Feedback

[subharmonic]

So I am a mobile DJ and am not used to live sound. I have been having tons of issues with feedback. So most of my mic use is talking. I understand the principles of not being in front of the speakers etc. There was a drastic improvement between cheap and better mics. However when music is going there still is an amount of feedback that happens. I have a DBX Drivereack PX and a Behringer Ultracurve Pro 8024 running the feedback destroyers.

I don't want to use them though. Cause when I was testing my T-60 for air leaks. Even without a mic plugged in my Driverack kept filtering out my test tones, it drove me nuts until I figured out that was the issue. Until I turned off the feedback destroyer function I was baffled as why my tones would be strong, then less and less. If it does it on test tones maybe it does it during gigs.

So I was just wondering how you guys deal with feedback? I noticed even on fine notch filters mens voices that are deep would be robotic sounding.

[Frederic Gelinas]

1- Search for "ringing" monitors. Basically, during setup, you find the offending frequencies by bringing the gain up slowly and cut them down until there are many frequencies ringing at the same time. You already figured out that automatic filtering is not predictable/useable.

2- Getting a super-cardioid microphone can help.

3- Place your speakers elsewhere

4- Turn the master down whenever you're about to talk. (or have a compressor that allows ducking...)

[Tom Smit]

+1
...and, if possible, don't have any open mics

[James R]

Watch out for the feedback destroyers, they're ok for a acoustic act not at a loud volume.
I was told by a Behringer tech the filters have a hard time keeping up so sometimes generate feedback.
I used to use one, after I stopped and just tweaked the eq no more feedback problems

[Ron K]

Well here's the bottom line. With the PA at war volume you should be able use an open mic within 3 ft of either stack and clearly understand it.If not either you EQ set up is drastically wrong or you are using a pretty crappy mic or both.Keep in mind systems that are not time aligned very well are more problematic with feedback.Especially those where their are phasing problems and the operator is trying to correct the timing error with amplitude correction.

EQ the system to the room first.Then EQ the vocal mic through the system.

Try and keep the vocal mic from being in the subs. Either a good HPF set around 167HZ or run Aux fed subs.

I often High Pass that high for extreme levels in smallish type clubs and bars.A more normal setting would be down around 120 or so but it's largely determined by the room acoustics.

Ring out he mic in the room within 3 ft of either stack. Most often I find heavy cuts around 250Hz > 500Hz. Squeals around 3K and 5K and the zing up around 10K.When removing the 3 and 5K apply just enough cut to keep the squeals down.

I'd try and get a good parametric because they do far better with tailoring the output to match the source. 31 band graphics work but often you find yourself hunting too much and end up with a bunch of cut bands and a crappy sound.With a good parametric you can sweep the frequency (start with a wide Q like say 1.5) till you find the center that makes the most impact at say a 8db cut.Then start narrowing the Q till you get outside the range where the difference was first noticed. Then proceed to sweep as a fine tuning to zoom in on the most affected frequency while narrowing as much as is needed.

Lots of DJ type mixers are simply not set up to do justice to a good vocal sound. I'd maybe look at a MIC Pre to get to where you need to go but I have no clue as to what board you are using so it's hard to say.

Also a good MC vocal as does any vocal starts with a good articulate and loud voice. Plain and simple. The loudest sound at the Mic capsule wins and all that rapper mic cupping is bullshit so dont do it. It makes things worse.

FWIW a hyper vs super vs plain cardioid deal with off axis rejection differently but neither is better then the other. It's all about placement. Supers are better off axis rejection to the rear sides of the mic but have a HF peak right at the rear. If your wedges are shooting up the back the super is not very friendly in the HF! Each handle rejection a bit differently so learn the difference and pick a mic that will cover your positioning needs.

[quaizywabbit]

Get yourself a combo gate/compressor. The gate is the most effective in your environment, shutting off the mic when youre not actually speaking into it...

for dj work the Behringer Shark series units are probably what you would want to handle a single mic going into your dj mixer. handles feedback, gating, and compression... and only affects the mic signal going through it....not the mix as a whole like the driverack does...

[Dave Non-Zero]

a good HPF set around 167HZ

thats the first time ive seen someone mentioning what i always do! HP vocals at about 150-170 cleans them up great. ive been thinking its a bit high, but have to go with what my ears tell me i suppose so its good to get a bit of backup.

a good MC vocal as does any vocal starts with a good articulate and loud voice. Plain and simple. The loudest sound at the Mic capsule wins and all that rapper mic cupping is bullshit so dont do it. It makes things worse.

+1 million baggillion

[Ron K]

a good HPF set around 167HZ

thats the first time ive seen someone mentioning what i always do! HP vocals at about 150-170 cleans them up great. ive been thinking its a bit high, but have to go with what my ears tell me i suppose so its good to get a bit of backup.

a good MC vocal as does any vocal starts with a good articulate and loud voice. Plain and simple. The loudest sound at the Mic capsule wins and all that rapper mic cupping is bullshit so dont do it. It makes things worse.

+1 million baggillion

It is a high at 167Hz or so but...............when you run very high levels especially where you're using a high crest factor in smallish type settings the high HPF really does indeed clean up the vocal mix. The reason is their is still a sloping response down below the HPF and often at those higher levels it's more then enough for the growl of a male vocal. Lower the HPF at those levels and the whole rigs starts to hum and boom through the vocal mics.

To be honest I live almost exclusively with 2 very important techniques:

Lots of HPF in the right places and good time alignment/phase characteristics of the system.

Other sound guys look at me funny when I take a 6-10db boost at 800Hz with a pretty wide Q on the bass guitar, until they hear it!

[Haysus]

Pay attention to Ron K he is giving you 100% free education that took me years to learn on my own. I run LOUD bands in small clubs all the time with upwards of 8 open mics. I don't use feed back destroyers and I rarely have feedback, even when singers are in front of the speakers.

Also look at Audix OM2 or OM5 mics, worth every penny when it comes to feedback rejection.

Dave Non Zero, I to have just recently heard others talk about this secret. It has really helped my mixes FOH but more important, it clears up stage mixes and reduces the "more me syndrome".

[subharmonic]

Sweet. Thanks for all the advice. I will be mulling it over a bit as it is all a new to me and I am trying to make as much sense as possible.

I do have very little open mic time, but I want to be able to go to the dance floor with a mic for emcee stuff and not have to have someone standing at the board ready to turn it down. Or hand the mic to a guest for a announcement/toast/ or even rap Sir Mix Alot (that one was a disaster, no more karaoke crap, no more guests 3 sheets with the mic)

Lots of HPF in the right places

I need a little clarification on this, so is this notching out the 250/500/3k/5k/10k or whatever my room is demanding, via ringing the system. If it is wouldn't doing the fixed feedback filters on the DBX/Behringer be the same fix?

good time alignment/phase characteristics of the system.

Is this referring to lining up the subs and tops with delays? and maybe a little more info on phase characteristics would help.


Basically my setup has jumped leaps and bounds from the Behringer $60 pack of 3 mics, to a Senny knockoff that just died out for no reason after 3 uses, great feedback rejection when it worked though. Now I am using a Line 6 XDR955 which seemed to clear up a ton of issues. As far as the board I am using it is a American Audio Q-SD.

As for the articulate loud voice..... ....That will be something I have to work on, maybe time to start going to toastmasters or something. My license plate says: MUMBLES for a reason, it is my 1930 mobster alias given to me by my roommates a while back due to no one understanding me a lot of the time.

So it sound like I may need to spend some cash on a mic preamp. Lets hope some of these items will fix the issue before dropping more cash, I would rather buy DR components.

[Dave Non-Zero]

Pay attention to Ron K he is giving you 100% free education that took me years to learn on my own. I run LOUD bands in small clubs all the time with upwards of 8 open mics. I don't use feed back destroyers and I rarely have feedback, even when singers are in front of the speakers.

Also look at Audix OM2 or OM5 mics, worth every penny when it comes to feedback rejection.

Dave Non Zero, I to have just recently heard others talk about this secret. It has really helped my mixes FOH but more important, it clears up stage mixes and reduces the "more me syndrome".

Yeah i want some audix, really dont like sm58s the room i workin is very good acoustically, so feedbackisnt a problem, especially with an LS9 to save soundcheck settings and EQ curves. couldnt live without it. hehe. Good to know others are using the technique.

Lots of HPF in the right places

I need a little clarification on this, so is this notching out the 250/500/3k/5k/10k or whatever my room is demanding, via ringing the system. If it is wouldn't doing the fixed feedback filters on the DBX/Behringer be the same fix?

noits not the same thing. Ron is referring to High Pass filters on the individual channels, tailored to the needs of the intrument on that channel. I HighPass every channel because i have the capabilties on my desk. For example

Instrument HP setting Hz

Kick Drum 50
Snare 100
rack tom 100
floor tom 60
hihats 250

vocals 150-170
bass 60-70
elec guitars 100-120

if your desk only has fixed HI pass at 100hz say, then they should be engaged on almost every channel.

there are exceptions to all these of course. but basically Hipass is your friend.

Ringing out the system with eq cuts is to target the most excitable frequencies in that particular room. a really bad room can mean you will always have difficulty getting the mics up to a loud level, but then the room probably sounds so loud and messy anyway that a lower level is probably desirable!

I count my blessings every gig that i am finally installed in such a sweet sounding room.

[subharmonic]

Darn. Mo money is what I am starting to see, I need some gear to do the HPF and notching. Maybe will have to look at the Behringer Shark again, looks like a new model is coming out.

[Dave Non-Zero]

are you only running one mic? If so, then you dont really need to spend much money on a preamp, you really just need an eq on the mic channel. (and a decent mic) better to use a beat up second hand 58 than a cheap crappy mic. if it needs to look nice then buy a new grill for a fiver.

the shark is a pre and stuff too isnt it? ive never used one, but heard good things.

[Dave Non-Zero]

As for the articulate loud voice..... ....That will be something I have to work on, maybe time to start going to toastmasters or something. My license plate says: MUMBLES for a reason, it is my 1930 mobster alias given to me by my roommates a while back due to no one understanding me a lot of the time.

+lots

it makes all the difference in the world. All soundguys have learned the mantra of saying ONE TWO... for a reason. the sounds and diction required with those sounds helps to determine if any boominess and/or high ringing is about to happen. They also tend to 'put on a voice' when they do it.
Thats basically what you need to do if you want to be heard. develop a 'DJ' voice, that is more powerful and confident than your own. i suppose its like wearing makeup on film.

[subharmonic]

Thats basically what you need to do if you want to be heard. develop a 'DJ' voice, that is more powerful and confident than your own. i suppose its like wearing makeup on film.

LOLs, I was just practicing that on my wife last night. She couldn't hold a straight face but said it didn't really sound bad, just different from the norm. To me it sounded like Casey Kasem. LOLLOLOL

Has any one used the GLS knock offs of the Shure 58s?