Why am I getting feedback no matter what i do?

hermanmunster · #1 10-10-2010, 11:27 PM

I seem to get feedback no matter what I do. I have a Allen & Heath zed 12fx, Sm58's single 15's jbl's and monitors. I get feedback in every venue we play. It's not a constant feedback but a ring here and there to the point it's a problem.
I check the gains with the PFL then raise the slider for each channel I'm using prior to playing and they are good. main speakers are out front with the monitors for the band. It's not a constant feedback but an anoying ring. Any help would be a help. How do I get nice punch on the vocals without feeding back? Thanks.

rodl2005 · #2 10-11-2010, 01:30 AM

What JBL's are they. I've found with the better quality PA gear the LESS U have t do. eg. we use our Yamaha EMX or PMX88s or sumthin' into Yammy (Good ) spkrs & we'll have to EQ a little. When we use our OLD JBL SR4725 1x15's with an old German made Dynacord- powered mixer- NO EQ at all. NONE -oh OK a li'l on each channel but NO graphic!!!!!!!

& it ALWAYS sounds amazing!!!

JBL- while I LOVE some- do make some rubbish.. I AINT sayin yours are no good, just some seem to have probs in any room.... & some....

I'd buy one o' those modern feedback eliminators- they notch out a TINY range of the prob Hz & seem to work really well. .

Zooberwerx · #3 10-11-2010, 05:53 AM

Which is feeding back...the FOH, monitors, or both? What methodology are you using to set your mic input gains / trims? Same question stands for you power amp attenuators.

I'd pass on the feedback eliminator for now and concentrate on finding the cause.

Riis

modulusman · #4 10-11-2010, 06:09 AM

As mentioned above what model are you using for mains/monitors? You should get some 31 band graphic EQs.

rodl2005 · #5 10-11-2010, 05:41 PM

+1 to all above suggestions (after mine ;-) ) 31 band EQ's will go a LONG way to help eliminate the prob freq/s. & DEFINATELY find out if it's FOH or monitors feeding back. Then get back to us.....

James Judson · #6 10-11-2010, 06:25 PM

Feedback is all about the relationship of microphone and speakers. Anyone that has access to a mike needs to be aware of this. I've seen a ton of "musicians" that point the mic right into a monitor inbetween songs and wonder who is doing this. Moving monitors or mics can go a long way to reducing feedback. Also make sure monitors are pointing to the back of the mic (singer is singing into the front).

How do you get rock volumes without feedback? Easy answer. Lower your your stage volume and let FOH speakers do the work. Your guitard will say "if I turn down my Marshal stack down I'll loose my tone". Fire him. You will always have a hard time with feedback when you compete with a narrow minded guitard. There are a lot of guitards around.

Adjusting equipment? Each and every mic, cable, mixer, efx processor, amp, speaker cab and room has frequencies that they like and dislike. This makes for a complex mess that makes a sound man work for his pay. A graphic EQ will go a long way to dealing with this mess. I recommend a 31 band EQ on every amp. After a while you will hear a ring and know what freq it is and your finger will just lower that freq and it will be gone. You will also hear a ring and not know what freq it is. I used to boost each freq one at a time till I found the freq cuz it just got worse. This method will not make you any friends but it works.

Me??? I'm usually the singer, bass player and sound man. My brain ain't big enough to do all three at the same time. So I go for high quality equipment. First of all I throw away the 58's. 58's are great mics but they make a sound man work. I like Audix OM-3's but there are a lot of mics that have a close proximity effect and that means good feedback rejection. If everyone is using the same mic, your job will be easier cuz when the first mic is dialed in the rest fall right into place.

Summary: Change out the mics, add EQ's and turn down.

Good luck.

walterw · #7 10-11-2010, 08:33 PM

Quote:

Originally Posted by James Judson

Summary: Change out the mics, add EQ's and turn down.

we can argue about the mics (58s are still pretty good and pretty popular) but no argument about the last two suggestions.

EQs serve to knock out the feedback, as well as "sculpt" the mix overall to sound better.

turning down always makes mixing easier.

hermanmunster · #8 10-11-2010, 10:08 PM

Thanks for all the input. I agree the band plays way to loud. I'm hearing it in the mains and and monitors. Last night it seemed like I only had trouble with one mic. It seemed like everytime the drummer would hit his ride is when I would hear it and the mic in question was out in front it about 4 or 5 feet away. The speakers are not the highest quality but not the worst either. They are the MRX series. I moved the monitors a few times trying to see if it would help but no go. I'll try an eq the next time.

hermanmunster · #9 10-11-2010, 10:10 PM

To ad, I set the input gain with the PFL engaged then adjust the slider.

Stumbo · #10 10-12-2010, 03:46 AM

Maybe the mic stands are vibrating on stage.

Sometimes if the bases are not isolated, they will vibrate, causing a ring. Maybe the rubber feet are gone from the mic bases. Try putting a piece of rubber under each stand. Same for each speaker cab.

No downside to testing this out.

groove pump · #11 10-12-2010, 12:44 PM

Note of thanks to James Judson. I learned something today.

KeithAlanK · #12 10-13-2010, 10:49 PM

Any monitor feeback will also come out of the mains, so to narrow down the culprit I always soundcheck with monitors off to get the FOH mix, then with mains off while adjusting the monitors.
Sometimes it takes both mains and mons reinforcing each other to cause feedback, and that's when a good 31-band saves the day.