avoiding (sound) feedbacks in concerts

[haggai]

hi, I'm having lots of problems with my bass causing feedbacks
during concerts. seems no matter where i play, or how pro the soundman is, the bass simply amplifies whatever bass it gets from the monitor, be it me, or even the keyboard or trombone.
I've tried cutting and fitting spunges to the the shape of the "f" openings in the body, but i'm still uneasy every time, waiting for that next feedback.. can anyone please advise me? thanks!

[Co.]

When you have feedback problems a phase switch helps a lot. Certain frequencies, that otherwise would be exessively overamplified are being cancelled out to some degree, so your amplified volume can get much higher before feedback.
You write, that the bass amplifies trombone, etc as well? That might be aproblem of your pickup system. Some pickups that are very close to the body, like the Realist for example, can make your bass to a giant mikrophone, that picks up everything that is on stage. You might consider getting a pickup, that is closer to the strings.

[Uncletoad]

This has been discussed in great detail on this board. Click on these links and read through some of the suggestions.

Post more questions if something is not clear or you are having trouble applying some of the suggestions.

Too much feedback.

Stopping Feedback in LOUD Settings

Feedback Eliminator?

[haggai]

well, thanks Uncletoad and Co., i've read through the linked threads, they did give me a lot to think about. but, i am still uncertain about how i should handle this next issue:
i play in a 7-piece traditional ska band, in which i also sing lead, and we are headed out for touring our first tour this summer, with rented equipment, less than 2 months from now.. most of our shows would be in festivals, some would be clubs, some indoors and some outdoors. now, my equipmnent (which will be left at home due to air travel issues) is a wonderful kay bass (don't know the exact model), with a realist, and i amplify it with my old BG warwick "profet III" amp, and it's 2 cabinets (2x10, 1x15) . since i sing lead, during shows i stand well away from my amp, but never send the bass through my monitor, or else i suffer severly, feedback-wise. AND THE QUESTION IS: what intrument/equipment should i rent for this tour? i hate the thought of renting an EUB, but maybe that's the safest way to go..? please advise.. thanks!

[Uncletoad]

I'd change the pickup from the realist to a Full Circle or a wing mount like the Bass Max and carry a preamp EQ like the Fishman Pro Platinum Bass EQ for when you use rented backline.

Keep the backline small, stage volume low, and keep floor monitors away from the bass. If you can use in ears while traveling that would be best if not put nothing but vocals in the monitors and point them away from the bass as much as possible.

Think of the bass as a huge mic or antenna that is gathering all kinds of junk sound you are trying to avoid. Keep everything well away from it if you can.

[salcott]

"Think of the bass as a huge mic or antenna that is gathering all kinds of junk sound you are trying to avoid."

Uncletoad speaks the truth. The laws of physics dictate that the acoustic bass is an instrument not suitable for high volume applications. Once you start stuffing damping and muting material in your bass, it might as well be an EUB. Get one and get used to playing it; you'll wonder why you waited.
Renting an upright is another can o'worms entirely. You have to learn a new instrument for each gig, and can also injure yourself (as I did) trying to tough it out on a badly set up bass.

[haggai]

thanks for the advises! i've learned a lot, and now have to choose carefully. i'll let you know how it turned out..

[dgelting]

A contact / magnetic pickup combo might be a good option too - you could blend the two (lots of preamps will do this) and try to get a balance of no-feedback-making magnetic and more-acoustic-sounding contact pickup.

[Dbassmon]

A preamp that has a notch filter is a handy thing to have for dealing with feed back. It removes a narrow Q or band of a frequency and is sweepable. You find the resonate frequency, the one which is causing you problems, and dial it down.

[Silversorcerer]

I played an outdoor festival last year with my carved Kremona 5-string and they had me loud enough to be heard acres away. I rarely play that loud with my slab / Ampeg gear. It was the ultimate. Nothing stuck in any holes either.

Here is the config:
K&K Bassmax mounted in the bass side bridge wing.
DPA 4021 condenser mic mounted on the afterlengths (many other cardioid mics would substitute).
Approximately same channel gain (about 9 o'clock) on both pickup and mic, slightly favoring pick-up.
No pre-amps on either the Bassmax or the mic (DPA mic has built in pre).
Acoustic Image Coda III on the front end, Master Gain 12 o'clock, notch filter invoked on both channels at the same (culprit) frequency, about 120 Hz on that stage. This button also reverses the phase of the amp signal to the vibration of the bass top. This is the magic bullet, IMO.
EQ flat on both channels
Direct out to the board.
Effects send out of the DPA mic channel to an SWR combo with an 18" speaker about 10 feet directly behind me and also driving a Hartke 4x10 cab, also directly behind me.
With that SWR rig behind me, the sound guys could take me out of the monitors. Trick is staying in front of the speakers so that the bass body casts a sound shadow on the mic.

It was awesome loud and no feedback. Total pro soundmen too. No soundcheck!!!

Two other double basses at the same festival. Different front end and pick-ups, same SWR / Hartke rig. One fellow was doing a lot of slap and he had the K&K Bassmax with an additional transducer on the fingerboard. Particularly fat sound with a lot of punchy attack. The other two guys couldn't get as loud, but nobody had any runaway feedback issues. I think that has a lot to do with experienced sound techs who have experience with DB's. It can be done.