Help me fix this audio mess

smhontz wrote on 9/18/2004, 10:20 AM
(Posted to this forum because I know it'll get looked at more here...)

Background (so you'll understand the mess):
I am a member of a church video team using modest (i.e. cheap) equipment. Recently we were asked to do a three-camera shoot of three of our pastors in an interview setting. We used two Sony D8 cameras (auto white balance only, no manual audio controls) and a Pansonic DV camera. In the past we've only had to mic two people at a time, so we use two ATR35s mics into a Studio 1 XLR BP Pro box into the Sony D8 camera. This gives us good audio with low noise. This time, since we had three people to mic, we had to put the mics into a mixer. The regular portable church mixer was missing, so our audio guy ran out right before the shoot and got us a Behringer UB1622FX-Pro. We also borrowed a single wireless mic. So we had the wireless going into the XLR jack of channel 1 of the mixer, and then, because the ATR35s are 1/8", we used 1/8 to 1/4" adapters to plug them into the line-in jacks of channels 2 and 3. We couldn't get a good signal out the mixer so we ended up coming out of the mixer headphone jack into the input of the Studio 1 into one of the cameras. All of this was rushed because by now the pastors had showed up and we had to get started. Then our audio guy had to leave and I ended up having to work 2 cameras while trying to figure out the audio stuff too. It didn't sound right (I was monitoring from the headphone jack of the camera) - "edge" on the wireless mic and a lot of hiss on the other mics but I couldn't really do anything about it.

Oh, and then during the shoot the air conditioner kept kicking on and off, which was picked up nicely by the mics. Then a front loader proceeded to dump dirt by the building and backed up (Beep! Beep!) several times. Then the church bell chimed several times. Then someone (twice!) tried to come in the locked door (rattling it several times) despite the hot pink signs on every door advising that a shoot was in progress.

So: for now - since I can't reshoot - what's the best way to clean up my audio mess? I have NR2, but I have these questions:
1. Should I apply some EQ BEFORE applying NR? I.E., get rid of some of the low-end rumble and some of the high-end hiss?
2. Should I apply some sort of compression BEFORE NR? I've got some signals that are too hot in places.
3. I've heard people suggest applying multiple passes of NR with small amounts of reduction each time. By that, do you mean, say, adding the NR filter 6 times to a particular track, and reducing by, say, 8 db each time? Or do you mean apply once, render to new track, then repeat?
4. I split the audio into 6 tracks - each pastor talking when the a/c was on and when it was off. I figure I need to apply different noise reduction to each. Does that make sense?

For the future: I've since sat down with the mixer and figured out how it works. I think the biggest issue was the AT35s's going in the line-in jacks instead of the mic-in jacks. (That, plus an FX processor in the loop that shouldn't have been.) Since the mics produce mic level signals, I had to crank the gain way up (hence hiss). Can I get a 1/4" to XLR adapter so I can go ATR35s (1/8") - 1/8" to 1/4" adaptor - 1/4" to XLR - to mixer to get the proper mic level inputs?

I think the secondary issue is that the D8 camera has AGC on the mic-in so when things get quiet you hear it pump up the gain (with more hiss) and then when someone talks it quiets down again. Can't do anything about that now, I guess, but we are saving up to buy a nicer camera (maybe a GL2) so that should help.


Spot|DSE wrote on 9/18/2004, 10:29 AM
the secondary issue is that the D8 camera has AGC on the mic-in so when things get quiet you hear it pump up the gain (with more hiss) and then when someone talks it quiets down again.

Thats a primary issue there...
You've got a lot of issues to tackle.
First thing is edit beeps, front loaders, etc. get rid of them as best you can.
render a new file.
NR first. Normally NR is last. your case is different.
If you'd like to send me a 15 second sample of the worse case, I'll see what can be done in a few minutes, and send you a veg. This is MUCH better to do in Forge though.
smhontz wrote on 9/18/2004, 10:59 AM
Thank you for the generous offer, Spot. Where should I send the sample? I clicked on your name, but it shows me all your recent posts - didn't it used to show a person's profile (and hence their e-mail address) when you click on their name?

I do have Sound Forge 6.0, if that makes a difference on how I should approach this.

Spot|DSE wrote on 9/18/2004, 1:38 PM
dse (at) sundancemediagroup dot com
farss wrote on 9/18/2004, 2:35 PM
As you had 3 cameras that's 6 audio tracks that could have been recorded. With a bit of care you probably didn't need the mixer in the loop at all. Maybe others have a different view to me but for a live recording avoiding mixing is a good move unless you've got a full time sound guy who'se doing nothing else. Having one track per mic makes it so much less prone to things going wrong and way easier to fix in post. Same goes for vision, I've been asked several times to fix both audio and video stuff ups and both would have been easily fixable if tapes were rolling in all the cameras as well as having a live switched tape.
There's probably not much wrong with the images coming out of the three cameras that you used and if you're on a tight budget why not get a sound card / box that'll take say 4 or more mic ins and record the audio straight to HD using Vegas. Given what you're doing I'd be spending my money on that rather than a new camera.
In fact for what you're doing I'd seriously consider selling the cameras to buy decent sound gear if you're really pushed for money, talking heads aren't that rivetting to look at and can easily be replaced with what can be taken with a cheap still camera. Unless I'm mistaken none of the message is being conveyed in the image, it's all in what's said so that's where your priority should lie. The images are just there to light up that box between between the speakers!

smhontz wrote on 9/18/2004, 3:30 PM
Normally we are doing two-camera kinds of shoots, with only two people to film. So, I usually put the Studio 1 box with the two lav mics feeding it, split into two channels, into one camera, and then mount a shotgun mic on the other camera as a backup. This has served us well in the past.

In this shoot, I suppose I could have sent a diferent mic to each camera and sorted it out later. But, I figured if I could send them all into a mixer, I could tweak them all at once, and get a good feed to one camera, and use the shotgun mic again, as a backup, on the other camera. (The third camera just used the on-camera mic, which wasn't very good.)

The problem lay in not being prepared - if I had the mixer the night before, I would have tried everything out and worked out the issues before arriving on set. But I didn't know we would be getting a brand-new mixer right before the shoot, and then I ran out of time to experiment. I should have had the guts to make everyone wait whilst I sorted things out, but I didn't.

As far as shooting stills vs video, especially for talking head stuff, sometimes we (the video team) get to make suggestions as to how we think a project should go, sometimes we just get told what they want to see and we shoot it. Either way, it's always interesting...
farss wrote on 9/18/2004, 11:23 PM
You raise an interesting point. When you're actually 'the show' then you've got to stay in charge. There's absolutely NO point letting the show go on if you're not 110% certain everythings OK cause I'd put good money on it not being right.
This is one of the hardest lessons I had to learn. I'd never understood how guys who were pretty clueless managed to stay in the game and the answer is because when they say jump they can make everyone jump. I've had a fair bit of work from a local Chinese ministry for just this reason, they'd bring in some VIP from OS and they'd be too humble to tell him things like his bald head was too shiny for the cameras or whatever or to stop the show until THAT woman down the back took the crying baby outside.
I guess it's a bit easier for me as I've no religious affilliations, I'm just there to get the job done and I've learned you've got to be pretty bloody minded about it because if you're not even in your situation you can end up wasting everyones time.

Opampman wrote on 9/19/2004, 9:14 AM
smhontz - If you want to send me a short clip I'll be glad to see what can be done. I've got some restoration programs intended for forensics use that will really dig the audio out of noise.