problems with parallel compression

Whenever I use paralell compression I am very careful with the limiter. Make sure you have it in a soft setting since you might be just looking for some thikness in this Bus channel rather than volume.

P.S. I've learned that when this happens to me(loosing punch at the paralell compressor) 9 times out of 10 is the limiter.

Not suggested so much as the best possible solution, but just as an idea which you might like, have you tried compressing the bass & snare separately from the rest of the kit?

audio tracks also have a (post-fader) send going to a separate bus for parallel compression

My first thought: are these sends at unity gain? You'll get the effect you want only by how hard you hit the compressor input.

The level of the audio makes a big difference in how the compressor acts and it's 'character.' Each time you change the send level from one track, it affects the mix going in to the compressor and the way it's threshold works, and consequently changing one send level will affect how everything else on that send bus gets compressed.

I don't use sends at all with parallel compression. I do as you do, creating a drum mix first (say, bus 1). The I use bus 1 returning to an aux; that's the aux for P.C.
Often, I'll leave out the o/heads as usually I don't want to mess with their decay or spashiness, so I might treat them separately on their tracks. Again, I might also treat the room mic and Kick-Ext (if used) differently as well (with obscene amounts of compression!), as that's where the magic can happen (I'm working mostly with heavier rock) so YMMV.

On the P.C. aux, I use a compressor (not peak) and with a touch of EQ before, mainly HP and LP filters, maybe with a low-mid lift.

If I do this 'in the box' PSP Vintage Warmer works well for me. Also, Audio Damage's Rough Rider - there's a free version here. which can be effective, and is worth a try..

Now, if you've set up the compressor right, gradually increasing the P.C. fader should get you the effect.

The settings you quote don't help as they're going to change in every situation depending on the levels hitting the bus, although a very fast attack, and quite a fast release generally work best. I'm looking for anything between 15-25 dB of GR - crush those drums!

One more thing… using your limiter, do you have 'lookahead' on, and plug-in delay compensation off ? Set the latter to 'all' when mixing.

The answer is definitely the plugin delay compensation (PDC). If you set it to anything else then ALL, Logic does not compensate for the latency on your busses. So if you send the same source to two separate busses and one has a total latency of 20 ms and the other 40 then you will have a phase problem caused by the 20 ms time difference between the busses. Never use anything but ALL when you're mixing and are using busses (which for me is: All the time!).

The only problem with the setting ALL is that you can't use "software monitoring" without getting a huge latency when listening through Logic. That is if you have any plugins on your busses. Logic will delay your incoming audio with the amount of the latency of your busses. Not good.

Use a sound card with zero-latency monitoring to solve that.

Note that this still apply in Logic 8 as well as Logic 7.

Glad you sorted it out.

I could open up an Aux and select my drum fader bus as its input,

Yes, that's what I do. I'd forgotten the differences between bus and aux objects in 7 as I'm mostly in 8, where I only use aux objects, but it works fine. Typically my drum mix stays the same because of the player's natural dynamics, and if I change it ITB then I change the P.C. aux to follow, if necessary. Often, to add dynamics in a mic (verse .v. chorus) I'll push the P.C. aux and/or the drum submix.

Experiment and see how it works for you - I'd be interested in hearing how you get on. Also, remember to investigate how similar processing can be used for other applications, such as vocals, guitar busses, b. vox, etc (if appropriate for your material).

Hey John! On the limiter's lookahead, and delay compensation remark, can you explain better the effect this takes on the mix. If you have the time! Thanx!

Hi Apostol;

jdredge beat me to it, but I would describe it slightly differently - but the end effect is the same which he described.

Lookahead 'sees' into the future of the incoming audio stream from the HD before it's played back, so that a limiter, for example, can more accurately process incoming peaks exceeding the threshold by adjusting itself earlier. This all introduces latency.

So with plug-in delay compensation on, if a plug-in is on a bus or output, Logic delays other channels so that everything is in time. If a latency-inducing plug-in is on an audio/instrument track, it moves that track forward to compensate.

So without PDC on a mix which has tracks with plug-ins with latency, the tracks will play back slightly out of time, and depending on the lookahead specified, can cause weird phasing issues or (in extreme cases) sound out of time.

Apretiate the information! THANX!

I guess I'm just a little stuck on the usual parameters (ratio, threshold, attack/release, etc.), though I realize the Warmer doesn't operate in quite the same way.

Right. It is a bit confusing and there are only some controls which have usual plug-in equivalents. Look at VM as being a limiter, which in turn has an infinite ratio. The compression element of VM (as I understand it) affects the amount of compression underneath the ceiling. So the knee control affects that compression depth, rather than the compression curve, related to threshold, as seen in conventional compressors, like a sub threshold adjustment.

the knee sets the amount of compression applied to signals leading up to the ceiling, right?

Exactly. The ceiling, you would think, is the limiter ceiling for output a bit like Logic's adaptive limiter output. It is really a way of moving the output level to something other than 0 dbFS, and works with the saturation settings on the VM's back panel, and the way it handles the input side of VM. So I usually leave the ceiling at zero (as it's not being used for mastering) and change the drive, knee and saturation to taste. So the metering behavior you see, to me makes sense. Compare with pre and post, and adjust the drive, and it is more visually in step. I think it's more like a threshold than anything else. The knee is also affecting VM's make up gain, which you can balance with the drive knob to get the right amount of coloration.

Drive is, as you say, just an input level.

I always have FAT on. When used on drums, I change the rear saturation to less high and bass, more mid. I also change the freq. settings to be more active in the low mids, but this changes for each kit. I usually have brick wall and Auto (for release, not auto gain) on, with release set at X1.

The Mix control is mysterious to me. You would think that it works so that you can change the mix between an unprocessed input to the VM output and therefore use it on a drum submix without a separate bus for parallel compression, but it sounds different to me (and much better) when I use it on a bus set to 100%, so that's what I do, with some EQ before VM.