View Full Version : Slight ring in lav mic


Steve Hontz
January 24th, 2012, 09:44 AM
I had to film a church service the other day. The pastor already had a wireless mic on him to feed their house system; I added a wireless AT899 a few inches below that (probably about 6" below his collar) to feed my Canon XF305.

The audio from my mic was quite good, but I noticed a slight ring during some of his talking. They had just presented the pastor that day with a brand-new acrylic podium that he was standing in front of the majority of the time he was speaking. Could I be picking up some reflections from that? Would there have been any way to avoid that (say, using a cardiod mic vs the omni AT899)? Is there any way to pull that out in post? I tried EQ'ing out some of the frequencies and it helped in some places and not others.

Richard Crowley
January 24th, 2012, 10:52 AM
Are you saying that the ring wasn't there before the acrylic podium? I wouldn't attempt to guess what could be happening without at least hearing a sample. There are way too many variations and we could be guessing all month.

Kawika Ohumukini
January 24th, 2012, 11:42 AM
Sounds like feedback but it's hard to tell. If you have a spectrum analyzer, see if the ringing is in a narrow band and either EQ it out, which you've tried, or grab a noise sample when he's not talking and use a noise reduction tool with it. GL

Greg Miller
January 25th, 2012, 11:57 AM
Right now I'm wearing a red shirt. Do you think it's too red? Or maybe you think it's more of an orange.

</sarcasm> Sorry...

In other words, I would want to hear a sample before passing judgement on the source.

In general, if it's more of a resonance, the level of which goes up and down exactly when the level of his voice goes up and down, then perhaps it's a coming from the podium... either a reflection or a resonance within the podium itself.

You might go back and try tapping on the podium and see if you can excite a "wolf tone" there. If so, record that, measure the frequency, and dip it out of the file in question. (In that case the podium should be re-designed and re-built to avoid future problems.)

If you don't find a resonance as above, then it might have been a reflection from the podium.

On the other hand, if it's really a "ring" that lasts in time after his direct voice has died down, then it's more likely a feedback ring from the PA system, or some other resonance within the room. How big was the room?

Please post a sample, and you'll probably get some good opinions. Audio only, high bitrate if possible, no video required, should suffice.

Ty Ford
January 27th, 2012, 10:31 PM
I had to film a church service the other day. The pastor already had a wireless mic on him to feed their house system; I added a wireless AT899 a few inches below that (probably about 6" below his collar) to feed my Canon XF305.

The audio from my mic was quite good, but I noticed a slight ring during some of his talking. They had just presented the pastor that day with a brand-new acrylic podium that he was standing in front of the majority of the time he was speaking. Could I be picking up some reflections from that? Would there have been any way to avoid that (say, using a cardiod mic vs the omni AT899)? Is there any way to pull that out in post? I tried EQ'ing out some of the frequencies and it helped in some places and not others.

For any of a dozen reasons, I think you were hearing the house feedback. Nothing you can do about that in your situation.

Not through EQ, but maybe via noise reduction software,

Regards,

Ty Ford