clipping and compression of vocals

[jbraly]

Has anyone found a way to limit the level of vocals at the time they are being recorded? I often clip when I record a vocal, especially if the singer is not good with microphone technique.

I had the idea that you could put the RTAS compressor in Pro Tools Free into the channel and it would work while you were recording. Say, set the ration to 4 to 1 or so, attack at 11 milliseconds, release at 50 ms. Then, if the singer shouts, the compressor would knock it down BEFORE it clipped and you would have a no-clip recording. Alas, the compressor does not seem to work that way -- before the fact.

Perhaps I am setting it up wrong. Anyone have some advice? Do I need an outboard compressor to accomplish this?

Thanks,
Jim

[JHarris]

Hi Jim
to compress a vocal while tracking, you need to create an aux track for your input, and bus the output of your aux track to the input of the audio track you're recording to. Insert a compressor, (or other signal processing) on one of the aux track's inserts. Record enable your audio track, and you should see level going to both channels at this point. Now when you record, your input is routed through the compressor (or other processor) on the aux channel before going to 'tape'.

[M.Brane]

John is correct. You need to run the compressor before your input otherwise your still going to be clipping your hardware.

[audiaudio]

Two suggestions:

1. Use a hardware compressor before the A|D converter. The Avalon 737 is a commonly used mic pre/eq/compressor in one box.

2. Lower the record level. At 24-bit, there's no reason to record peaks anywhere near digital maximum. The mix bus will also benefit from lower record levels.

[John Link]

Originally posted by audiaudio:
The mix bus will also benefit from lower record levels.

What do you mean by this?

John Link

[M.Brane]

I'd like to know how to record into PTF at 24bit. [img]images/icons/confused.gif[/img]

[John Link]

What John Harris suggests may compress the vocal but it will not avoid digital clipping, since the signal is already too strong by the time Pro Tools gets it. The compressor has to be further back in the signal path.

I raised a similar question recently and you might find the discussion useful: http://duc.digidesign.com/cgi-bin/ub...;f=35;t=000940

John Link

[John Link]

Wouldn't we all!

John Link

[audiaudio]

Originally posted by M.Brane:
I'd like to know how to record into PTF at 24bit.

Any of these audio interfaces will enable 24-bit recording into PT Free:

Digigram VX Pocket (PCMCIA)
Edirol UA-5 (USB)
Ego Systems U2A (USB)
eMagic EMI 2|6 (USB)
Sound Devices USBPre (USB)
Tascam US-428 (USB)

[John Link]

audioaudio, have YOU recorded into PTF at 24 bits? My understanding is that PTF takes its sound input only from the Mac Sound Manager, which works only at 16 bits, making recording into PTF at 24 impossible.

John Link