Average and ultimate number of compression stages-What are your thoughts?

Discussion in 'Tracking / Mixing / Editing' started by jmm22, Jan 3, 2011.

  1. jmm22

    jmm22 Guest

    From first mix through to final master, there are several places where compression might appear. Looking at the T -Racks S3 panel view, I was startled to see 12 plug in slots, with 2 X4 in parallel, followed by 4 more, which is a heck of lot of potential places to stick a plug- in, in a compressor/limiter laden program like T- Racks S3.

    This has me wondering what the average number of compression stages there might be in the recordings of fellow recording.org members (mix and master included) and what you might think is the ultimate limit on the number of compression stages.
  2. JohnTodd

    JohnTodd Well-Known Member

    Answers will vary as much as estimates of stars in the sky. I, too, have wondered about how many compressors to use. I also wonder if my use of compressors is compensating for bad technique somewhere else.

    I record my lead Vox on two channels - one DI and one through a tube preamp. The DI is compressed heavily with boosted treble. The Tube is treated with a general compression.

    The compressor on the group sum of those two channels is another compressor that I use to "finalize" things. The other two compressors were tailored to those track's needs. This third one is the "real" compressor that makes the necessary changes so the vox will sit in the mix.

    My acoustics have a compressor on each one of them.

    My electrics have compression, either because of the distortion or I add one on clean tracks.

    My bass is compressed.

    My drums are NOT, but I use Addictive Drums, and those guys know better than me.

    I use NO compression on the bus for the studio master.

    In Wavelab, for mastering, I use the API-2500 Waves VST for a 1.5 ratio just to catch the peaks. The needles barely twiddle on that.

    So, I use a lot of compressors. Hey pros, am I using too much?
  3. jmm22

    jmm22 Guest

    Sorry, one clarification on the intent of the question, as I see that I did not phrase it precisely enough. I meant per track, regardless of what that track may be, because as you observe, compression will indeed show up everywhere over and over again on a complete mix.
  4. JohnTodd

    JohnTodd Well-Known Member

    I've used two on a track: first one catches peaks and second one for a more general compression effect.

    Also I've used a send to send the signal to another compressor to put a heavy squeeze on it while keeping the original uncompressed. It's called parallel compression, also "New York Compression":


    And the exciting compressor, which is similar but squeezes the treble a lot:

  5. jmm22

    jmm22 Guest

    I have noticed that staging the compression does something entirely different than just more heavily compressing the track in one go. This may be old hat to the pros, but it is a fascinating discovery to me. Naively, one would think the maximum number of stages for a single track (including compression at the mastering stage) is two, but if each stage is subtle, perhaps the number could be three, or four. One of the curious things that got me thinking about this was my Cubase default mastering setup. Once I imported the mix into the mastering window, Cubase automatically puts a dynamics plug-in (compressor/limiter) on the two bus in the track and on the stereo out bus. Now surely Cubase programmers expected any imported mixes to have some compression already applied, which means they anticipated three compression stages in total.

    I don't think the question is trivial. I would like to better understand the phenomenon of subtle but multiple compression stages compared to just one or two heavier compression stages.
  6. BobRogers

    BobRogers Well-Known Member

    I've been using a lot of vintage-style compressor plugins, so the eq curve of the plug is as important as the amount of compression given at each stage (which is almost never more than a couple of dB for me). In the CD I'm working on now I have the UAD Studer tape emulator followed by an additional compressor plugin on every track. Different compressors or each track - LA2A or the Fairchild on things that need fairly gentle compression, 1176 or LA3A if I want something more aggressive. Still only a few dB of gain reduction at any stage.

    I don't compress my drum or vocal buses - at least I have not done so on the recent CD. I'll limit the master bus if I'm going to listen to it compared to reference material before being sent out to be mastered.
  7. jmm22

    jmm22 Guest

    Thanks for the interesting reply. Is it possible to articulate what makes a given compressor more aggressive than another, if they have been set as near identically as possible? Is it just the intrinsic eq curve of the plug, as you indicate?

    My intuition is that if one is going to stack compression in any sense, the compressors should be disimilar. Is this a fair generalization?
  8. BobRogers

    BobRogers Well-Known Member

    With vintage compressors there wasn't much choice of ratio or attack and release times. So you can't really set them close. To me aggressive means higher ratios, harder knee, and (relatively) faster attack and release.
  9. AToE

    AToE Active Member

    I'm about to buy one of their UAD2Laptop pieces, was looking at that Studer emulator as well yesterday, looks like a lot of fun. How're you liking it so far?

    Jmm22 - I was about to say what BobRogers said, but then he said it first! A lot of those vintage comps (and plugins based on them) have almost no controls at all beyond more or less compression and some really basic level controls.

    EDIT: Also, I routinely use multiple comps per channel on vox, drums and bass. I don't often use more than 2 or 3, and when I do I attribute it to my own inexperience and lack of skill, as I should be able to get better results with less layers of comp I believe.
  10. AToE

    AToE Active Member

    Sorry for the double post, but I wanted to address this - the answer is NO. If you have vintage emulating plugins, then maybe yes, because one comp might be faster for knocking off those crazy peaks, and then one might be slower and can even out the rest of the track's volume, so in that case 2 different comps is a good idea, and often necessary. BUT - if you only have one type of compressor plugin you can still mimick this effect, you stack 2 of them and set the first one to faster attack/release, higher threshold (and maybe higher ratio, depends) to handle severe peaks, and then a second one with slower attack/release, probably lower threshold, and possibly lower ratio (huge generalizations there... take with salt).

    So you don't necessarily need different plugins, just different settings if your plugin gives you enough control.
  11. Davedog

    Davedog Distinguished Member

    I find that compressing compression invites a whole 'nother set of problems to a single track.
  12. TheJackAttack

    TheJackAttack Distinguished Member

  13. AToE

    AToE Active Member

    I thought it was fairly standard practice (not all the time, but often anyways) to use a fast comp in concert with a slower one, especially on percussion tracks?
  14. TheJackAttack

    TheJackAttack Distinguished Member

    Only if one of those is serving as a limiter.
  15. AToE

    AToE Active Member

    Ok, so basically what I'd outlined earlier, fast attack and release for the first comp, higher threshold and (possibly) higher ratio? Just so I'm understanding right, you're saying that it only works well if that ratio is set to infinity (or we'll say whatever the max is for that comp), or you're saying that whole technique works regardless of ratio because one is just targeting the high peaks with the first comp?

    Not trying to be obtuse, just trying to make sure I understand!
  16. BobRogers

    BobRogers Well-Known Member

    I like it quite a lot. It's really making this folk/country project I've been working on come together. By choosing tape type, speed, and bias you choose a mild eq curve that gives a cohesive feel to the songs. Controlling the input to each track adds a bit of tape compression to those tracks that need it. I certainly don't slam it, so a "real" compressor in the signal chain helps.

    The UAD2 Laptop solo comes with the LA2A and the 1176. (The vintage style compressors are what attracted me to the UAD-2 in the first place.) I use those a lot and you can get a lot of instances of them - even with the solo. The Studer is just out, so it is at its maximum price right now. Also, it eats a fair amount of DSP, so it may not be the most practical plugin for a solo. (Though you could put it on a track and bounce down and then turn the plug off.) You will get 14 day demos on each plug which you can activate at any time. Pay attention to how much DSP each plug uses and develop a strategy for using the solo.
  17. BobRogers

    BobRogers Well-Known Member

    These are not contradictory statements.
  18. jmm22

    jmm22 Guest

    Do you find these potential problems are noise related, or related to the track's dynamic structure?
  19. BobRogers

    BobRogers Well-Known Member

    The problems are dynamic. You can get some crazy nonconvex gain curves with two compressors. The practice of using a compressor with a slow attack and a low ratio at one threshold and one with a fast attack and a high ratio (e.g. a limiter) at a higher threshold is one that works to give a nice double knee gain curve that permits a controlled attack but a lot of punch. It's definitely possible to add a lot of problems, but if you keep it simple its not so bad.
  20. jmm22

    jmm22 Guest

    But would it be fair to say that if the compound compression is not audibly objectionable, or perhaps even pleasing to that ultimate aribiter (the ears, or more properly, the brain) then the gain curve geometry is moot? Although perhaps the case is that compound compression that is not objectionable simply does not exhibit a nonconvex gain curve. Also, can you elaborate in any way as to what these gain curves are, or some way I can imagine this? Or, are you aware of any online or text source where I can learn more about gain curve geometry? It would be beneficial to be able to visualize this concept to some degree. In my early imagination of this non-convex gain curve, it seems to be dependent on order, i.e., a "crazy non-convex gain curve" might be rendered convex merely by switching the order of compressors (with their respective settings.)

    And if it is possible to create a nice double knee curve, why not a nice triple knee?

    Also, what typifies the crazy non-convex gain curve sound? How will I know it when I hear it?

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