Latency with Aux Channel

[doubleyouel]

ok here's the deal: if i set up an audio track to record a mic signal there's no latency in the headphones whatsoever. but if i send the mic signal to an aux channel to compress it then to an audio track there's latency in the headphones. keep in mind that i'm using the headphone jack on the 001. how do i fix this?

[doubleyouel]

ok i just ran a couple tests and it turns out that there is an 8 millisecond delay when recording vocals through an aux channel. is the only way to compress vocals going in while avoiding delay to use an outboard compressor before the mic signal hits the 001?

[valvebrother]

"is the only way to compress vocals going in while avoiding delay to use an outboard compressor before the mic signal hits the 001?"

Yes, that's the only way.

Even when you send the signal to an aux channel (delay or no delay) you are not "compressing on the way in".

If you do not compress your analog signal before it hits the A/D converter, you are not compressing prior to recording. Anything you do to the signal after the A/D process; be in via an aux channel, an insert or audiosuite, should be considered compressing after recording.

[doubleyouel]

on the contrary. sending a mic signal to an aux channel with a compressor on it then bussing that signal to a recordable audio track does compress vocals on the way in. the only problem is that there is a delay because of the aux track (8 milliseconds).

[TAPKAE]

What he was saying is that you are not compressing before conversion to digital, usually the reason for having a compressor inline at all. But maybe you need a sonic stamp on your track? But don't kid yourself. Doing an aux track insert isn't compressing where it will do best-- before the converters.

[doubleyouel]

traditionally, where is the compressor in the recording chain: before or after the mic pre? shouldn't there be some way to compress within pro tools before recording to disk besides this way i am talking about? i have a compressor plug-in, so why should i have to buy an outboard compressor?

[mentalmusic]

Traditionally, the compressor comes between your mic pre and your line-level input of your recording medium (in your example, ProTools.)

What everyone is trying to say is that there's no advantage of recording through a plugin compressor over just recording the track and then compressing it during mixdown.

For example:

Let's say that you're recording a Fender Jazz bass and everytime she hits an open F string (she's tuned up a half step [img]images/icons/wink.gif[/img] ) the recorded signal digitally clips and you get a red light [img]images/icons/mad.gif[/img] on your meter within ProTools.

You could then add a hardware compressor between the mic pre and the input of your box (001,002,or whatever you're using.) The compressor could then be dialed up to level out the bass guitar so that you could still record just as hot of a signal (which is debatably good or not so good [img]images/icons/rolleyes.gif[/img] , but that's a different topic) without clipping and getting nasty digital distortion. [img]images/icons/smile.gif[/img]

The problem with inserting a plugin compressor (like you described above) is that it is being inserted after the A/D conversion. That means that that the signal has already hit the digital domain and clipped. [img]images/icons/shocked.gif[/img]

No good.

Therefore, not only are you recording with extra latency and locked into a compression setting that you could have probably dialed in better during mixdown, but you are compressing an already clipped signal. [img]images/icons/frown.gif[/img]

Don't worry, I used to do it too! [img]images/icons/cool.gif[/img]

[doubleyouel]

an interesting and informative post, mentalmusic. my problem is that my mic pre is on my box, so is it possible to run the mic to the compressor THEN to the mic pre on the 001, or does the signal have to be amplified before hitting the compressor?

[TAPKAE]

A NON preamplified signal is rarely enough to hit a compressor with enough juice to have it do its job. Line level stuff can be put in line with no preamps around, but if you are talking about a mic or DI feed, just bank on it always being a chain of Mic/DI > Pre > Comp > Recorder.

Got it? No more questions on that one, eh? Besides, why would you want to compress a sound before bringing it up to working level?

[doubleyouel]

i always figured that the dynamic range of vocals is so wide that they HAD to be compressed on the way in. theoretically, the more dynamic the signal, the lower the minimum volume level, which is not the best quality audio information.