Damping to combat feedback?

bigfrog · #1 07-03-2006, 02:15 AM

I am having feedback problems - OK, it seems to go with the territory, but I am fairly new to URB. My pickup is a K & K Bass Max, and it is fine through my little Trace Elliot head and Warwick 4 x 8 cab, if I’m careful with EQ and positioning.

My worst experience yet was last weekend at a big open-air gig, where I stupidly trusted the PA guys, and left my rig at home (yeah, I know!). The line check was OK (good level in wedge) but as soon as we started up, the bass from the big PA just came right back through the wooden decking that formed the stage. (The PA cabs were also standing on this decking - eek!)

The sound guy’s solution was to pull almost all the bass from FOH and monitors, leaving the audience and my band with virtually no bass. I only survived the gig by using my ‘emergency’ in-ear system.

My first question is – do people use any damping with their basses? The tailpiece section seems to be pretty boomy when tapped lightly. I was wondering about a cloth or piece of foam stuffed down between the tailpiece and the body.

Also, the sound from the PA was mainly coming back up through the stage. I had the rubber foot on my spike - do people use even more acoustic isolation than just this?

Thanks, BF

fish slapper · #2 07-03-2006, 08:34 AM

I can't take credit for this. Search the threads for the proper source. Someone here suggested a nerf ball under the tailpiece. I tried it at home and it seemed to work. Haven,t needed it at a gig (whew) so haven't battle tested it yet, but its in my bag at the ready for next time.

**Chris Fitzgerald** · #3 07-03-2006, 10:46 AM

Here are three links to previous feedback threads. Good luck!

bigfrog · #4 07-03-2006, 12:15 PM

Thanks guys! What's UK-speak for nerf ball?!

BF

fish slapper · #5 07-03-2006, 01:07 PM

Well I googled "nerf ball" and came across this:

http://grouper.com/GlobalMedia/Media...1&s=6&q=118575

Hilarious. Nerf balls are soft balls originally marketed in the 60s so kids could play ball indoors and not break anything. There are a million varieties now (I suspect the patent has expired). Mine is actually a "squeeze" ball given away by my health insurance provider. I think they thought I would use it at my desk to relieve stress or strengthen my hands or something. Little did they know...

I believe the original poster of this idea said he was using the Nerf football.

**Adrian Cho** · #6 09-09-2006, 01:54 AM

I use the VibraMax from Lemur. It's a short piece of rubber tubing with stoppers at each end. You thread it around the strings near the tailpiece and it helps to dampen some of the vibrations.

Fred W · #7 09-09-2006, 07:55 AM

Something I first saw Mike Richmond do: Cut out a rectangular piece of foam and squeeze it into the bass f hole. It works.

tornadobass · #8 09-09-2006, 04:46 PM

I have two toys to stop feedback, plus a trick with my preamp.

One toy is a piece of heavy duty velcro that can be wrapped around the afterlength of strings to keep them from taking off with feedback.

A second toy is a piece of old keyboard wristrest foam, used much like the nerf ball idea. That dampens the tailpiece, which seems to be a big source of feedback.

Combining these two toys adds focus to the sound, but loses a bit of URB character.

The preamp I use is an older Fishman Pro-EQ. It has a neat switch that maybe some other preamps also have...a phase reverse. If the bass is feeding back, just flip the switch and the feedback is gone!

Greg Clinkingbeard · #9 09-10-2006, 09:18 AM

Quote:

Originally Posted by tornadobass

The preamp I use is an older Fishman Pro-EQ. It has a neat switch that maybe some other preamps also have...a phase reverse. If the bass is feeding back, just flip the switch and the feedback is gone!

The Fishman is great. The Depth, or Notch control on mine, is good in cutting all bass below a chosen frequency. That in conjunction with the phase switch does the trick.

fish slapper · #10 09-10-2006, 10:57 AM

Quote:

Originally Posted by clink

The Fishman is great. The Depth, or Notch control on mine, is good in cutting all bass below a chosen frequency. That in conjunction with the phase switch does the trick.

I have an Acoustic Image Clarus with the cut/notch feature as well. Takes some twiddling but you can dial feedback out. But I just had a Full Circle installed and I almost can't make it feedback.