Secondary audio recorder question

[Eric Toline]

Setting one channel lower for safety went out with analog recorders. With digital zero being -20dbfs you have 20db of headroom way more than a padded analog channel could give you.

Eric

[Matt Dufilho]

Thanks for commenting, Eric.

I’m really just worried about a talking head clipping on one of these audio recorders without a second channel protecting me. Are you saying that I should set my levels to average around -20db to be safe?

Can I assume that I won’t be able to run a single mic/source to two channels on a digital recorder?

[Eric Toline]

Setting your reference level to -20 is a very good idea. It’s the accepted professional digital reference standard, peaks should be kept below -10 just to be safe Depending on what recorder your using sending audio to both tracks can be done. Best that you read the manual to find out how to do it.

Eric

[Matt Dufilho]

Thanks for the tip, Eric.

I’ve always shot for -12 as my average, but it sounds like -20 might be my new standard to shoot for…especially if I’m unable to push my mic to two channels.

[Ty Ford]

Hello Matt and welcome to the Cow Audio Forum.

What Eric is referring to is setting tone from your mixer while it is at 0 dB to -20 on your camera.

Most of the analog mixers used in location audio (certainly all of the Sound Devices mixers) work this way. These mixers have usable audio all the way from below 0 to + 20 on the mixer.

The idea is to calibrate 0 on the mixer to -20 on the camera so you don’t have to look at camera meters to know the level you’re sending to it. Usually you want to try to hit peak levels at about -10 on the camera. Because of the 20 dB offset, that means those same levels should be about +10 on the mixer.

Most good, professional mixers these days have limiters that don’t mung up the sound. They can be placed at the mixer input and/or mixer output. Sound Devices puts them at BOTH places, so it’s difficult to overdrive the mixer input or the mixer output to the camera. That, in addition to calibrating the mixer to camera so you’re only hitting peaks of -10 on the camera, means you usually don’t have to lower the gain a little on one track to handle occasional distortion due to loud moments.

Having said that, if there’s a lot of normal talk as well as yelling and screaming and you don’t know when that will happen and you aren’t actively mixing, maybe offsetting record levels isn’t such a bad idea.

Also be advised that limiters on mixers are normally designed for human speech. Quick sounds like handclaps, gunshots and the opening of a three ring binder can sneak past a mixer’s limiters and momentarily clip. If the clip isn’t too severe, you’re usually OK.

Regards,

Ty Ford

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