Feedback Destroyer?

[qster]

I get a lot of Microphone feedback in my home Karaoke system because the system is setup at the end wall of a rectangular room and the speakers are facing the singer. I tried to turn the speakers 45 into the side walls, but didn't seem to help, the only thing I can do to eliminate the mic feedback is to turn the volume down very low.

I've looked around and found the Behringer SHARK FBQ100 which seems to be the solution, does anyone have experience with this device? would this device help eliminate the mic feedback so I can turn the volume a little louder?

[MikeRivers]

Your problem is how the room is set up. You'd be better off moving some furniture so you could locate the speakers so they weren't pointing at the singer than buying a gadget. Really. Even if you have to put the speakers slightly behind the singer, with a good hypercardioid microphone (dare I ask you what microphone you're using now?) you can take advantage of its null and set up so that the speakers are pointing into the mic's null.

 

Feedback tends to occur at a few specific frequencies (which are a little different for every room). What a "feedback destroyer" does is automatically locates those frequencies and tunes notch filters to reduce the system gain at a few of the primary feedback frequencies. Most of them work in a mode similar to how a live sound engineer "rings out" a system. With the mic and speakers in their normal operating position, you increase the gain slowly until feedback just starts, and let the "destoryer" detect that frequency and notch it out.

 

Then you raise the gain some more and let it find and attenuate the next feedback frequency. Generally you'll have a usable improvement, maybe 6 dB more gain before feedback, after notching out about four frequencies, maybe five. You then lock in those filters and put the gadget in a dynamic mode where if it hears feedback at some other frequency, it will duck it down quickly, and after a short time, will release that frequency's filter so it can do its job on another frequency when one comes along.

 

These things don't destroy feedback, they can reduce its occurrence somewhat at a given gain setting. The tradeoff is that your system has dips in the frequency response that may affect the sound. If you have a single microphone, as typically you do with a karaoke setup, and your system allows you to put the feedback destroyer in line with only the microphone (you can do that with the Shark FBQ100) then the filters will only affect the singer's voice. If you have one that you have to send the whole mix through, then the filters affect the sound of the music as well as the voice.

 

I'd say give it a try. You can buy one from Amazon for $150 without even changing out of your pajamas, and send it back if it doesn't help you as much as you had dreamed. But consider rearranging the room first.

 

[Drummer44]

I get a lot of Microphone feedback in my home Karaoke system because the system is setup at the end wall of a rectangular room and the speakers are facing the singer. I tried to turn the speakers 45 into the side walls, but didn't seem to help, the only thing I can do to eliminate the mic feedback is to turn the volume down very low.

I've looked around and found the Behringer SHARK FBQ100 which seems to be the solution, does anyone have experience with this device? would this device help eliminate the mic feedback so I can turn the volume a little louder?

 

 

Assume you mean the speakers and the singer are both near the same end wall? On the "stage?"

 

Try locating the speakers at the way other end of the room, facing back toward the "stage?"

 

-D44

 

[qster]

(dare I ask you what microphone you're using now?)

I recently purchased the EV N/D 967 which sounds great but gets a lot of Feedback, I intended to use the Feedback Destroyer for this mic.

I also have a Shure 58 which rarely gets the Feedback issue but it doesn't sound as good as the EV.

 

and your system allows you to put the feedback destroyer in line with only the microphone (you can do that with the Shark FBQ100) then the filters will only affect the singer's voice.)

This is what I'm hoping to do with this device, connect the Mic to it then connect it to the Mixer.

 

With the mic and speakers in their normal operating position' date=' you increase the gain slowly until feedback just starts, and let the "destoryer" detect that frequency and notch it out.[/color']

 

Then you raise the gain some more and let it find and attenuate the next feedback frequency. Generally you'll have a usable improvement, maybe 6 dB more gain before feedback, after notching out about four frequencies, maybe five. You then lock in those filters and put the gadget in a dynamic mode where if it hears feedback at some other frequency, it will duck it down quickly, and after a short time, will release that frequency's filter so it can do its job on another frequency when one comes along.

Thanks for the detailed instructions, extremely helpful for novice enthusiasts like me. I'll give it a try.

 

[qster]

Assume you mean the speakers and the singer are both near the same end wall? On the "stage?"

 

Try locating the speakers at the way other end of the room, facing back toward the "stage?"

 

-D44

 

Unfortunately I don't have any option for rearranging my family room, it's not a very big room (about 14X18), the end wall is the only place where I put my TV and my sound system so the family can watch TV from open area at the open other end (connected eat-in kitchen). So I can't really move my "stage". The singer would be positioned about 8-12 feet facing the TV and sound system.

Since I can't change my setup, I'm hoping the Feedback Destroyer can help

 

[MikeRivers]

I recently purchased the EV N/D 967 which sounds great but gets a lot of Feedback, I intended to use the Feedback Destroyer for this mic.

I also have a Shure 58 which rarely gets the Feedback issue but it doesn't sound as good as the EV.

 

I would have guessed what you have observed. The primary reason is that the EV mic is considerably more sensitive than the Shure - that is, it has a higher voltage output for the same acoustic sound pressure. You might simply try turning down the gain with the EV mic and getting a little closer to it. That way you can get the volume that you're used to hearing (or would like to hear if feedback didn't get in the way) but the system gain would be lower so there would be less tendency for feedback to start.

 

The ND967 is a supercardiod mic which means it picks up less to the sides than the SM58, so it should really help with the feedback, but unless you're running the volume control lower with the EV than with the Shure, you're probably picking up just about the same amount of ambient sound with either one, which is working against the benefit of the tighter pattern.

 

[dboomer]

A tighter pattern is only a benefit wrt feedback if you can use that pattern to your benefit. I think it is a mistake to assume that a super cardioid mic will always help with gain before feedback. It all depends and in some cases it will be worse than a cardioid mic. In a very small room like this one your primary cause may be the reflections off the wall behind you that go straight back into your mic. Mic pattern isn't gonna matter much in this case. If you were to take the same system out in the middle of a football field you would probably never have feedback. Small rooms are the enemy but if you have a 30' proscenium you won't have much problem.

 

 

 

The the easiest thing you can do is get very close to the mic (eat it!) as every time you can cut the distance from your mouth to the mic in half you can improve the GBF by a factor of four. So going from 1 inch away to 1/2" away will give you a 6 dB improvement. It's also very important when using a super cardioid mic to stay exactly on axis with it. Both tone and gain suffer quickly if you get even a little off to the side as compared to a cardioid mic.

[MikeRivers]

A tighter pattern is only a benefit wrt feedback if you can use that pattern to your benefit. I think it is a mistake to assume that a super cardioid mic will always help with gain before feedback. It all depends and in some cases it will be worse than a cardioid mic.

 

Of course. There are few "always" things in acoustics. If it was possible to re-arrange the room so that the singer's back was toward the speakers, the off-center nulls of a supercardioid might attenuate some of the direct sound from the speakers. And if reflections were coming off the walls, the greater attenuation at 90 degrees over a caridioid might be helpful.

 

 

[WRGKMC]

I use a pair of Sabine Feedback eliminators for my PA rig. They are considered to be one of the best made.

What they do is self detect the feedback frequencies and create narrow EQ notches to eliminate the feedback. You can then get the sound a little louder before another harmonic frequency begins to feedback at a lower frequency. The units will continue to create notches until all 12 notch filters are used up. By then the vocals are louder.

 

The problem is this frequency notching does come at a cost. You can wind up with muted tones if you overuse them. I found that having matching mics on stage is essential too. You have one oddball mic and it will create oddball notches for the other mics.

 

I read up on the Behringer. I don't think its an automated system. I believe it gives you feedback detection by illuminating led's at the different frequency bands and you have to manually turn the frequencies down.

 

Its worth a shot. Just don't expect miracles. Cutting feedback comes at a cost and its better to use a mic that has a shorter proximity, less sensitivity. Something like an SM57 is very directional and prevents allot of the back feed if you're facing the speakers. Speakers themselves are a big factor too. Horns can be long throw or short throw and anywhere in between. You'd want short throw like stage monitors in a tight room so the highs disperse widely to minimize feedback. A long throw narrow horn will shoot the highs into the mic like a laser beam.

[Mandolin Picker]

I read up on the Behringer. I don't think its an automated system. I believe it gives you feedback detection by illuminating led's at the different frequency bands and you have to manually turn the frequencies down.

 

Behringer actually does have an automatic model. We have the FBQ 1000 in our portable rig at the church (http://www.music-group.com/Categories/Behringer/Signal-Processors/Feedback-Suppressors/FBQ1000/p/P0A3R). It does help, especially if you set the system prior to anyone actually doing anything. But it also can cause a muddiness in the overall sound. And as also has been said before, it is not a magic pill, you can still get feedback if you aren't careful. For us it is more an insurance policy when we do an 'oops'.

 

I think you may have been looking at their 31-band EQ. It has a feedback detection system that lights up small LEDS on the faders so that you can remove the frequency manually.