Audio question - Automatic Gain Control

[ibezdechi]

I usually use my HVX200 for TV news application (TV news packages), but was called on to shoot an evening of standup comics. I used a shotgun mike to record the acts. I really wanted to be able to plug into house sound, but that was not a possibililty.

I was riding gain all night, as some of the comics were kind of soft, while others were very loud at which time I would slowly ride gain.

For this type of application, do you guys think using the Automatic Gain Control would have been a better option? I'm not crazy on how it comes out on the highest peaks, but would this be a good alternative to riding gain?

[Jim Carswell]

Probably not. With automatic gain engaged the camera searches for audio to control- whether up or down. As a result the lowest audio levels in the room would be raised creating unwanted noise during quiet periods of the performance. You would start hearing the rooms lights, air conditioner and other ambient sounds. Your best bet is to always run audio with manual controls. I would advise against usingyour shotgun mic at your camera position for the type of filming you described. Move the mic as close as possible to the performer (hard lined or wireless). This will result in much higher quality sound.

Jim

[Matt Hoss.]

Actually, the AGC doesn't act like a compressor -- it doesn't boost background noise. It's strictly a limiter, it clamps down on peaks.

If you're not hooked into a mixer, leave AGC on and reduce the gain a couple notches on the second channel just in case the AGC doesn't catch a peak fast enough. That way you can use the audio peaks from the second channel as a backup if you need to.

[ibezdechi]

Probably not. With automatic gain engaged the camera searches for audio to control- whether up or down. As a result the lowest audio levels in the room would be raised creating unwanted noise during quiet periods of the performance. You would start hearing the rooms lights, air conditioner and other ambient sounds. Your best bet is to always run audio with manual controls. I would advise against usingyour shotgun mic at your camera position for the type of filming you described. Move the mic as close as possible to the performer (hard lined or wireless). This will result in much higher quality sound.

Jim

Actually what I did was this: I hardlined my shotgun microphone to pick up the PA speaker in front of the stage (I was in back). The audio actually turned out pretty good, overall, but it was those darned loud peaks with one performer which I was really unhappy with, plus the part of doing the manual gain.

Here is a link to the completed video:


http://vimeo.com/45010535

http://vimeo.com/45010536




BTW, the client was ecstatic with my work and has brought me back on. Perhaps I should hardline a regular omni mike instead, and follow Hoss' suggestion?

[Philip Goetz]

I thought that said "romantic gain control"...

[rockett]

I think Hoss has it spot on if you dont have a mixer. Why have the added problems of the house mixer being set up wrongly and clipping through the PA you have little control of the sound you could easily hard wire a mike in this situation id get a mike in the crowd as well if you have a mixer and dont forget the room tone for editing.
I know you started with gain control camera question but if you post this in the Audio section you will get a ton of help in how to improve the sound even if you dont have a good mixer. Hosses idea of lowering the gain on one input sounds like a good back up plan to me but definatley get that PA out of the equation and record from the source not the processed sound and better still borrow a mixer if you can.