Who can offer tips on using a multi-channel compressor?

[dansouth]

Multichannel compressors are kind of a mystery to me (and perhaps some others). What's the point of having different ratios and thresholds for the different bands? What are good crossover frequencies for a mix, and how can the interaction of the bands be used to shape the overall EQ of the mix? I assume that the objective is to push highs and lows and limit mudrange, but I'm a bit confused as to the best way to approach this.

[big K]

I don't uderstand them the way some of the guys here do .. but the basic idea is that if you split it in to bands you can do more. for exaple you can compress just the low stuff, say below 300 hx... to give a punch to the low end, and you can compress the high stuff say over 2000hz, with a diferant ration attck and release, as to not add artifacts, and all while leave the vocal are in the middle untoched. this just on example... you can really do some neet stuff with this. hope that helped a bit... any one else care to expand(sorry bad pun I know....)?

[Hippie]

[quote]Originally posted by dansouth@yahoo.com: [b]Multichannel compressors are kind of a mystery to me (and perhaps some others). What's the point of having different ratios and thresholds for the different bands? What are good crossover frequencies for a mix, and how can the interaction of the bands be used to shape the overall EQ of the mix? I assume that the objective is to push highs and lows and limit mudrange, but I'm a bit confused as to the best way to approach this.[/b][/quote] Hi Dan, I have a few plugin versions of multiband compressors and (by default) the cross-over points are, low: 25hz - 200hz, mid: 200k - 2.5khz, high: 2.5khz - 20khz. I would assume this is a good place to start (for a hardware version) as a lot of 3-way speakers are split like this, too. I'd have to agree that the main objective of multiband compressors is NOT to have to compress the range of freqs. that don't need it. As for practical uses of using comps., I wish I could help, I'm still trying to get the hang of them after 15 years of tracking. I really think the compressor is the most difficult piece of audio equipment to fully understand, and comps. on an final mix, forget it, that is truly an art. I just 'noodle' around until I hit on a setting(s) that enhances the sound. (or, I just bypass it if no improvement comes from it.) I am still unable to listen to a track and say, "oh, why that needs some 2.5:1 at a -10 threshold, with a 25ms attack and a 500ms release, with a make-up gain of 2db", for instance. I hope some real experts pipe in on this subject; comps. are not one of my stronger areas. peace, Matt

[Anderton]

I just wrote an article on the subject for Keyboard...synchronicity, anyone? Frankly, multiband compressors are a bitch and a half to set up because there are so many parameters. I would suggest practicing with ONE band that you set to a particular frequency range, and leave the others bypassed, until you get a feel for how compression works in different bands. THE FOLLOWING IS NOT A RULE, but I often find myself using multiband compression as follows: Bass range: Either fairly heavy compression to even out dynamic problems, or expansion if I'm remastering something that's muddy or muffled. The expansion can help eaggerate peaks more. Lower mids: Leave 'em alone. Upper mids: compress a bit to bring out vocals and other solo instruments. Highs: Leave uncompressed, but raise overall level somewhat. Check it out...

[Groovepusher Sly]

One good explanation I heard was; With multiband compression, you can control the bass without your mids, and highs pumping. If you had a high compression ratio on a full range compressor trying to control a poping bass, the compressor would bring the whole track down by that ratio and, at whatever speed you had set. Is that close Craig? Sly :cool:

[Anderton]

Yes. Multiband compression is far more transparent than the single channel kind for that reason.

[Empty Planet]

Just FYI for the curious, there's a none-too-shabby DirectX multi-band comp plug available at http://www.db-audioware.com/dbm.htm which has a rather elegantly designed interface. It kinda makes all this rather weird theory pretty straightforward as you diddle around with it. Their demo policy (I'm not connected with it, honest, but this guy's a good coder) allows you to use it without limit for three weeks, so go play, go play....

[BP3]

Well, I'm tryin' out multichannel / multiband compression. I'm using a TC System 6000 for premastering some DVD mixes I've done. The beauty of a multiband compressor is the ability to tame out-of-control low end problems without changing the rest of the frequency spectrum. For instance, let's say you have a live recording with a drummer who has an inconsistent kick technique. By setting the crossover between lows and mids to a frequency just above the fundemental frequency of the kick, you can isolate the kick in a mixed product fairly well. The 6000 behaves as a high end Finalizer in that respect. I do find the TC method of multiband compression easier to use than the graphic multiband compressor available as plugins from Steinberg and others. The Nuendo compressor, for instance, can provide many compressions "knees" for each band. Where this can be useful in some cases, it generally cause more problems than a single ratio / threshold per band system.

[Alndln]

Sometimes I like screwing around and using it as an effect,like putting too much upper mid in the EQ and compressing it back down with the multiband which gives you a sound color without being overbearing.