Behringer DEQ2496

[kblackmore]

Gentlemen,

Does anybody know how to use the DEQ2496 as a feedback removal tool? I have read the manual several times and have yet to figure this one out. I initially bought the unit for room EQ, which worked decently until I did some research into room acoustics and found I was wasting my time trying to solve problems in the room with EQ, so the unit has been sitting idle in my garage for about 3 years. I have a fairly important wedding reception to DJ next month and the room is very reverberant, so I have concerns I might get some feedback in the mic. Any input would be greatly appreciated.

[kblackmore]

Re: Behringer DEQ2496

Before I forget to mention, the unit will have the mic (wireless) channeled through it before going to the mixer. If that setup is incorrect, please let me know.

[Paul O]

Re: Behringer DEQ2496

Preventing feedback with live mics is more about keeping the mics behind the speakers and making sure the speakers are EQ'd flat. Feedback eliminator processing can be anywhere in the signal chain but to accomplish speaker EQ and feedback suppression at the same time it would need to be after the mixer and before the speakers or amplifiers. My experience with Behringer FBQs suggests you have to have a pretty hot signal through the processor and be experiencing some ringing(feedback) before the unit will lock in on it and set a filter, so ideally you want to set everything up in the venue and "ring out" the system meaning crank up the gains to see where the first 3 or 4 feedback frequencies occur, set and lock these into the processor, and then leave another 3 or 4 filters to roam. You don't want the processor to apply dozens of filters as it will really start to hurt sound quality, and you don't want those roaming filters to stay locked for more than about 5 seconds, that should be enough to kill any problems that arise and then they are free to clamp down on a new frequency. But if the system is setup and EQ'd correctly to begin with you should not need much feedback suppression, I have done many live shows with quality powered speakers that have a flat response and used absolutely no system EQ or feedback processing and had no feedback issues.

[Sydney]

Re: Behringer DEQ2496

Preventing feedback with live mics is more about keeping the mics behind the speakers...

Agreed...
Microphone pickup patterns have to be placed with regard to sound sources including reflective surfaces.
As this is a wireless mic - it is very easy for a user to travel in and out of sound modes and nodes and trigger feedback at many different frequencies.
A careless microphone operator gets the filters on feedback eliminators to kick in and can ultimately dull the mic signal, and a board operator has to gain ride.
A savvy mic user will be aware of where/how feedback is likely to occur and confine movement to minimize feedback.

[kblackmore]

Re: Behringer DEQ2496

Unfortunately, as this is a wedding reception, the mic will be wandering for toasts whereas nobody will be behind the speakers. I have no intentions of cranking the system, but the room is painted cinder block construction, my guess being 20x50 feet. The room is very reverberant. The speakers are to be located at the dance floor section (exact location to be determined). I am hoping by filling the room with people, it will tame the acoustics some. The speakers are (2) EV S-152 speakers on stands probably 5 to 6 ft high and a homebrew sub I built earlier. System is a Mackie 12 channel mixer, Behringer FBQ 2600 EQ, Behringer DEQ 2496 sound processor, Behringer CX 3400 crossover, QSC 1200 amp for the top speakers and a QSC MX 1500 for the sub. There is also a 2 channel Roland compressor I use just after the mixer to limit volume.

Would you suggest I place the Behringer DEQ2496 after the mixer and try to eq the system first and place the FBQ 2600 between my DJ controller and the mixer? I have always used the EQ's to make the music sound as clean as possible. I have never been a DJ to really use the mic, so I never was concerned about the mic issues. Now I have some lady singing through the system for a solo (probably in front of the speakers also), then they will also pass the mic for the toasts. I am seriously concerned on this one as I want to make the best possible showing (possible future gigs could result).

[Sydney]

Re: Behringer DEQ2496

... the mic will be wandering for toasts whereas nobody will be behind the speakers. ...Now I have some lady singing through the system for a solo (probably in front of the speakers also), ....

This guarantees a constant feedback issue, and EQ will not alleviate.
I have dealt with similar scenarios by having someone on the mixer gain slider to pull down at the onset of feedback ( ie gain riding ).

http://www.mediacollege.com/audio/howto/feedback.html

Feedback eliminators have to be used carefully - note this scenario about 2/3 down this page

http://www.allchurchsound.com/education/edart/FBE.html

[Paul O]

Re: Behringer DEQ2496

The speakers are (2) EV S-152 speakers on stands probably 5 to 6 ft high and a homebrew sub I built earlier. System is a Mackie 12 channel mixer, Behringer FBQ 2600 EQ, Behringer DEQ 2496 sound processor, Behringer CX 3400 crossover, QSC 1200 amp for the top speakers and a QSC MX 1500 for the sub. There is also a 2 channel Roland compressor I use just after the mixer to limit volume. .

Here are my suggestions. Insert 1 channel of the Roland on the mic channel and set it up as a brickwall limiter to prevent the untrained speakers from overloading the mic channel. Set the threshold high enough that speakers aren't normally triggering compression, it's only when somebody screams into the mic that it should clamp down.
Do you have a measurement mic? It's pretty much a guarantee your passive speakers can use some parametric EQ, if you had a test mic you could download a copy of REW(it's free), measure the speakers response and apply some PEQ with the DEQ2496 to tame any nasty response peaks. With that done setup the signal chain as follows..

Mixer - DEQ - FBQ - CX2400 - amps. The FBQ graphic has feedback indication on it and you will be able to see ringing begin to build and pull down the corresponding slider before the auto filters in the DEQ will activate, you just have to keep an eye on it when people are speaking. Set the graphic totally flat to start the event, if you want to customize the sound of the speaker system use the DEQ to do it.

Overall I think if you can measure the speakers response and apply some parametric filters with the DEQ you won't have any feedback issues.. even with the wireless mic wandering the room in front of the speakers. My system is used like this all the time and the only time feedback occurs is if somebody stands right in front of a speaker at point blank range with the mic towards the speaker. Otherwise there are zero feedback issues no matter how reverbant the venue is.

[kblackmore]

Re: Behringer DEQ2496

Much thanks. Will setup in house a couple of times so I can get better acquainted with 2496. I have the ECM 8000 mic and a copy of Room EQ Wizard, just never linked the software and 2496 together before. I have a little time before this gig, so I'll set it up and get ready.