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Topic: Feedback from Lapel Mic
Message: Posted by: darshwood (Oct 31, 2010 08:01AM)
So, I have been renting lavalier microphones from a local place for all of my large shows. Seems like I can never get away with being loud without producing insane amounts of feedback from the amp!!! Is there any good reference material about creating a sound system... sound systems for dummies or something like that?
Message: Posted by: Dan McLean Jr aka, Magic Roadie (Oct 31, 2010 08:37AM)
Message: Posted by: Michael Messing (Oct 31, 2010 12:44PM)
Dan's site will certainly help. I found that I had to get a unidirectional lavalier mic to avoid big problems with feedback. (It also helps to use a 31-band graphic equalizer to isolate what range is causing the feedback.)

A headset mic is a lot easier to work with. Since I switched to headset mics, I haven't used my equalizer at all. (Anyone want to buy a 31 band equalizer in a case?)
Message: Posted by: darshwood (Oct 31, 2010 03:29PM)
Too cool! Thanks so much, Dan! This is exactly what I was looking for!
Message: Posted by: Balloon&MagicGuy (Oct 31, 2010 08:38PM)
I too had problems with my lapel mic and have switched to a headset. I love my headsets and have had similar success as Michael had shared. I do carry an extra body pack and headset just in case.

Also, all my mics have the sponge tops to assist with wind.

Message: Posted by: robertwong (Nov 1, 2010 09:55AM)
I use a lapel mic for my birthday party shows, however when I do a large stage show with full production, I only use my headset mic.

Message: Posted by: Oliver Ross (Nov 1, 2010 01:28PM)
I'm using a lapel mic and never had problems. It's a SHURE wireless omnidirectional (cardioid) lapel mic and I use it in a room for 100 people. The speakers are standing on tables at a distance of 3m away from me and about 90cm above the floor.
The speakers are aswell a little more in the front stage area and I'm generally standing in their back, except if I'm going into the audience and even then I never have a problem of feedback.

The speakers soundwave is going 30 inside to the center of the room.

The mic receiver is directly fixed on the mixing table without any equalizer.
The lapel is fixed about 20cm beneath my mouth on the shirt.

Maybe you're just pushing the volume level too high...

Anyway Dan's link is a good source to start with.

Message: Posted by: Alan Munro (Nov 2, 2010 07:26AM)
I gave up on lapel mikes, except in venues that have speakers spread throughout the room. If I'm using a portable PA, I'll either use a hyper-cardioid handheld on a Gim-crack holder or a cardioid headset.
Message: Posted by: dmkraig (Nov 3, 2010 03:26PM)
Do a web search for "feedback eliminator." There are "magic" boxes available that should easily solve your problem.
Message: Posted by: silverking (Nov 3, 2010 04:30PM)
They're actually not magic boxes at all......in fact, they're not even smart.

What you're buying is a simple "gain-seeking" circuit that looks at the audio signal,and breaks it down into very steep component bands.

When this (somewhat hit or miss) device does when it see's a rapid build up of gain in a specific frequency is to apply a very steep, and very deep notch filter to that frequency band.
It "assumes" that rapid build up of gain is in fact, feedback......which is not always the case.

It's really no different than using your own ears and a 1/3 octave graphic EQ to pull down a much more gentle, and much more intelligent ('cause it's your own ears and brain) set of frequencies related to the feedback issue being dealt with.

No feedback eliminator will give you even 20% of what you'll get if you read, digest, and follow the advice on Dan's website on [i][b]Speaker Placement and Microphone Selection[/b][/i].
Message: Posted by: rcarmichael (Dec 1, 2010 08:31PM)
Hi darshwood,
Lapels are difficult to work with as they are positioned so far away from the mouth, and thus the gain has to be set pretty high to pick up voice. If you can, a headset is always best - and use a flesh coloured headset, with a smaller microphone, so it isn't as intrussive as the big black "Sham-WOW Commercial" type of unit.
Feedback is caused by sound coming out of the speakers, into the mic, out of the speakers again, into the mic again, and so on. So, it is always best to have the speakers far infront of you rather than to the side, and avoid (if using a lapel) a Sub, as High End is directional, ie it will travel forwards, whereas Bass is Unidirectional, and will go back into the mic - this brings me to my next point - people think only the top end feeds back, when it can really be at any stage of the spectrum. If using a Lapel, it is a neccessity to have an EQ, the more give the better - Graphic EQ's are best. But if you can only get away with a 3 - 4 band EQ, it is still better than nothing. You must listen for the frequency of the feedback you are getting - is it High, Mid-range, or low - and issolate that point. Then remove that frequency using your EQ.
Also, in addition to the above point, if you can get away with it, don't use Foldback with a Lapel, as it shoots straight into the unit.
Learn to project your voice, don't rely on the microphone picking you up - the more you project, the less gain is required, and thus the less feedback you will get.
Lapels are troublesome, and often it is impossible to get it "perfect", but following these tips will allow for a better sound quality, and less chance for feedback!
Sincere regards,