Equipment Question

[ddouglass]

Has anyone ever used any type of feedback destroyer/active filter to stop microphone feedback? Pros and Cons?

I have a couple of singers who have high pitched voices and sing too soft. This requires a very delicate balancing act between getting the microphone sensitivity up high enough to hear them without triggering feedback if they move within 20 ft of a speaker. I need someway to squelch out the feedback without having to constantly adjust the mixer controls.

[admin]

If I am right, inserting a 180 degree phase shifter in the output signal going to the amp/speakers will prevent feedback squeel.

[ddouglass]

That would work if you knew the exact frequency of the feedback. Unfortunately it isn't always the same frequency. I have had both high and low frequency feedback depending on what sounds were playing at the time the singer got too close to the monitor speaker. And those are only the frequencies within hearing range.

Actually, I was looking at the 2 or 3 models of automatic feedback suppresion units. These are supposed to trigger and set active narrowband filters to block any feedback frequency within 0.1 second or less. I was wondering if anyone had used any of these equipments and did they live up to their hype. Or did they reduce the quality of the overall output.

Thanks Admin, but even though I have spent my entire career both working in and teaching electronics, I would rather let someone else build the equipment, so I don't have to clutter my head with all those calculations.

[bobcox- with the Lord]

i use a peavy EQ with feedback locator, lights up the freq that is feeding back. best i have found. i have behringer feedback destroyers and a peavy feedback ferrett they will slowly shut down each freq till you have to turn it off and back on again. (slowly shuting down your system) so i only use them on my floor monitors.
peavy EQ is the way to go. easy to use and very good at fighting feedback.
hope this helps. Bob

[Monolith]

My dbx Driverack PA ( http://www.driverack.com/PA.htm ) with analyzer mic will be here this week and I should be able to use it this Thursday. It has an automatic room equalization system and feedback suppression as well as a host of other functions.

I will keep you posted how well it works.

This thing cost a bit $499 at Guitar Center but it answers a lot of questions.

I will use it to control the output from the board to the amp and I am also using a Behringer MDX 4600 4 channel compressor/limiter to save my ears (and those of the audience) from the people who either have no idea how to use a microphone or just like to scream at the top of their lungs.

This and all of the other stuff I have bought recently should make for an awesome sounding system. Then I can go back to upgrading my music collection.

Jon

[swany]

I don't turn the mic up unless I can safely, I've had a lot of people complain over the years I just tell them to put the mic closer to their mouth or speak up. Seems to work with most but not all. I do run peavey amps with the feedback ferret. I do have a feedback, setup new in the box never used it or even opened the box, got it with a system I bought a few years ago. Someone needs it let me know at my e-mail address it would be way cheaper than a new one.

[enolder]

Originally Posted by ddouglass

Has anyone ever used any type of feedback destroyer/active filter to stop microphone feedback? Pros and Cons?

I have a couple of singers who have high pitched voices and sing too soft. This requires a very delicate balancing act between getting the microphone sensitivity up high enough to hear them without triggering feedback if they move within 20 ft of a speaker. I need someway to squelch out the feedback without having to constantly adjust the mixer controls.

I'M NEW TO THIS FORUM SO I HOPE I'M DOING THIS RIGHT...YOU MIGHT TRY A COMPRESSOR /LIMITER...I USE ONE IN STUDIO AND IT WILL BRING UP LOW VOCALS AND SUPRESS OVERPOWERING VOCALS...BUT YOU NEED TO RUN THE MIC DIRECTLY TO IT THEN ON TO YOUR BOARD.

[Monolith]

For those of you who were interested. I finally got a chance to use the DriveRack on Friday. I did not use it on Thursday due to some incorrect connections that I had made. Let me say for starters that this thing is awesome and I'm not even using all the features yet. Should be well worth every penny I spent on it.

The auto-EQ function: Took a bit longer to EQ than I expected. I would recommend if you are going to do this either set up really, really early (when no one is there) or do this part after you are done for the night and your audience has left. Reason being is that the system generates pink noise (which sounds like old television static) and it can be very annoying. Use the RTA Mic that you can buy with it or one with an identical response and put it on a mic stand in the middle of your speakers about 15 feet back. Select your EQ level and let it do its magic. Takes a few minutes so be patient (I wasn't and had to do this part twice).
Once it is done fire up some filler music and have a listen. I was impressed......make that very impressed.

Auto Feedback suppressor: This was a snap to set up and use. Tell the system how many filters you want to have locked in and then hit start. Walk around the room and talk into the mic and it will lock in how ever many you have preset and the rest can change as necessary. The standard mic rules still apply so don't think this is a cure for a bad setup. You still can't stand directly in front of a high powered speaker. Once I set it I was done. The system took care of everything from that point on. I did have to make an adjustment to the time that the system held the remaining filters. It was too long and the driverack would run out of filters too soon. Easy fix couple of buttons and a twist of a knob. Recommend setting the floating filters to release at about 10-15 seconds. Enough time for the system to find and stop feedback until the mic has moved.

Subharmonic Synthesizer: Let me just say.......holy cow did that make a difference. All this thing does is identify where you want your subs to be and then put them there. My PR-15's sounded like much different speakers. Easy to set up...just push a button select your cutoff frequency and then adjust the gain up or down. Sounds beautiful.

Compressor/Limiter: Easier to set up than the other C/L I have in the system. Not a lot to speak of here. It did exactly what it was supposed to do and was easy to set up. I'm nopt sure I have it set exactly the way it should be so I will not make too much of a comment at this point.

I did not have a chance to mess with the other functions due a very busy night. But my over-all impression was this:
Absolutely awesome. It is amazing how much better things sound and how much more powerful my system feels with this simple addition. And by the way did I mention that I have the ability to save each of my setups as a preset so I don't have to go through this every night. Just walk in setup, power-up, turn the knob, push the button, and listen to the magic.

Also a quick note on a previous post about using a compressor/limiter. Most manufacturers recommend that you not connect your microphones directly to the inputs of the compressor limiter unless you have no other option.
Most mixing boards have 1/4" insert on each channel. This is for interrupting a signal as soon as it leaves the pre-amp and before it goes to the line EQ, slider, output knob (whatever you have following the insert port) . The reason behind this is that most microphones do not supply sufficient signal for the compressor function to work properly. You wind up with signals that are difficult to control and probably not doing what they are supposed to do. If you run your mic signal through the pre-amp on your mixing board, then out of the mixer to the compressor, and then back into it (via an insert cable from any music store) the signal is at a proper level for compressing accurately

Jon
Monolith Entertainment

[ddouglass]

Thanks Jon. Nice detailed report. I did look into it and decided I couldn't see the expense being worth it for the small club we play at, but will definately keep that one in mind for future expansion. Sounds like an awsome piece of equipment.

I am looking hard at the Peavey equalizer as my solution since we rarely have the feedback problem and hopefully we can curb it with that. Too bad they don't have the autotuning of the DriveRack. That would make it so much simpler to set up. I am also looking into upgrading my mixer to the Vocopro KJ-7800 to give me better control over existing equipment and add cross fading that I don't have.

[Monolith]

I understand about the expense. I cringed about dropping those credit card numbers. But I feel it was worth it and am happy wth my decision.

If you are looking for the best sound. You might look into some of the other major brands of mixers. VocoPro is not your best sounding option in most cases. They tend to be a lot more noisy than a pro audio mixer. I did a lot of research before I bought my mixer and compared a lot of different numbers before purchase. THD and noise are some major areas to look at. Talk to the folks in the Guitar Center or Sam Ash. If they are worth their paycheck (and most are) they can help to explain the differences between each brand and model.

You will find that in most cases there are some that stand out for abilities and clarity more than others. I have rarely heard a vocopro that could go toe to toe with a Mackie, Yamaha, or even Behringer (as a matter of fact the Behringer I use has it's Feedback detection system and EQ on the board itself and it only cost me about 200 bucks).

The feedback detection/EQ combos are great if you can babysit them. They work by identifying which frequency band on an EQ is experiencing feedback and then providing indication to that knob or slider so you can turn it down. An Equalizer is used to make each room you play in sound the same. If you have to start turning down your frequencies in bands as on an equalizer you are changing a large amount of the dynamic of the final ouptut. Which is where the feedback eliminator modules come into play. Most of the better brands give you the option of how wide an area of the total frequencies you would like to suppress and can be made to be completely temporary and return to previous setting after a preset amount of time (are any of us honestly going to remember to turn up the EQ again after feedback? I know I usually just leave it.) Also, you don't have to watch eliminators nearly as much, or have to, very quickly, figure out which frequencies are feeding back and adjust the level down.

Ask yourself all of the pertinent questions before you buy. Compare cost against functionality. What does one brand or model offer that another one doesn't and do you really need those extra bells and whistles or can you get them at a better price somewhere else. The only real advantages I see to the VocoPro is that you can change the key from the board instead of the player or program, the cross-fader, and the video outputs. If you have Hoster or most CD+G players the keychange option is not necessary because it is written into the program or part of the player, the crossfader really isn't that helpful if you get used too using two sliders or pots (and with the inconsistencies of most CD+G's it can often leave dead air if you aren't prepared), and a 1 in 3 out video splitter is about 5 dollars at Radio Shack.

Not trying to dissuade in any way and I never intend to offend...just an opinion and an assist based on my experiences. I believe in sound quality first and Karaoke/DJ music selection second.

Best of luck in your decision making process,
Jon

Edited portion:

Just noticed something else you and I have in common Dale. We get our other paycheck from the same uncle. You at Lackland?

[ddouglass]

Jon,

Yes I am at Lackland working in contract position but am also USAF Ret.
Thanks for the suggestions. As far as the equalizer goes since we only play in one private club once it is set there isn't much to change except when my sis-in-law (our other host) goes messing with it....lol.
We don't even have to move the equipment. The only thing we take home is the computer because I don't want to chance somebody messing with it.

Send me an email with your address and I'll send you an address for me at the base.