What release knob actually does? (compressor)

Discussion in 'Working with Sound' started by iamculture, Sep 13, 2014.

  1. iamculture

    iamculture Newbie

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    I just simply cannot understand function of this powerful knob..I read lots articles about compression. I only understand that release need to be finished before next transient hits.(that is for drums,right)
    What about sustained sounds, how release works on them.... :dunno: I´am so confused
    When I saw this picture I become even more confused! lol

    [​IMG]

    Please help me understand this guys :thumbsup:
     
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  3. lampwiikk

    lampwiikk Member

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    Ok, the threshold knob determines when the compressor starts working. So as soon as the audio signal coming into the compressor goes over a certain volume, the compressor starts compressing. How much it compresses, or turns down, the audio signal is determined with the ratio knob. The release knob determines how soon the compressor stops compressing after the incoming audio is no longer over the threshold. You basically use it to adjust how "natural" the compressor sounds. Obviously if you have a dynamic sound coming in, and the compressor is turning it down and back up instantly everytime, it would sound pretty weird and artificial, this is where you get the pumping or sucking sound, from the volume constantly going up and down noticeably. With a compressor it can be more helpful to think of the controls in turns of what they do practically for your music, instead of what they actually are doing to your signal. But basically the attack knob and the release knob are the opposite of each other, the attack knob determines how quickly the compressor "grabs" the sound and turns it down once it sees it going over a certain volume, and the release knob determines how quickly the compressor "lets go" of the sound and allows it to return to its natural volume dynamic.

    With drums, if you had a quick attack and quick release, you would hear less of the initial strike and more of the ringing and the room sound, and if you have a slower attack and a slower release, you would hear more of the initial strike, and then the compressor would cut more of the ringing and room sound. If you want to really get a feel for it, use it on a tom track, you can get a ton of different sounds using a compressor and messing with the controls.
     
  4. Resonance

    Resonance Newbie

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    A natural sounding release time is somewhere in the region of about 90ms, it may be usefull to know if you can't hear whats its doing too well, I'd use it as a starting point if thats the case
     
  5. eheavy

    eheavy Member

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    I agree with lampwiikk It's better to think of how it affects the sound musically. Think of it like threshold is how much compression effect you want. Attack is when you want the compression affect to start. Release is when you want the effect to stop. Now where things get messy is when you factor in the fact that where the attack starts and the release ends also depends on the threshold lol.

    I like to think compression has 3 musical uses one for treating short samples and two for treating longer musical phrases. With shorter samples you can use compression as a transient designer, with longer passages you can use it to redesign the groove or 2 to level the signal to even out the volume.

    Now back to the release knob. To use it effectively you need 1 to have speakers that let you hear the compression and 2 you need be clear about what you are trying to do before you start. This is because where the release starts and ends also depends on where the threshold is set to kick in, so if you have a goal in mind it's easier to identify the changes you make by ear.

    I hope this helps
     
  6. Baxter

    Baxter Audiosexual

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    Release is the envelope time the compressor has, after a sound has gone below the threshold (again). Basically the time it takes the compressor to go back to "normal"/no compression.
    It's quite simple once you wrap your head around it.
     
  7. iamculture

    iamculture Newbie

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    Thanks for the reply! but I dont understand why the release time goes down (and how much it goes down) and then up to the original signal. Is release time actually sustain?

    http://manual.audacityteam.org/m/images/e/ef/Compressor_post.png
     
  8. SineWave

    SineWave Audiosexual

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    Excellent explanation, Lampwiikk. I would just like to add that if you want to learn how to work with a compressor try using some *uncompressed* drum loop because they are *very dynamic* and set the threshold quite low, ratio between 4:1 - 7:1, set the attack rather short [3-10ms] so the compression kicks in sooner and then work the release knob and it should be pretty obvious what it does. Start with a really short release [10ms] and then make it longer *slowly*. The key is to put the threshold low enough [like -24dB or more] so you can easily hear what's going on. This is how you can also hear what the attack sounds like more easily. Then back off the threshold to taste. That's how I still adjust the compressor when I'm not really sure what I hear - tired ears. Graphs are nice but they can't replace your ears and practical knowledge. ;) That's how I learned to work with the compressor and I got this tip from a really good producer/mixer. :wink: Cheers!
     
  9. iamculture

    iamculture Newbie

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    Im confused because release creates that volume dip and if I understand your explanations. But what about compressing long sustained sounds like pad or bassline, then I dont want to have volume dips because of release.
    Is my thinking wrong? Confused as f*** right now.lol
     
  10. kunkan

    kunkan Newbie

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    I will quote from the internet, something written some years ago on a place like this:

    "The Release function is a special one. While the Attack function compresses only the audio above the Threshold, the Release function is a bit different, it actually compresses the audio that falls below the Threshold. During the Release stage, the compressor will automatically detect where the audio is when it falls below the Threshold and begin to compress a little bit of the audio there. The Release function that you adjust on a compressor is the amount of time you want the compressor to take, in milliseconds or seconds, to go from that little bit of compression back up to the original, uncompressed, audio level. If any peaks go over the Threshold while the Release time is still active, then those peaks will be compressed until the Release time is over.

    Sometimes a little bit of compression right when the audio drops below the Threshold can help the compression sound a bit smoother, some might say "natural" or "musical". Also this bit of compression can help mask any hiss or noise that appears when the signal suddenly drops below the Threshold."
     
  11. Gulliver

    Gulliver Member

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    This diagram is very confusing, and it's even incorrect.
    Where did you find it?

    It's not the release time which is causing the volume dip, that's the compression itself.
    The release time detemines how fast the compressor stops compressing (dipping the volume), once the signal has fallen below the threshold. So it determines how long it takes for the signal to get back to it's full level.

    As for a pad sound, you usually don't need need to compress a pad sound, unless you want to add some colouration by a certain compressor.
     
  12. iamculture

    iamculture Newbie

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    Hey man, check out this video. In this video i dont understand why compressor dip the volume like that in release phase. Thats confuses me
    [media]https://www.youtube.com/watch?v=Mrx2nxQYsnQ[/media]
     
  13. lampwiikk

    lampwiikk Member

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    Ok, now your diagram makes sense, it's based on the audio example in a particular video. You will never have that audio example in your music, and since you find the diagram confusing and it doesn't apply to any real world application, stop stressing on it. Especially with compressors, you have to just keep watching different tutorials until one really clicks with you and you go "ooohhhhhh, I get it!". And also, of course, keep playing around with your compressor. The problem with it, and why compressors in particular are really hard for people to wrap their head around (including me) is that most of the time, if it's working right, you actually can't hear it, unless you A/B it over and over on a certain looped audio phrase, vocals especially, and notice that maybe a certain word that was sticking out as much louder, now all of a sudden sounds much closer to the rest of the phrase. And you also have to try very hard to set your compressor output so that when you listen back the output volume with the compressor working is the same as it is with it bypassed. It is almost impossible to hear what a compressor is doing to the incoming audio, if it also making it louder too. So much of why people put compressors on EVERYTHING, even when it doesn't need it at all, is because most of them tend to make the source louder, sometimes in a very subtle way, and "louder" always equals "better" right? (the answer is no, of course)...


    Now after watching the video I see what you're asking. It's not that the release time is causing a "dip" in the audio, what you see as a "dip", is the quieter part of his audio example. At the start of the release time the compressor is still working, turning even the quiet part of the example down, then as it lets go the audio is rising back up to the original volume over the period of the release time. So the compressor releasing is not causing a dip, it is actually causing it to ramp up to the normal volume of the quieter part of the audio example as the compressor lets go.

    Great video by the way, I've actually never seen it explained like that, it really helped me to visualize what the hell the "knee" setting does, which has always been a little bit vague to me.
     
  14. Baxter

    Baxter Audiosexual

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    A compressor is suppressing the volume when input signal is above threshold. Then it stops suppressing when the volume is below the threshold.
    This is what is happening here in the video (the "ramp up" to default volume).

    Think about it for a while. Sleep on it until tomorrow. Maybe you will get it by then. Good luck. Good night.
     
  15. iamculture

    iamculture Newbie

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    Thanks you all for awesome responds..compression requires a lot of practice I get that
    Big ups!
     
  16. Catalyst

    Catalyst Audiosexual

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  17. swing

    swing Newbie

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    Just an exra add: remember that you are working -usually- with really minimum snippets of time here. The gap in the example looks 'scary' because of the source, but it´s strange to face so extreme waveforms with music, possible, but strange, and if you set the times right it´s really difficult to 'feel' the gap. Once I read that -if you´re starting with compressors- and you just want to control the dynamic range, a good starting point for the release is knowing the duration (ms) of the shortest note/figure (timings in the take) you want to compress. And from there you have to experiment. That´s a 'safe' starting point because the compressor is fully recovered when the next transient is over the treshold, so it´s 'properly working'. From there, usually you start shortening more the release, and listening how it affects the tail after the initial peak you wanted to control. If you loop a short take and start tweaking I´m sure you´re gonna find nice spots for the release, the more natural -no noticeable- sounding settings. Also, once somebody told me that you usually have to try to find the 'shortest natural sounding release', and this is because is not the 'gap' the concern here, is the ramp up what you´re gonna feel unnatural if it´s too agressive or too slow. Also, don´t forget that your reverb tails, effects, and other instruments involved in your mix are also 'covering' -in some way- your 'gaps' :rofl: so you´re not destroying the song with some snippets of dynamic control. *no*

    ...and for pads, as Gully said, it´s not common to use a compressor, BUT if you have a pad with an annoying peak, maybe it´s better to fix it with some editing or controlling it by drawing an automation curve of the level. :wink:

    Hope it helps.
     
  18. Cav Emp

    Cav Emp Audiosexual

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    Well, maybe apples and oranges, but I think sidechain compression can be handy for adding movement and/or rhythm to a pad. I find it more useful than an LFO since your modulation isn't limited to regular intervals or specific waveforms. I guess you could automate the rate and depth of the LFO, but I'd rather just draw in the pattern I want and set and/or automate the attack, release, ratio, etc.
     
  19. rhythmatist

    rhythmatist Audiosexual

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    Do not be afraid of any virtual gear. You can't really break it, and all these devices have presets you can run through and listen and watch what they do. You have to learn to train your ears to become a good listener at an experienced audio engineer's ability. Sort of like body parts when you were young. Just play with it. For simplicity, I suggest the PuigTech in the JJP suite in Waves. Works just like a Pultech. Sounds nice, and is the simplest of compressors to operate and understand.
     
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