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  14. AlBass


    Aug 19, 2018
    What's the best make of flip flops for traditional rockabilly? ;)
    unbrokenchain and Keith Rawlings like this.
  15. This thread may be useful to you.

    Stopping Feedback in LOUD Settings

    and specifically this post from Uncletoad.

    Stopping Feedback in LOUD Settings

    Another tip is your playing technique. Amplified bass works better with left hand playing on the finger pads instead of the finger tips. Use your flat left hand to mute open unused strings and your right hand also mutes unused strings. Everything except the one note you are playing at that instant needs to me muted by you using player techniques. (A big difference from acoustic only playing where resonance is sought after.)
    Last edited: Mar 20, 2021
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  16. Keith Rawlings

    Keith Rawlings

    Aug 3, 2019
    Telics or Oofos. Orthopedic flip flops for the arthritic slappers!
    AlBass likes this.
  17. AlBass


    Aug 19, 2018
    Keith Rawlings likes this.
  18. unbrokenchain

    unbrokenchain Supporting Member

    Jun 8, 2011
    Black Mountain, NC
    I’m not a dedicated RB guy, but here’s what I got - second the comment about getting your amp/monitor positioned so that it doesn’t interface your instrument, angle relative to floor is key. Most pro loud bands actually don’t have crazy loud stage sound (um longevity concerns!), the volume comes from FOH. In fact, loud stage amps are kind of the sound person’s peeve generally, speaking from experience as a sound dude here... Personally as a player I like to have mostly high end info coming through my amp/monitor, makes me focus more on playing clean and in tune, let the boom come through out front.

    I’ll never forget watching the Sam Bush band from side stage and being able to hear them talk to each other in a regular speaking voice, but out front it was absolutely deafening! Mandolins feedback too I guess :laugh: But really, careful with those ears, they’re awful handy for music..;)
    AlBass and longfinger like this.
  19. unbrokenchain

    unbrokenchain Supporting Member

    Jun 8, 2011
    Black Mountain, NC
    Also, a tennis ball or other goofy giant end pin stopper can help with feedback when subs are below the stage.
  20. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

    May 7, 2021

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