Feedback Destroyer help needed, please!

[Rockin John]

Cutting a very long story short, I recently bought myself a Behringer FBQ2496 Feedbcak Destroyer. We always seem to struggle with feedback anyway, but the prime reason for buying was that I now have radio on bass and on mic as the plan is for me to go off into the dancefloor. I reasoned that the best plan to avoid feedback whilst I'm wandering about was to get the processor. Hmm.....

Unfortunately, this unit doesn't seem to work well. From experiments at home I'm convinced there's nothing wrong with it. So I'm equally convinved the issue is about my lack of knowledge understanding and 'nouse' about live sound and feedback killing and, therefore, how to get this thing to run.

Yup, I've read the handbook and I'm technically literate! But I can't seem to make the unit kill feedback.

Wisdom, guidance, and help always appreciated.

Thanks.

John

 

[el_Kabong]

You'll have to elaborate a bit RJ. What exactly is the box doing and what are the experiments you mention? How many mics are you using on stage? Forgive me if I'm stating the obvious but you do know the term feedback killer/destroyer is marketing speak? Those devices will not totally eliminate feedback, they let you get a few more db of gain before the feed back starts (which is great when you need it!).

Have you tried it at a rehearsal or a gig yet? I've got one of the earlier models and it works ok within it's limits. I get the best results (after setting the pa up properly) setting all the filters to roaming rather than static. Slowly push the gain up on the mics that the box is filtering until it starts to feedback. You'll hear the frequency get suppressed and see a filter lock. Repeat until you get to the last filter and you're ready to go.

You may still get the odd squeal or two as things settle when the band starts, or if you are simply driving the system hard. It will still feedback if you keep increasing the gain, just at a higher volume. Don't forget you can get feedback from the FOH as well as the monitors so you may want to bring that up and let a couple of filters pre-allocate themselves there too. If the filters are set to roam they will catch it from the FOH anyway but it might help avoid a squeak or two when the band starts.

Wandering around with a wireless mic can be challenging, if you get too close to the FOH it's going to feedback, processor or not.

 

[Rockin John]

Hello el kabong, and thanks for your trouble.

To begin with, let me describe what I tried at home. Radio mic O/P into FBQ2946 I/P (cos a mic wont drive the FBQ). Radio mic O/P to practice amp I/P. There's enough gain to get feedback if I get close enough to the loudspeaker. I have the SPEECH button depressed.

I quickly press the LEARN button to start the FBQ. It appears to do nothing! So I get the setup feeding back by waving the mic near the spkr, but still the FBQ appears to do nothing. No filters appear to be selected as shown by the front panel. IOW, the FBQ doesn't seem to recognise the presence of feedback even though it's taking place.

So I press and hold the LEARN button to start the AUTO LEARN sequence. Wave the mic again. This time the FBQ delivers pulses that instigates feedback. Eventually the whole set up is screaming but then, somehow, the FBQ stops the feedback and the mic can be used as normal. The front panel still shows nothing, though.

Maybe I've not set this up at home with enough gain. I may try it again but use my SM58 to the FBQ, via my mixer.

Anyway, hope that's enough for the moment for you to understand what I'm doing.



John

 

[TimmyP]

Do not let the filters float. Once they set, they should stay set ("one shot" some manufacturers call it).

Keep in mind when ringing out that you must duplicate the performance situation. Ringing out with an open stage (turning the level up until it rings, then EQing the ring away) may or may not apply to the performance situation. In a multi-mic situation, where the noise-makers (mouths and instruments) are using the mic at near 0 distance, ringing an open stage gets few if any of the frequencies that will feed back when a hand, face, open mouth, or reflective instrument top (or even a hat brim) are in front of the mic. In the case of the one mic bluegrass performance, the open stage is pretty close to the performance situation. But don't forget to add the missing bits: the reflective guitar top that will bounce sound from the room or monitor into the mic, the hat brim, or - ? Even once you seem to be done, when soundcheck starts you may get additional "hot" or "loose" (not feeding back, but trying to) frequencies that need attention. (Always end the soundcheck a little loud, to hunt for such spots.)

 

[Rockin John]

Thanks!

Actually, I've been away from this thread for a while but can now report that I've worked out how to use the Behringer.

Unfortunately the instruction manual isn't that that good: it either assumes more knowledge of these matters that I possess (=almost zero), or its simply isn't well written! Either way, I couldn't figure how to make it work. Even now there are a number of aspects to it I don't understand.

Anyway, I can now let the kit do it's work and have discovered it does a good job. TimmyP's advice now becomes valuable because I know what to do in the live situation. Thanks! I can wander about in front of the FOH and not howl the place down. Hopefully I can get this sorted before our first gig in a fortnight.

John