Terrible feedback problems

Bowserjoe · #1 06-21-2007, 09:41 AM

For a while I always thought it was this one bass amp that was the problem because unless I stood in exactly the right spot in front of and to the left of it, and had it turned up no louder than so I could hear it, it would get horrible feedback that was 10x as loud as my playing. The feedback was always on note A for some reason. Figuring it was the amp that was no good, I switched to the other amp I have, which is an amp meant more for electric bass and really didn't sound great with the upright but at least the feedback problem was greatly reduced. It's still there however if I leave my fingers off the strings, or play an open A string. This is why I think it's my pickup that's the problem but I'm not sure...does anyone else have problems like this?

Thanks,
Bowserjoe

wingnut · #2 06-21-2007, 03:01 PM

Find where the "A" lies in the EQ and back off that particular band a little at a time until the feedback goes away. If it is just that one note, that should solve the problem. However if it is accross the board feedback that just happens to be more pronounced in the "A", you will need to do a few things. Let me know if the EQing works or not.

Bowserjoe · #3 06-21-2007, 05:44 PM

Quote:

Originally Posted by wingnut

Find where the "A" lies in the EQ and back off that particular band a little at a time until the feedback goes away. If it is just that one note, that should solve the problem. However if it is accross the board feedback that just happens to be more pronounced in the "A", you will need to do a few things. Let me know if the EQing works or not.

I just have a high, mid, and low knob on my amp, do you mean to see which one of those A is on?

bolo · #4 06-21-2007, 06:43 PM

You might could try dampening the afterlengths of the strings, like my pal tornader outlined below from another thread:

Quote:

Originally Posted by tornadobass

Something that helps with focus is to wrap a piece of thick velcro around the afterlenth of the strings, a bit away from the bridge. That cuts out ringing and keeps the strings from resonating there. A piece of dense foam under the tailpiece can also control resonant feedback, but it also cuts out some of the bass's character.

There are some pics floating around here somewhere if you need a visual.

Another frequent suggestion is getting your amp up off the floor by putting it on a chair, stool, or amp stand.

And if your amp or preamp has a phase reversal switch, give that a shot.

wingnut · #5 06-21-2007, 08:07 PM

Quote:

Originally Posted by Bowserjoe

I just have a high, mid, and low knob on my amp, do you mean to see which one of those A is on?

Correct. Also as stated earlier, there are a lot of things you can do to both the URB and your amp/system to help get rid of feedback. If you do a search on feedback, you will find a lot of useful info on the matter. It can be as simple as squeezing the bass between you legs to adding a preamp to your system. If you PM me I can go into a lot more detail.

Bowserjoe · #6 06-21-2007, 10:21 PM

Thanks for the help guys, I'll mess with the amp EQ and see if that works before I try anyhthing else.

bolo · #7 06-24-2007, 07:59 PM

Well ... Adjusting the EQ on a typical 3-band setup is gonna alter your tone, maybe in a way you'll like, maybe not. The afterlength dampening and/or cabinet height suggestions will leave your tone alone.

Petebass · #8 06-24-2007, 08:28 PM

Quote:

Originally Posted by Bowserjoe

The feedback was always on note A for some reason.

Assuming it's the A note on the open string, try cutting the Eq in the 220Hz region. At that note, the fundamental frequency is actually 110Hz, but the laws of physics being what they are, the second harmonic is usually a hell of a lot more audible than the fundamental. Therefore the frequency one octave higher is the "likely" culprit at 220Hz.

However, frequencies sometimes resonate in tendem with their octave counterparts. So if 220Hz doesn't fix it, try 110Hz, or 440Hz, or 880 Hz etc.

Hope that helps.