Compression - before or after??

[Crayon Boy]

Just a quick simple question. I was just wondering if compression is better applied while recording, or after a proper signal has already been recorded. It seems to me that it might not matter, and I would rather record a good signal and then find the proper level of compression later, but I just wanted to ask the question and see if anyone could provide some insight. Thanks in advance for all responses.

 

[atlas]

I compress all the time to tape, but when I reach for a compressor, I know why I'm doing it, how to get what I'm looking for, and which compressor to use to get that effect. If you don't know what you're doing in a detailed way with a compressor, and don't have a lot of pre-forsight into the mix stage as to what your decision will do (i.e. before the mix actually happens), you could approach it in two ways. Throw it to chance and learn what works or what doesn't work by compressing to tape. If it doesn't work, well you're screwed. If it does, you're a genius. Either way you've learned something at that point. Secondly, you could play it really safe and just compress during mixdown, where you have complete control over the parameters of the compressor before it's printed to the stereo master. Good Luck.

Nathan Eldred
atlasproaudio.com

 

[Crayon Boy]

Captain Obvious

Any particular reason that you compress directly to tape? Is there any advantage to it? I shall now dub you Captain Obvious.

 

[acorec]

Compressing during recording (to TAPE) is a must. But, compressing for effect is not. The tape media is noisy compared to digital. The goal is to record as "hot" as possible to push the noise floor way down. You are trying to prevent clipping and reducing the dynamic range a bit. This way, the tape hiss is largely eliminated. Compression for "effect" is better left for mixdown. This way, you can always undo any track that sounds bad. I always compress going to digital for "effect" because I am so familiar with my equipment and know exactly what I am looking for.

 

[Crayon Boy]

Digital

Ok... I get the point about compressing to tape when recording analog... I am using a digital machine, so any further insight into this would be appreciated.

 

[acorec]

Re: Digital

Ok... I get the point about compressing to tape when recording analog... I am using a digital machine, so any further insight into this would be appreciated.

OK. In the digital world, we have the CD as the final source of a mixed sound (usually). 16 bits are not enough to get a good dynamic range. The resolution is not good enough. I am saying that if you listen to any CD, you will notice that the volume does not really change much. Dynamic range is the difference between the softest passage and the loudest passage of a given recording. There are simply not enough bits in the A/D, D/A converters to accomodate the volume changes. So, the compressor is used to reduce the dynamic range. 16 bits IS enough to get a high quality recording with reduced dynamic range. Today's recordings on CD are very compressed at the recording stage AND the mastering stage. The result is that CDs sound "loud" and "even". If you are recording in 24 bits (or up), this is not a problem. You can have a huge dynamic range. But, eventually you will go to CD or DAT. This is where you will find the problem. Lower volume material will sound "fuzzy" with funny dropouts below a certain level. The main goal of compressing, then, is to keep the dynamic range within certain limits. BTW: This is why loud rock music sounds great on CD. The very nature of the music is loud with reduced dynamic range. Symphony orchestral recodings is where CD is well hated. Symphonic music ia ALL dynamic range from super soft passages to quick loud passages. 16 bit systems mutilate these types of recordings. Those classical guys use vinyl as much as they can.

 

[Robert D]

Crayon - Experimentation is key, but I agree with your first instinct, which is to usually save compression for after tracking. The exception to this general rule is if you have a world class analog compressor to record through, and don't want to go through an extra set of conversions to send the track back out to it aftarwards. But even with a merely good quality analog compressor, there may be times when it's not possible to sing a vocal with the proper range of emotion without going from poor bit resolution in one spot to getting overs in the next. That's when it's time to patch in the compressor. Also, consider limiting, as opposed to compression for tracking. The limiter should be set up as an insurance policy. That is, it should sit there and do nothing most of the time, but save your track from that one or two moments when an over would have ruined it.
Regards, RD

 

[Light]

I do both, for different purpouses, at different times. I also rarely go all the way (compression wise) durring tracking, but leave myself room for adjustment while mixing.


Light

"Cowards can never be moral."
M.K. Gandhi