Slight ring in lav mic at DVinfo.net

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

Quote:

Originally Posted by Steve Hontz

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

January 24th, 2012, 09:44 AM	#1
Steve Hontz New Boot Join Date: Nov 2011 Location: Peoria, Arizona Posts: 22	Slight ring in lav mic 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.

January 24th, 2012, 10:52 AM	#2
Richard Crowley Trustee Join Date: Aug 2007 Location: Portland, Oregon Posts: 1,238	Re: Slight ring in lav mic 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.

January 24th, 2012, 11:42 AM	#3
Kawika Ohumukini Regular Crew Join Date: Oct 2011 Location: San Diego, CA Posts: 185	Re: Slight ring in lav mic 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

January 25th, 2012, 11:57 AM	#4
Greg Miller Trustee Join Date: Jan 2011 Location: Pennsylvania Posts: 1,786	Re: Slight ring in lav mic 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.