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Double Bass Opinions wanted!

C

Carolinabassist

May 26, 2012
3
0
Atlanta GA, Durham NC
Disclosures
Endorsing artist: Eden amps, Clayton accessories, Westone in-ears
#1
I understand that this probably sounds nuts but it's just an idea that i wanted to float out for comment. I'd love for some guys who know way more about upright than i to tell me whether this a horrible idea or may actually work.

I'm having major feedback issues from my cheapo chinese Palatino upright. I've tried EVERYTHING from magnetic pups to EQ to stage position to putting a towel in the body and i'm always left with horrible feedback. I had the idea to fill the body about half full with a type of canned, expanding foam insulation called "great stuff". I understand that this is going to lessen the natural acoustic tone of the instrument and devalue it greatly (from the enormous $500 it's worth now) but is there any reason why this isn't worth a try? has anyone tried this before?

Last note, i spoke with my luthier and he told me if it went horribly wrong he'd remove it for me for $100. so all in all it won't be impossible to reverse.
 
#5
Sometimes covering the f-holes with tape or sticking foam cut to the shape of the holes will help.

Standing in front of the speaker will cause feedback. More mids less lows. What about speaker setup?

I have never used the Eden stuff, but I found that GK amps provide a good sound for amplified upright particularly if your trying for high volume.

It's all about trial and error with amplified upright...pickups, amps, speakers...
 
#6
Have you tried a high pass filter in you signal chain? If not, then definitely check it before filling you bass with that insulation stuffing. IME, feedback is caused by sub-sonic frequencies (that are dealt with the HPF), otherwise the low mids may sometimes be the culprit, but you appeared to have experimented with that already... In any case, I'm pretty sure you don't need that "great stuff" with a magnetic PU.
 
#9
Does it usually feed back on the same note/notes? With the Full Circle on my two basses the open D is a lot louder. And it will feed back at this frequency if I push it. WAYYY sooner than any other notes.What I use is a small parametric eq where I can "notch" out just that note. Badda bing badda boom feedback gone. I'm betting that this is the problem. My Fishman Dual Parametric has two fully parametric bands. If your feedback is just the super low notes, yes a HPF may work. But I doubt it. I never feed back in the uber low range. Magnetic pups are much less prone to feedback but if you have a hot note (resonant point) it causes a feedback loop as the sound coming from your amp excites the body of your bass. The Fishman is no longer made but if you search you can find one. TB'er Ukiah Bass uses a small parametric pedal that seems nice. Important thing is that the width being attenuated (Q) can be adjusted to a narrow notch.
Please don't fill your bass with foam!!!!!!
 
#10
Mic the bass, plus it wont smell funny from the foam, i prefer micing the instrument over a pickup, i feel that theres something sonically lost from wood to pickup, and i feel you get more by micing or no amps at all.
 
#12
DON'T DO IT!

When Great Stuff and other similar products cure, they can harden, they will dry up and release from the walls of the inside of your bass and then you'll have a thick, hard piece of debris rattling around inside your bass. I've spent a significant amount of time working with car audio and people always want to put great stuff in their car doors to isolate them better but the same thing happens to them, it dries up, then rattles around in their door. Feedback can be quite a problem, but I would really recommend trying other options.
 
#13
Carolinabassist said:
I'm having major feedback issues from my cheapo chinese Palatino upright. I've tried EVERYTHING from magnetic pups to EQ to stage position to putting a towel in the body and i'm always left with horrible feedback.
Click to expand...

Uncle Toad posted a very good set of things to try, that can help eliminate feedback.

"The more resonant and loud your instrument is the harder it will be to amplify. The best orchestral basses just don't respond well to playing amplified loud. Good sounding but quieter tighter basses will amplify loud easier. Poorly set up basses won't amplify loud well either. Any deficiencies in setup will be magnified under amplification."

"I have played ridiculously loud in small and large venues with huge rock bands using my plywood New Standard Cleveland bass with a Full Circle pickup into an AI Focus 2RIII and Euphonic Audio VL208. It manages to still sound like a string bass too."


"Several Considerations;"
1.The onstage bass volume should be low, feel the low end and presence of the bass through the PA.

2. Use the onstage system with mids and highs only as a personal monitor to stay in tune.

3.Dial in the front of house sound without any on stage sound whatsoever and then turn up your rig just enough to play in tune when everything else kicks in.

4.Try to get whatever personal monitors you use up off the floor near your ear and away from the body of the bass.
Stay well behind the main speakers and well away from the subs.
5.Keep the bass out of the floor wedges and stay as far away from any on stage speakers as you can.

6.Use the rubber stopper on the endpin and don't stick the pin directly into the floor.

7.Experiment with phase reversal on the preamp.

8. Experiment with high pass filters on the preamp. (try the fdeck preamp!)

9.Stay away from compressors in your rig or on your channel in the mains.
Place a foam wedge or towel between the body of the bass
and the tailpiece if you still have feedback.

11.Weave a strip of velcro through the afterlength of the strings between the bridge and tail piece.

12. If there is no PA and you are trying to get your rig as loud as you can put it in front of you pointing out at the crowd. You'll hear it just fine and it won't feed back near as much as if it's behind you or beside you."


Carolinabassist said:
I had the idea to fill the body about half full with a type of canned, expanding foam insulation called "great stuff". I understand that this is going to lessen the natural acoustic tone of the instrument and devalue it greatly (from the enormous $500 it's worth now) but is there any reason why this isn't worth a try? has anyone tried this before?
Click to expand...

Don't Do It :rollno:

Carolinabassist said:
Last note, i spoke with my luthier and he told me if it went horribly wrong he'd remove it for me for $100. so all in all it won't be impossible to reverse.
Click to expand...

Possibly true, but it may splinter, or even break the top on the underside. Double Basses are carved on the inside of the top and around the F holes, to resonate specific frequencies. You don't want to mess with that.:bawl:

Ric
 
#17
I know a guy who used expanding foam in his bass to cure feedback issues. I can say that the feed back absolutely went away 100%. Unfortunately so did most of his bass. He put too much foam in and watched it expand to the point that it began coming out the f-holes and then popped every seem on his bass. In the end he had a neck and a bridge left. But no more feedback, so in the sense it works great.
 
#18
you guys---if it's one or two notes causing the feedback the easiest way is to notch it out. That's the absolute first step. Why screw up the sound of the bass? If it's feeding back all over the place (which I doubt) then other more drastic measures are needed. I tour around the world and play loud A LOT and I deal with these problems a lot. A simple parametric pedal should do the trick and sound the best.
 

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