eliminating microphone feedback

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rhedcerulean
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eliminating microphone feedback

Post by rhedcerulean » Fri Jul 20, 2007 12:29 am

Ive read that mic feedback can be EQed out, and that there are plugins that limmit feedback too.

Any tips at all about this would be very helpful.

thnx.
Tomorrow may come, so lets live today.

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Clearscreen
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Post by Clearscreen » Fri Jul 20, 2007 1:46 am

i don't know of any plugins but the behringer shark (http://www.behringer.com/DSP110/index.cfm?lang=eng) is supposed to work pretty well.
Hp Elitebook 2.8Ghz. Live 7.0.14 & Live 8.1.5, XP Pro. and stuff...

rhedcerulean
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Post by rhedcerulean » Fri Jul 20, 2007 4:35 am

Hmm. I knew that I could buy some expensive hard wear. I hope I dont have to.

The obvious first steps are to control the mic trim and monitor location. This is such a basic problem that I figured that Id get good sugestions from my Ableton brothers and sisters. Not that I wount want to know about good hard wear options, its just getting expensive and a pain to bring arround.

Theres got to be a simple inxpensive solution. I just to want to add some live vocorded and or delays to my the downtempo Psy PA act. The monitors seem like they ought to be far enough away from me. The last time did my set I did some live experementation with my Kaoss pad and the mic imput. The set before that, a week earlier, through my Edirol. Its sort of embarrassing. Ofcourse I spent a fair amount of time In my home studio (my spare bed room)experementing. It was a chore there but I figgured I had the kinks worked out and, that I understood the parameters well enough to make what ever adustments I was going to need to make at the venue. Well the sound was alot louder, so I turn the mic trim down right? Still I blaired the feedback squelch several times and couldnt find a happy spot where the vocals were loud enough and the feedback was tamed. Embarrassing. =(

I'll keep looking for stuff on the would wide web. Thanx for any help tat you can offer.
Tomorrow may come, so lets live today.

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Ruso
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Post by Ruso » Fri Jul 20, 2007 6:42 am

easy, use headphones..... if you can't, then the best way is to keep it away from monitors/speakers... there's always a "sweet spot".... put it to the side of the monitors where there's no direct sound going into it.... depending on what you use the mic for you can also eliminate feedback by using effects.... for example a vocoder produces almost no feedback or effects that modify the sound a lot with any effects it will eliminate it for the most part. I guess if you plan on singing into it in a live situation it's more difficult, I had this guy come in and freestyle at my fave club in front of a large crowd and even then there was feedback.


as for effects a decently medium to strong chorus helps with feedback a LOT... some flangers help somewhat....

phasing out one of the channels using abletons utility plugin helps a little but obviously makes it sound weird.


as for eqing I've tried that before and feedback happens on a lot of the frequency bands.... and especially on those bands that are rellevant to vocals so it's not very practical at all.

gating the sound helps a lot for short vocal parts... like saying single words or making sounds.

rhedcerulean
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Post by rhedcerulean » Sat Jul 21, 2007 2:00 pm

Thanx Russo Ill try experementing with those effects.

Ofcourse Ive continued to read the countless articles in this subject that can be found on the internet. I beleive that a directional mic would be the most practal adjustment,(I already have one, I just dont want to be using a compressor mic If I dont have to.) You see I was playing at a venue that Im scheduled to play many more set at. Im right next to a wall, I belive that that sound was reflecting off of wal, thats why it didnt help if I moved the monitors this away or that way, or if I moved the mic here or there. I had this hunch while I was at the venue, so I tried to adjust accordingly.

Most of the advice I picked up from the many articles are basicly teling me to do alot of mic testing before the show. Ofcourse that testing has to be done at the venue at the desired volume. As a DJ I dont allways have that luxury. Hense the need for some software control, i.e. Eq tricks or plugin or an AU.

If there are hardware that detect and process out 'bad fequencys' there ought to be a plugin. I read in one source that there is such a thing, but there wasnt any mention of it name or where I might get such a thing.

Still searching, I want to be prepared.

Thanx for any tips or tricks that might help.
Tomorrow may come, so lets live today.

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Ruso
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Post by Ruso » Sat Jul 21, 2007 6:40 pm

do keep in mind what feedback is has nothing to do with frequencies.... it's the sound entering the mic coming out of the speakers back into the mic(cause there's a tiny delay) and it just stacks and gets louder. this is the same effect actually as plugging a video camera into the tv to see what it's showing and pointing it at the tv, or even the two mirrors reflecting each other.

directional mic is a definite solution but if you got monitors pointing at you and there is a wall behind you like in most cases it's not gonna help much.


Bring along a giant piece of sound insullation and tape it to the wall behind you before your set lol ;)

Michael-SW
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Post by Michael-SW » Sun Jul 22, 2007 12:55 pm

Any pitch shift on the signal (no matter how small) prevents feedback. You don't want that on real vocals of course, but if you are mainly doing "fx style" vocals you could try it.

The Grain Delay can be used as a pich shifter. There is a rack or two that shows how to do it coming with Live 6.

hambone1
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Post by hambone1 » Sun Jul 22, 2007 4:42 pm

Mic and loudspeaker choice and placement, room treatment, subtle use of EQ.

I'd rather cure the cause than the effect.

rhedcerulean
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Post by rhedcerulean » Mon Jul 23, 2007 5:06 pm

Thanx Michael. i like the pitch shift thing, its a nice trick to know.

I agree Hambone, fix the problem not the soultion, its a good defalt way of thinking (Im a life coach.) However, as I mentioned I couldnt do more than I did, and it wasnt getting me the result that I needed.

Its good to fill up your bag with tricks, just in case, no?

Im still holding out for a plugin. Its gotta be out there!!!

I love the tips and tricks that Ive learned, thanx to those who have contributed.

Any more subtilties, tricks or tips lay em' on me. Im soaking em' up!
Tomorrow may come, so lets live today.

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icedsushi
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Post by icedsushi » Mon Jul 23, 2007 7:17 pm

You're not putting compression on the vocals, right? Hopefully not, just double checking.

While it keeps levels under control, it also amplifies anything down near the noise floor. I think compressing live vocals would worsen the situation and bring up the level of the noise causing more feedback...

Michael-SW
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Post by Michael-SW » Mon Jul 23, 2007 8:30 pm

Even a subtle saturator on the master bus has caused me feedback problems. When I removed it, everything was fine.

gavinclarkeuk
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Post by gavinclarkeuk » Mon Jul 23, 2007 9:27 pm

It depends on the size of the monitoring setup and room acoustics. Different approaches will work in different rooms.

Feedback from monitors on larger systems is generally done either using feedback eliminators or with careful use of EQ. The frequencies that tend to feedback are dependent on the room and speaker acoustics. You should be able to use notch filters to knock those stray frequencies out, and enable you to push the volume a bit more.

One other tip is to never put your hand over the microphone if it starts feeding back, as this will often make it worse. In fact you can use this technique (carefully, watch your ears) when sound checking to see which frequencies will feedback first and eq them out ahead of time.

rhedcerulean
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Post by rhedcerulean » Wed Jul 25, 2007 7:03 pm

Thanx again. 8)
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Clearscreen
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Post by Clearscreen » Thu Jul 26, 2007 12:13 am

i experimented with a plogue bidule setup last night that i think was doing the same thing as the behringer shark does (notch filtering of the 12 loudest frequencies - thats what i found out over on kvr anyway...). it was reducing feedback significantly (even though it made the audio sound crap... clearly behringer are doing something differently if it sounds ok) but with simple fft's only finding the two loudest frequencies and notching them out it was running at 25% on my (old) 2Ghz laptop... so maybe thats why no one has built a vst to do that - it eats cpu cycles!! by my calculations to have 12 of em running it'd take around 150% of my CPU!!! DOH! if it was coded properly you could obviously get it running more efficiently and have it sound better, but it'd probably still chew up a fair chunk of cpu.

i could well be wrong though...

i still reckon it'd be worth looking at getting a shark for you - they're pretty cheap on ebay (<$100 US). cheap is always a relative term though...
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kimyo
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Post by kimyo » Mon Jul 30, 2007 7:05 am

we usually play without stage monitors, instead we use headphones/in ears.

there are still issues where the house sound can bleed through.

try putting a gate in front of any other efx, this will kill sound below a certain level and allow you to set volumes higher. also, the best stage mic possible/affordable is worth checking out.

i'd love to hear how artists like imogen heap/that one guy prevent feedback.

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