Parallel Multiband Compression for Mastering in Logic Pro

[Lagerfeldt]

How to setup Logic Pro
Follow the instructions to the letter and things will work perfectly.

First you need to make sure full plug-in delay compensation is enabled in Logic Pro. If you don't do this you could get phase problems.

Logic Pro > Preferences > Audio>General > Plug-in Delay > Compensation > All

You need
1 audio track
1 aux channel
1 main output (entitled Output 1-2)

Take a look at the screenshot for reference.



How to do it
Place the stereo mix file you are about to master on the audio track.

Open a send from the audio channel to Bus 1, and send unity value (0.0 dB). The shortcut for this is Option+clicking on the send knob.

This automatically creates a Aux 1 channel with Bus 1 as input, if it isn't already created in your setup.

Now apply whatever mastering plug-ins you need such as equalizer and single band compression to your audio track, not the Aux. However, do not apply a limiter to the audio track and do not touch the volume fader on this track unless you first set send mode to pre-send instead of the default post-send.

If you wish to use a limiter plug-in it should be inserted on Output 1-2 as this is where the processed signal and the parallel signal will meet up, and they need to be processed together.

Open the Logic Multipressor (or a Waves Phase Linear Multiband compressor, though Logic's will do just fine) on Aux 1 and load this preset:
http://www.popmusic.dk/download/logi...ltipressor.zip

Place the downloaded preset here:
HD > Users > YourUserName > Library > Application Support > Logic > Plug-In Settings > Multipressor

Settings
Threshold
-48 dBFS or lower

During this type of compression you need constant gain reduction and you want the compressor to react to very low passages.

Ratio: 2:1
The ratio should be fairly low although you can certainly experiment with this parameter for more radical effects.

Peak/RMS
0 ms

Part of this trick is to violently smack down on transients so you need the compressor to react to peaks.

Attack
0 ms

Same reason as above.

Release
300 ms or above

Too short and things will start to pump a bit which isn't what you normally want. So use release times between 300 and up to a few seconds even.

Shorter release times = more obvious compression but also more effect (especially in the high frequencies)

Longer release times = less obvious compression but also less effect

You can set individual release times per band, i.e. longer release times for the sub frequencies and very high frequencies. High frequencies jumping around isn't as much an issue with the Logic Multipressor but more an issue with 5 band compressors like the Waves Linear Phase Multiband where the ultra high frequencies have their own band (11 kHz+).

Gain Make-up per band
As a starting point you don't need to touch the individual make-up gains. But if you feel the parallel signal needs to contribute more to a special frequency area this is the place to do it. As you're raising a heavily compressed signal in a specific band it sounds very different to equalizing and is a great alternative solution.

Other functions
Do not use autogain or touch the expander. Lookahead isn't necessary for this trick so you can set it for 0 ms (you need to start/stop the song to reset the delay compensation caused by the lookahead if you touch it during playback).

Amount of parallel signal
Use the Aux 1 volume fader to choose the amount of parallel multiband compressed signal you want to add to the blend. A normal setting would be about 15-25% of the original signal but always use your ears.

How to do fades or change the volume
As mentioned earlier: do not touch the volume fader on the audio track as this will affect the input dynamics of the parallel signal. If you for some reason want to adjust this channel then set send mode to pre-send first.

If you wish to do a fade in or out on your master, then do this by automating the volume parameter on the Output 1-2 fader which contains both the original processed signal and the parallel signal.

What is parallel compression
Parallel compression is often used during mixing to fatten up tracks, especially drums. It can also be used on vocals to increase fullness and bring up details without the pumping artifacts of regular (downward) compression.

Parallel compression is also used during mastering since it - unlike regular compression - can raise low level passages while still retaining more of the original dynamics during loud passages. Just as in mixing parallel compression can help fatten up a master and bring up "buried" details.

Parallel compression is not a substitute for normal downward compression but something to use in addition to add fullness and details.

Search the internet for more information about what parallel compression is and how it works in details.

Parallel Multiband Compression
Parallel multiband compression applies the exact same principles as its single band cousin. However, it sounds a bit different due to the separate bands. Parallel multiband compression also acts a bit like an intelligent loudness enhancer because of the psychoacoustics in how the human brain interprets especially the low and high frequency bands in relation to loudness perception. This trick is not possible in the same way with single band parallel compression, even when used in combination with an equalizer.

[userofgear]

hello,

nice to see helpful posts. thanks for spending the time on that.

good going.

userofgear

[SoundEng1]

Thanks!

[smoke]

This seems to be a safer method of MB compression. Very nice.

Why not use sends though?

Also, you should add this to the tips & tricks section!

[Lagerfeldt]

Originally Posted by smoke

This seems to be a safer method of MB compression. Very nice.

Why not use sends though?

Also, you should add this to the tips & tricks section!

I've updated my post so it now uses the best and easiest way of doing things, thanks.

I suppose a moderator could move this to the tips & tricks section.

[A440]

Thankyou for that.

[smoke]

Originally Posted by Lagerfeldt

Actually I might be wrong about this as Logic's pre send isn't pre processing send. Hold on, I'll check that tomorrow and update the post.

This has no influence on the above setup which works perfectly. I'm just checking to see if another (easier) configuration is possible.

On Cubase I believe you have both options, with pre having a 'send amount', in which case control of the amount driven into the aux. (I also have to double check this)

yeah I suggest tips & tricks before this ends up on page 2 where no one would see it, unless they... *cringe* searched.

[Lagerfeldt]

Okay, I updated the post.

This is the easiest way of doing things now. Sorry for the confusion.

As long as you don't touch the audio track fader you will be just find using the default send (post send).

[Lorddiagram]

thanks - nice tutorial and will try it this weekend.

lD

[badhorsie777]

Hey - I'm wondering if you wouldn't mind posting the exact settings, especially crossover points on the bands, as I am using logic express and want to play around with this concept. I have "slimslowslider's C3 multiband comp" - a free and nice sounding multiband... I set the settings you mentioned and got a REALLY squashed sound - how many db do you look to compress on this aux send channel? with -48 threshold, I was getting meter-pegging compressed fizz, so I assume -48 isn't a hard and fast rule - so how many db do you look to compress with your example, and the crossover points, if you don't mind.

Thanks a ton for what you add here - your ssl logic compressor presets have been invaluable!

-Matt

[Lagerfeldt]

If you look in the top post there's actually a download for the preset. So you can see exactly what's going on for yourself, unless you don't have the Multipressor?

The crossover points in this case are simply the default ones which work fine as a starting point.

Using a fairly low ratio of 2:1 and a threshold of -48 dBFS or lower you will get constant gain reduction in all bands even with low level material. For this trick to work you do actually need a threshold this low, although I suppose -38 dBFS might work too in some cases - but don't count on it.

You want a rather squashed signal wth transients flattened and constant GR, but it won't really sound that squashed if you listen to it in solo - not using these settings in the Logic Multipressor.

Any other multiband device might sound different - I have no chance of knowing in advance.

If you look in the first post you will see that I mention that the parallel signal could be adding around 15-25% of the original signal in terms of dB.

[badhorsie777]

well look at that - I didn't think that the "preset multipressor" would allow me to import anyone's presets - just use the ones it came with.

Thanks again - and for humoring me

-matt

[Lagerfeldt]

Also see this thread about parallel multiband compression:

Multiband Parallel Compression

[badhorsie777]

Wow - that thread follows a familiar formula -

1. good question
2. a few responses
3. Bob Katz says something smart
4. bunch of ME's getting all bent out of shape
5. thread dies and is revived over time


...funny how often these things do that, isn't it?

Thanks, man - I've got a great new option with MBPC.

[PistolP]

tried it.
and yes, it´s working pretty effectively. however I replaced the Multiband with UAD Neve compressor and it was even fatter. the best option is hand the track over to a good ME - it will be even more better.

I really appreciate threads like this and I do like the SSL settings (done by Lagerfeldt) for the Logic compressor.

bstrgrds
P

[Dawkhouse]

Will this work when recording live instruments?

[malgfunk]

thanks. I used it on a mastering sesstion and it sounds great. thanks.

[DeBasement]

Nice post Lagerfeldt, and some useful tips - thanks!


Any tips on using parallel compression with outboard compressors? I've had trouble getting Logic's PDC to work correctly when the I/O plug is used on an AUX.

There was a thread about this here a while ago, and how inserting a dummy (bypassed) I/O plug on a channel strip fixes it a little... In my experience you still get phasing.

Do you ever use outboard parallel processing at mixdown with Logic?

[Lagerfeldt]

Because of the way parallel compression contributes to the overall signal I do not feel it matters a great deal that it's a digital compressor doing the work.

I have some nice compressors including a Crane Song STC-8/M but I use that mostly for "normal" compression during mastering. For that application I feel a digital compressor does not offer the same possibilities and quality as the analog counterpart though.

I'm thinking of getting a Danfield 726 with mix control, so that I may have analog parallel compression in an easy way but that's just a bonus feature for me.

[DeBasement]

Originally Posted by Lagerfeldt

Because of the way parallel compression contributes to the overall signal I do not feel it matters a great deal that it's a digital compressor doing the work.

I have some nice compressors including a Crane Song STC-8/M but I use that mostly for "normal" compression during mastering. For that application I feel a digital compressor does not offer the same possibilities and quality as the analog counterpart though.

I'm thinking of getting a Danfield 726 with mix control, so that I may have analog parallel compression in an easy way but that's just a bonus feature for me.

Fair enough, thanks. To my ears though, the compression on my Portico 5043 kicks the snot out of any digital comps I've got, even the UAD's, Waves, PSP and Logic contenders. It's just a shame that this bug in Logic's PDC implementation prevents me from using it effectively at mix time.

But for now I import the processed bus back into Logic and line it up manually -- Fun!

Different strokes for different folks -- I'm glad you've got something that works for you (obviously quite well, too), and I do appreciate the tips you've provided. Cheers.thumbsup

[Lagerfeldt]

Thanks mate.

However, I think you missed an important point in what I wrote.

The point being that in parallel compression there is a lot less to be gained from using outboard than during normal compression. I'm not talking digital vs. analog generally or normal compression at all.

In parallel compression the parallel signal is squashed completely, added at a very low level to the original signal and not very audible at all during loud passages.

In normal compression you'd hear the compressor on the whole signal working it's magic, or not so magic if it's a regular digital compressor.

So while my Crane Song STC-8/M certainly kicks the snot out of any digital compressor I've got, including the excellent Flux Solera II, it won't matter that much when we're talking parallel compression. Combined with the flexibility and easiness of working ITB for this trick, I think this is why digital parallel processing is popular among mastering engineers.

[DeBasement]

Originally Posted by Lagerfeldt

Thanks mate.

However, I think you missed an important point in what I wrote.

The point being that in parallel compression there is a lot less to be gained from using outboard than during normal compression. I'm not talking digital vs. analog generally or normal compression at all.

Yeah, I got your point loud and clear L. I just completely disagree with it.

I hear a huge difference between smashing the parallel drum bus with my Chandler TG1 and doing the same thing with the UAD, Logic or Waves equivalent. Huge. To my ears, of course, not somebody else's...

I find the sound of analog compression vastly preferable on parallel compression. That's why I use it. YMMV, as they so cryptically say...

[Lagerfeldt]

Ah, sorry :-) But I don't necessarily think we disagree actually, it just depends on what your objective is.

Your analog compressor colors the sound in a pleasant way, somewhat like adding an equalizer or some light distortion to the parallel bus ITB. Maybe you also get some added width too.

I think the question is why you're using parallel compression. If your objective is to get an invisible volume inflation during the mastering process then I would suggest using ITB parallel compression. If your goal is to enhance the perception of details or add coloration in a more subjective manner perhaps the outboard route is preferable.

[DeBasement]

Originally Posted by Lagerfeldt

If your goal is to enhance the perception of details or add coloration in a more subjective manner perhaps the outboard route is preferable.

Bingo.thumbsup

[Washington]

Lagerfeldt, I notice you mention inserting the I/O plugin on the track (not the aux) "in case you're using hardware". True, but if I'm not mistaken, this would induce the converter's latency - which is hopefully short but there nevertheless. In this case, the option of using a pre send wouldn't be available anymore. I could be wrong, haven't tested it yet. I don't want to sound like I know any better than you

For those interested, some guy has come with what seems to be a perfectly precise ping generator/measuring/delay reporting plug for Logic. It's a bit cumbersome but looks brillant. Here: Artificial Audio Main Page

[Lagerfeldt]

Originally Posted by Washington

Lagerfeldt, I notice you mention inserting the I/O plugin on the track (not the aux) "in case you're using hardware". True, but if I'm not mistaken, this would induce the converter's latency - which is hopefully short but there nevertheless. In this case, the option of using a pre send wouldn't be available anymore. I could be wrong, haven't tested it yet. I don't want to sound like I know any better than you

No, you are right, I deleted that sentence to avoid confusion.

Instead output the original and parallel signal to a new bus and insert the I/O plug-in there. That should fix the latency problem.

[Washington]

(splitting hair in length) then you would OTB comp both signals instead of only the original... oh, don't bother. Have a beer on me.

[Lagerfeldt]

While it could be considered a compromise it isn't necessarily so. The idea of the parallel signal is to add to the fullness of the track. Having this fullness added before OTB compression would be quite okay, in fact many would argue that's the way to do it.

[TC5]

Lagerfeldt, are you the one who posted a tip about multilayered reverb settings for Logic? I remember this very interesting thread but can't find it anymore. Thanks for the useful tips!

[Lagerfeldt]

You're welcome.

Hm, can't remember. Was it a whole thread devoted to the subject (not me) or an answer in an existing thread (could be me)?

Can you remember more about it?