Dual Mono v Stereo Compression

[Mixxed Up]

Is it critical or necessary to link compressor channels? I have read other threads, specifically about the drawmer 1968-69 on mix buss. Seems some are using these units in dual mono mode and getting good results...

Why / why not link the channels (or two mono units) of a stereo compressor? esp when recording stereo material.

Are there any benefits to either method?

[Kiwiburger]

It depends on how much variation you have been left and right.

Imagine you have kick, snare & lead vocal panned Centre. Imagine you have a floor tom, for example, panned hard Left that is fairly loud and peaky. What happens when the floor tom is hit? The left compressor channel reacts to the peak, and drops the gain for the whole left hand side. Unlinked, the right channel compressor doesn't, and remains at the same gain.

The result is that the whole mix gets softer on the left hand side, which basically means the whole mix lurches to the right.

That's why stereo link is offered. But if you mix is fairly unadventurous, this may never be an issue. You might benefit from a slightly more open mix if you remain unlinked. Options are handy.

You can achieve the stereo linked effect out of dual mono compressors if you use the side chain. Create a mono mix of the two channels, and route that to the side chain of both compressors.

[u b k]

Originally Posted by Kiwiburger

The result is that the whole mix gets softer on the left hand side, which basically means the whole mix lurches to the right.

you'd have to be mixing that hard-panned element rather zealously, into a comp that's compressing intensely, to get a mix to lurch anywhere. not that it can't be done, it's just an example of bad driving.

in practice, what generally happens is that whatever element you are pushing ducks the rest of the mix on that side, but the element itself maintains the energy of that part of the soundfield; the fact that the energy remains balanced mitigates what would otherwise be an unstable center. the thing hits 10 degrees left, everything else shifts 10 degrees right, the whole thing is usually over in a few hundred milliseconds.

as long as you're doing things with a skilled ear it won't make you seasick, it won't even be noticeable for what it is. it'll just sound wider than if you have both channels linked.

one of the features i love about the api2500 is its variable link; you can go dual mono, or anywhere from 50-100% correlation. i like to keep it on 60%, it's a great balance of the extremes.


gregoire
del ubik

[norman_nomad]

Originally Posted by Mixxed Up

Why / why not link the channels (or two mono units) of a stereo compressor? esp when recording stereo material.

Why: Like Kiwi said, you'll get equal gain reduction over the stereo field, and avoid image shift.

Why not: More interesting results. Sometimes a larger sounding stereo spread. To be a rebel. (kidding).

Linking a stereo compressor may be more necessary in the event that the components between the two are not well matched.

In my DIY dual 1176, I almost never use the link feature on stereo material. I carefully matched the FET’s (responsible for gain reduction) between units and they track very similarly.

I think I remember someone saying that Michael Brauer uses a lot of his compressors in dual mono…

[Mixxed Up]

understand... and thanx!

so if tracking an acoustic guitar or guitar amplifier in stereo (or via 2 mic's) or maybe piano/keys w/amplifier, if may be beneficial to remain unlinked, in dual mono mode?

I've never tried this yet, mostly due to not wanting to f*ck up the final mix, down the line.

Has anybody done this tracking instruments with good or bad results? Are there any hard-fast rules?

btw- When tracking an instrument with 2-mic's and linked compression, I always record to a stereo track. Would you record to 2-mono tracks if using the compressor in dual mono mode?

[Kiwiburger]

If the signal is basically identical - e.g. a single keyboard or guitar, then the difference between channels will just be small differences in room sound, and both should peak in the same places. So I don't think it would matter either way.

The advantage of dual mono is that you can track two wildly different instruments - maybe a DI bass and DI guitar at the same time.

Some stereo linked compressors aren't capable of dual mono - they have two channels, but only one sidechain.

[norman_nomad]

Originally Posted by Mixxed Up

so if tracking an acoustic guitar or guitar amplifier in stereo (or via 2 mic's) or maybe piano/keys w/amplifier, if may be beneficial to remain unlinked, in dual mono mode?

Not necessarily. Just audition linked and dual mono and go with what sounds best. Generally I stem stereo tracks to my outboard compressors and record them back in on a stereo track. No need to record back to two mono tracks unless you want pan flexibility between channels. No hard rules.

[squeegybug]

Originally Posted by Mixxed Up

so if tracking an acoustic guitar or guitar amplifier in stereo (or via 2 mic's) or maybe piano/keys w/amplifier, if may be beneficial to remain unlinked, in dual mono mode?

Has anybody done this tracking instruments with good or bad results? Are there any hard-fast rules?

btw- When tracking an instrument with 2-mic's and linked compression, I always record to a stereo track. Would you record to 2-mono tracks if using the compressor in dual mono mode?

The sky is the limit. I mostly record acoustic instruments, and mentioned this dual-mono method on that Drawmer thread. Even though I don't use a lot of compression, I can usually feel a little more open, looser mood. Makes it less formal, or something. And of course, can preserve a little more treble with typical stereo mics on acoustic guitars, etc.

I usually record a single instrument to 2 mono tracks and EQ and pan them a little differently to get the fit I want around the vocals. IMO, more freedom = good.

Steve

[Mixxed Up]

Originally Posted by squeegybug

I usually record a single instrument to 2 mono tracks and EQ and pan them a little differently to get the fit I want around the vocals. IMO, more freedom = good.

Steve

Now that makes alot of sense! Seems like this would create a sort of "hybrid" stereo track, based on the 2 mono tracks...

I was always thinking in terms of stereo tracks when using the 2-mic method. Probably limiting myself, to some degree. I'll give this method a try.

btw- It was my understanding that there is a BIG difference between recording and then mixing mono tracks as compared to recording and mixing stereo tracks (or possibly a combination thereof). Is this the case?

I generally try for a combination of both stereo tracks and mono tracks in my work, but have never used the dual mono method in combination with other tracks, within a single song...

[Jay Kahrs]

Originally Posted by Mixxed Up

btw- It was my understanding that there is a BIG difference between recording and then mixing mono tracks as compared to recording and mixing stereo tracks (or possibly a combination thereof). Is this the case?

Unless I'm missing something in the question I don't see any real difference at all.

Stereo & mono tracks are usually mixed together...the simplest example I can think of is stereo overheads from the kit & a mono lead vocal right?

That's gotta be on like, oh say...60% or better of whatever's out there and about 95% of whatever's been released in the last few years.

I always try both linked & unliked compression on all sources including the mix buss for each & every application. Sometimes unlinked sounds a little bigger & better to me & sometimes I can't even detect a difference. It always depends on what's going on within the song.

[lefthando]

Unlinked compressors on a close mic'd piano might give interesting results.

[Nutmeg II.]

Wile there is realy a good reason (or two) to link comps you might still remember that WAY back in recording history the AEs used tape to record the music to.
And one thing is for sure, you cant link tape tracks like comps and it sounded great just like it was, even when you did hit it hard!

[AllAboutTone]

This is a very interesting issue of either using link or daul mono, i have did test after test after test (using 2 buss mix) and my mixes are best in the stereo mode link, my kick sounds better, the bass is a lot tighter in the mix (glue just moldes better in stereo mode)
if you put on headphones in the dual mono mode you can hear the difference, yes my low end seems to wiggle slighly from left to right in dual mono mode (NOT GOOD) etc.....

I repect the last thread about using tape machines and they are dual mono, but gosh look at the width that a tape machines give on both channels, thats why you cannot hear it when you are mixing to tape, Stereo compressors cannot keep up with a 15/30ips 2 track tape deck.

my vote is stereo mode for my purpose. using a Avalon ad2044 bus mix

[heathen]

This all really depends on what type of compressor you have, my pendulum es8 I'll usually run it in stereo mode as I've only ever noticed a very small difference between dual mono and stereo with that unit. Where as my Smart C2 I've hardly ever run in stereo mode as the stereo material does become more narrow when linked, same with my buzz soc 1.1 but no where near as noticeable as the c2. So it is mostly all in the design of the units.