Rescuing audio from High Gain

[editmon]

I recently shot my nephews wedding using a wireless mic attached to my Canon HF100 camera. I tested the mic before the service and again after the church tech dropped the dreaded second wireless mic on me at the last minute. Tested both mics turned on and attached to the minister everything fine until he began vows. Upon his moving at a certain angles, "shifting" I would get a loud "pop" followed by loss of signal then it would re-appear, on and off. I had a zoom H4 as back up but made another stupid error forgetting to check gain setting on the mics. Friend had borrowed the unit at set gain to low. I got a recording from it that is faint and can get audio although increasing gain high enough produces too much hiss and noise. Yes, I should have listened to the little voice saying jack the zoom into house amp and record, but alas, I didn't. Trying to save the day by cutting noise. I know, garbage in, garbage out.
Any advice on recovery of the voice appreciated and any advice on avoiding "pop" and drop on wireless on next family nightmare. Have used Audacity for awhile recording from records but not much experience with gain issues. Much thanks in advance for any help.

[Gale Andrews]

You can try Noise Removal on the hiss. Effect > Compressor might help too.



Gale

[kozikowski]

Only the Pop is the error. Microphone systems like this have a very gentle auto gain system and for the most part it's invisible. However, when the microphone misbehaves or possibly rubs up against something that creates noise, the Auto Gain system goes into overdrive and reduces the gain of the channel. So that's the Pop and missing dialog until the gain system slowly recovers. That part is normal. The pop is broken.

The transmitter part of a radio mic is the failure point -- particularly where the microphone plugs into the unit. I've seen transmitter systems where the manufacturer left off the connector because it was such a pain to deal with. That connection goes away when the performer sits down on the unit, backs into a door, drops it, etc.

Most audio techs would rather open a vein than use radio microphones on critical shows. We've all been burned. My personal nightmare was a radio microphone that turned to peanut butter when our president tried to address the company. It worked perfectly before and after the show (I took it out of rotation and manfully resisted the urge to set it on fire.).

So your only show left is low, noisy, and has hiss. What could go wrong?<g>

I don't know that I would use the compressor tools. Those will reduce the difference between the good sound and the background noise. I think I'd first Amplify to, say, -3dB or so to give you something to work with without getting too close to overload.

Be Very Careful how you capture the profile or "sample" of the noise. The Noise Reduction System will use that sample to root out the noise from the show. If you capture a little voice by accident, NR will try to remove that voice.

If the hiss is really a problem, you can try the Low Pass Filter progressively lower starting with 10,000 and working down. 8000, 6000. The show will get "duller" sounding, but the hiss level will become a lot less annoying.

If the interfering sound other than Hiss is voices, conversation, and people moving around, they may now be permanent parts of the show. Noise Reduction only works with sounds that are constant through the whole show -- like air conditioning and some hiss and buzz. Noise Reduction is designed to drop out during spoken words to avoid Martian Speak, so the best you may be able to do is a good, quiet processional and recessional, but noisy "I Do."

It's classic advertising. The outside of the package looks a lot better than the actual performance of the product. Audacity 1.3.13 Noise Reduction is New!!! and Improved!!! over the one in Audacity 1.2, but it's still not a magic wand.

Koz

[editmon]

Only the Pop is the error. Microphone systems like this have a very gentle auto gain system and for the most part it's invisible. However, when the microphone misbehaves or possibly rubs up against something that creates noise, the Auto Gain system goes into overdrive and reduces the gain of the channel. So that's the Pop and missing dialog until the gain system slowly recovers. That part is normal. The pop is broken.

The transmitter part of a radio mic is the failure point -- particularly where the microphone plugs into the unit. I've seen transmitter systems where the manufacturer left off the connector because it was such a pain to deal with. That connection goes away when the performer sits down on the unit, backs into a door, drops it, etc.

Most audio techs would rather open a vein than use radio microphones on critical shows. We've all been burned. My personal nightmare was a radio microphone that turned to peanut butter when our president tried to address the company. It worked perfectly before and after the show (I took it out of rotation and manfully resisted the urge to set it on fire.).

So your only show left is low, noisy, and has hiss. What could go wrong?<g>

I don't know that I would use the compressor tools. Those will reduce the difference between the good sound and the background noise. I think I'd first Amplify to, say, -3dB or so to give you something to work with without getting too close to overload.

Be Very Careful how you capture the profile or "sample" of the noise. The Noise Reduction System will use that sample to root out the noise from the show. If you capture a little voice by accident, NR will try to remove that voice.

If the hiss is really a problem, you can try the Low Pass Filter progressively lower starting with 10,000 and working down. 8000, 6000. The show will get "duller" sounding, but the hiss level will become a lot less annoying.

If the interfering sound other than Hiss is voices, conversation, and people moving around, they may now be permanent parts of the show. Noise Reduction only works with sounds that are constant through the whole show -- like air conditioning and some hiss and buzz. Noise Reduction is designed to drop out during spoken words to avoid Martian Speak, so the best you may be able to do is a good, quiet processional and recessional, but noisy "I Do."

It's classic advertising. The outside of the package looks a lot better than the actual performance of the product. Audacity 1.3.13 Noise Reduction is New!!! and Improved!!! over the one in Audacity 1.2, but it's still not a magic wand.

Koz

Thanks for the reply! As I said I am NO audio expert but you can rest assured I'll try be before this is over! I am still trying to wrap my head around this reply and a friend of mine who is into audio like a freak told me to copy the file and invert it and make a notch. Uh, yeah ... so he is going to make an effort to bail my sorry butt out of this mess. He was wondering if there is a way (plugin) maybe to view changes in playback of the file on an eq to to "see" the change? Ah yes the blind leading a pro. What more could you ask for. Any take on this question? I hope one day I can return all this help from the forum myself.
Many thanks to you and others so far!

[kozikowski]

make a notch

That's an interesting post. Since he's heard the work and we haven't.

gain high enough produces too much hiss and noise.

That's from the original post. A lot is riding on "and noise." Hiss is straightforward although a little science-fictiony. Microphone signals, particularly at a church are stunningly small. Specialized amplifiers are used to amplify microphone signals to the point that they become useful for editing or production. All amplifiers have internal noise. The object is to make the noise a lot lower than the microphone signal so when you bring them both up, you get singing and not hissing. Your setting of the Zoom reduced the level of the microphone so it's the same size as the natural noise in the system.

All that's old news -- along with the pop. Noise is a Big Deal. What does the other noise sound like? Can you grab some of it -- two or three seconds and post it here? Pick a word or two and then room noise........... I was just about to tell you to do something you can't do. Are you really using Audacity 1.2? The sound rescue tools in Audacity 1.3.13 are a lot better than the older ones in Audacity 1.2. You can put both versions on your machine without interference. Highly recommended.


Audacity 1.2 is very old and no longer supported,
patched, corrected, or updated. Audacity 1.2 can
be unstable on newer computers.

Download and install the latest Audacity 1.3 from here...

http://audacityteam.org/download/

You can install both audacity 1.2 and Audacity 1.3 on
the same computer, but only use one at a time.

Audacity 1.2 will not open projects made on Audacity 1.3.

If you use MP3 or some of the more modern audio
compression formats, get Lame and FFMpeg software
from the same web site. Do not use older software
or software from other web sites, even though they
may have the same names.

Koz

[editmon]

make a notch

That's an interesting post. Since he's heard the work and we haven't.

Actually, he hasn't heard it yet he was speculating based on what I told him. Then he started about the notch and I went deer in headlights on him. So he is coming by to check out what it really sounds like.

gain high enough produces too much hiss and noise.

That's from the original post. A lot is riding on "and noise." Hiss is straightforward although a little science-fictiony. Microphone signals, particularly at a church are stunningly small. Specialized amplifiers are used to amplify microphone signals to the point that they become useful for editing or production. All amplifiers have internal noise. The object is to make the noise a lot lower than the microphone signal so when you bring them both up, you get singing and not hissing. Your setting of the Zoom reduced the level of the microphone so it's the same size as the natural noise in the system.

All that's old news -- along with the pop. Noise is a Big Deal. What does the other noise sound like? Can you grab some of it -- two or three seconds and post it here? Pick a word or two and then room noise........... I was just about to tell you to do something you can't do. Are you really using Audacity 1.2? The sound rescue tools in Audacity 1.3.13 are a lot better than the older ones in Audacity 1.2. You can put both versions on your machine without interference. Highly recommended.

My apologies about not sending a sample. I forgot to bring the file with me today and cut a sample. "makes a big difference when you give someone something to work with"

I do have 1.3.13 beta and Lame from the same link. It will be tomorrow before I can send sample, live 40 miles from work and no internet at home in the middle of nowhere. Refuse to use dial up! I don't know if this helps I am using Win 7 64 premium, quad 6450 with 8 gig ram. I am also going to check the mike and cable for shorts as the unit was borrowed from me by a commercial service and it didn't dawn on me to check it over carefully before using it! Unfortunately I recorded in MP3 format from the zoom h4 instead of uncompressed, probably adding to my problems. Lessons the hard way. I want to thank you again for all the help so far.

Finally got the file to office.
First on has the highest volume followed by small section of "silence" no speakers, and start of vows.
Second clip will follow ... has part of the vows with audio from all three people, groom, bride, and clergy.
Let me know if this helps in solving problems. I notice most of the audio seems to be on one channel and some of the noise was the honking big AC unit just behind the zoom rear right. I knew there was another noise besides gain increase!

zoom_clip_001.mp3

(613.09 KiB) Downloaded 282 times

[editmon]

Second clip of audio

zoom_clip_002_Vows.mp3

(717.17 KiB) Downloaded 335 times

[steve]

Second clip of audio

There's not a great deal you can do with that as the noise level is so high relative to the voices. You could use the Equalizer effect (use the "Draw curves" option) to remove frequencies below about 300 Hz and above about 5000 Hz, then use the Noise Removal effect. It will make some improvement, but not a lot.

[editmon]

Second clip of audio

There's not a great deal you can do with that as the noise level is so high relative to the voices. You could use the Equalizer effect (use the "Draw curves" option) to remove frequencies below about 300 Hz and above about 5000 Hz, then use the Noise Removal effect. It will make some improvement, but not a lot.

If it gets by that's the best I can hope for. Thanks for the advice.