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Understanding Compression Dynamics Processors (HW)
Old 20th December 2010
  #31
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I'm pretty good with compression (or at least I think I am) and I usually work by ear but I do have a technical question that I've never properly gotten the answer to and I've never tested it myself. So yeah, here goes:

Lets say you've got your ratio set to 4:1 and let's simplify it by not caring about the attack and release and threshold. When the signal hits 4 db above the threshold, instead of getting 4 full db of output (above the threshold) you only get 1 db (above the threshold), correct? OK cool.

So what happens if you only have signal going 2 db above the threshold? Do you get 2 db of output (above the threshold) because you haven't fulfilled the 4 db (above the threshold) requirement for the 4:1 ratio? Or do you get 0.5 db output (above the threshold) because 2:0.5 = 4:1? Or does it depend on the device itself?
Old 20th December 2010
  #32
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Storyville's Avatar
Quote:
Originally Posted by youngrob View Post
Great post. Can you do one of eq.
I will write up a thorough article on eq in a week or so and link it from this thread.
Old 20th December 2010
  #33
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Storyville's Avatar
Quote:
Originally Posted by LeoLeoLeo View Post
To see what the compressor does to your sound tonaly run a 1k tone into it, compress it in various ways. Listen to what comes out.
Nice tip.

I would do this even for a plug-in just to see what happens.
Old 20th December 2010
  #34
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Storyville's Avatar
Quote:
Originally Posted by MannyTheAvatar View Post
I'm pretty good with compression (or at least I think I am) and I usually work by ear but I do have a technical question that I've never properly gotten the answer to and I've never tested it myself. So yeah, here goes:

Lets say you've got your ratio set to 4:1 and let's simplify it by not caring about the attack and release and threshold. When the signal hits 4 db above the threshold, instead of getting 4 full db of output (above the threshold) you only get 1 db (above the threshold), correct? OK cool.

So what happens if you only have signal going 2 db above the threshold? Do you get 2 db of output (above the threshold) because you haven't fulfilled the 4 db (above the threshold) requirement for the 4:1 ratio? Or do you get 0.5 db output (above the threshold) because 2:0.5 = 4:1? Or does it depend on the device itself?
You get 0.5db of output. If you go 1db above the threshold you get 0.25db of output. IN THEORY. In practice, you usually get whatever comes out.
Old 21st December 2010
  #35
Understanding Compression

Quote:
Originally Posted by Storyville

Nice tip.

I would do this even for a plug-in just to see what happens.
And if I was real curious I would do the same to alot of freqs.
Really dig in the gr to see the differences.
Old 21st December 2010
  #36
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I really appreciate the effort to bring back constructive, in-depth debate on this forum!! I wish I had the excess experience and energy to bring this much to the table inhere.
Old 21st December 2010
  #37
Gear Addict
 

Quote:
Originally Posted by Storyville View Post
You get 0.5db of output. If you go 1db above the threshold you get 0.25db of output. IN THEORY. In practice, you usually get whatever comes out.
Haha, that's what I've always said though I've had some folks try to tell me otherwise. Still, it's probably best to not worry about numbers and just focus on what you hear...
Old 21st December 2010
  #38
Quote:
Originally Posted by MannyTheAvatar View Post
Haha, that's what I've always said though I've had some folks try to tell me otherwise. Still, it's probably best to not worry about numbers and just focus on what you hear...
that would be they optimum, but unfortunately i am not quiete there ... i NEED to hear, look at waveforms and level meters to help me set compression right. but i begin to "hear" compression in "shapes" a bit now! it took a while, but i can hear eg a snare hit, if it's getting fatter, or punchier, or thinner, flatter or with more or less sustain and so on.
Old 21st December 2010
  #39
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Quote:
Originally Posted by zinzin View Post
that would be they optimum, but unfortunately i am not quiete there ... i NEED to hear, look at waveforms and level meters to help me set compression right. but i begin to "hear" compression in "shapes" a bit now! it took a while, but i can hear eg a snare hit, if it's getting fatter, or punchier, or thinner, flatter or with more or less sustain and so on.
Fantastic! Do yourself a favor. Minimize your DAW screen and put a piece of tape over the part of your compressor that shows the meters if your in the box. If you are using hardware, just put a piece of tape over the meter. It can be unnerving not looking at the screen at meters at all - but if you want to really get this under your belt you gotta rely 100% on your ears. The end listener won't get to see any meters, they only hear the final production.

Meters and waveforms are to compressors what training wheels are to bikes. You don't see any BMX Bikers doing backflips off ramps on bikes that have training wheels - because those same training wheels that help initially eventually get in the way and make things more difficult.
Old 22nd December 2010
  #40
Quote:
Originally Posted by Storyville View Post
You don't see any BMX Bikers doing backflips off ramps on bikes that have training wheels - because those same training wheels that help initially eventually get in the way and make things more difficult.
damn it! i don't want to be the only BMX biker doing backflips with me training wheels on! i will take 'em off immediately - very good example! heh
Old 22nd December 2010
  #41
Here for the gear
 

Wow.. .
Really awesome post. . .
Thanks for sharing with us.
I like it and hope It will be helpful for me. . .
Old 23rd December 2010
  #42
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Storyville's Avatar
Quote:
Originally Posted by Brentlin View Post
Wow.. .
Really awesome post. . .
Thanks for sharing with us.
I like it and hope It will be helpful for me. . .
I hope it will be helpful for you too!


So, for those who are interested, I'm writing up an eq article. It covers a fair range of stuff - but I'd like to know if there is anything people want me to specifically address and go into detail about?
Old 24th December 2010
  #43
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illacov's Avatar
 

Quote:
Originally Posted by Storyville View Post
I hope it will be helpful for you too!


So, for those who are interested, I'm writing up an eq article. It covers a fair range of stuff - but I'd like to know if there is anything people want me to specifically address and go into detail about?
What different types of EQ settings do would be a great place to start.

Band
Notch
Allpass
Lopass
Hipass
Bandpass
Shelf

How the Q is used.

EQing and its effects on the phase of the source.

Also how the frequencies in the bands correlate to musical notes (MUST COVER THIS ONE).

Sweeping frequencies to find problem spots.

I recommend using ReaEQ or one of the Digidesign standard EQs as a reference for pictures since you can obtain ReaEQ in the ReaPlugs pack for free from Cockos or if you own PT you will have it as part of the software code.

Peace
Illumination
Old 24th December 2010
  #44
Understanding Compression

Seems to me there's enough technical info and "how-to" stuff out there, so I tend to be more interested in philosophical chats.
Old 24th December 2010
  #45
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Marshall Oliver's Avatar
 

+1 for being a trooper helping push this forum in the "levelheadedness" realm.
Old 24th December 2010
  #46
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Marshall Oliver's Avatar
 

Quote:
Originally Posted by bgrotto View Post
Seems to me there's enough technical info and "how-to" stuff out there, so I tend to be more interested in philosophical chats.
because those "chats" turn into pissing matches and are far more interesting to read.
Old 24th December 2010
  #47
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Oh, why not a little talk about linear eq... poles... and all the relations with phase...

Makes me wanna go into my math and physics courses from years ago all over again.. lol.


Nah actually depends for who is it...

[edit] illacov seems to agree though...lol
Old 24th December 2010
  #48
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Storyville's Avatar
Quote:
Originally Posted by bgrotto View Post
Seems to me there's enough technical info and "how-to" stuff out there, so I tend to be more interested in philosophical chats.
I agree - there's great resources on GS already about a lot of the technical stuff - and I also find that the while the level of expertise varies widely around these parts - people are generally on here because they are seeking to further their own knowledge - myself included. There are people who outclass me times ten on these boards with technical knowledge.

It took a while for me to really get it - but mixing for me happens in my head before it happens on the board. I think if people get into that mentality, they'll realize that the mix is about personality and emotion...

UBK said it best

"The song is everything. The mix is just it's bitch." - Greg Scott.
Old 24th December 2010
  #49
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u b k's Avatar
 

My experience with getting generic plugin compressors to behave like outboard is that I have to slow down the attack, sometimes by a factor of 3 and sometimes as much as a factor of 10, to get things feeling the way I need. If you're not careful, plugins can obliterate your transients which leaves the larger envelope untamed in comparison, so you get a sound with no useful transient but which still sounds uncompressed. This might tempt someone to think the answer is faster attacks, higher ratios, and/or deeper thresholds when in fact the problem lays in that initial grab and how it relates to what comes after. You have to learn to balance out how much you level that leading edge with how much the knee and ratio are leveling out the rest.

On a different note brought up earlier in the thread: opto compression is such a huge topic; different opto units are as unalike as different vca units. Some are wicked fast, some are very slow. I don't think it's accurate to lump them all together and say what they can and can't be used for, because they really do run the gamut. I think when people think of them as slow it has more to do with the release characteristics than the attack, because they can be as aggressive on the uptake as anything else.

The thing about opto is that it ('opto') refers to the detector topology, the part of the comp that figures out what it's responding to; 'vca' and 'fet' refer to the gain reduction topology, the part of the comp that actually modulates the level of the signal itself. In my admittedly limited experience as a designer, how a compressor determines what it responds to, iow the detector, is as or more of a factor in how it grabs as the gain reduction circuit itself.

And my last and final random observation is that plugins often exacerbate the wiry or 'hard' aspects of a sound when they're working hard, whereas a lot of the classier hardware does the opposite, it mitigates or softens these problematic areas. I have yet to understand why that is, but I'm working hard on cracking the code because I think it's at the heart of a lot of people's discontent with dsp compression, and I reckon if I can solve it I might make everyone's life a little better and in the process get that house on the beach that currently exists only in the back of my head.


Gregory Scott - ubk
Old 24th December 2010
  #50
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chessparov's Avatar
 

Great thread.

For those of us in the cheap seats, GENERALLY speaking...

If you're using low doses of compression (say 3 decibels or less), is it pretty hard for the compression connoiseurheh to tell the difference between a low end decent compressor vs. a high end unit?

Chris

P.S. Merry X-Mas BTW!.
Old 24th December 2010
  #51
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u b k's Avatar
 

Quote:
Originally Posted by chessparov View Post
If you're using low doses of compression (say 3 decibels or less), is it pretty hard for the compression connoiseurheh to tell the difference between a low end decent compressor vs. a high end unit?

More often than not, it is quite easy to tell the difference simply by running a signal thru the unit, no compression required.

Whether that difference matters, and whether the high end compressor is actually a better tool for that particular job, are entirely different questions. thumbsup


Gregory Scott - ubk
Old 24th December 2010
  #52
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ryst's Avatar
 

Quote:
Originally Posted by Storyville View Post

Once you start hearing shape, you will understand compression.
Great post, my friend.


I have to admit, I am not as technically savvy as a lot of engineers. I don't know certain terms or what they mean or why things work the way they do. I just know what sounds good. So even for someone like me who takes the "whatever sounds good" approach and not really pays attention to the "why" or even "how", posts like this are refreshing to read.
Old 24th December 2010
  #53
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Storyville's Avatar
Quote:
Originally Posted by ryst View Post
Great post, my friend.


I have to admit, I am not as technically savvy as a lot of engineers. I don't know certain terms or what they mean or why things work the way they do. I just know what sounds good. So even for someone like me who takes the "whatever sounds good" approach and not really pays attention to the "why" or even "how", posts like this are refreshing to read.

Technical knowledge is extremely useful in making PREDICTIONS when experience doesn't cover the area. However, technical knowledge can be extremely misleading - and the second one relies on it rather than the actual results the process becomes very much compromised.

Which is really the heart of why I'm writing this. Because using a compressor without understanding the [deeper] why - even with understanding of what a compressor does - negates the artistic concepts behind mixing.

A compressor can thicken OR thin a sound - change it's rhythmic properties and tone. Compressors are tricky because the results can be hard to predict - but if you know what you are going for, then it's merely a manner of discovering the right tool or process.
Old 24th December 2010
  #54
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Storyville's Avatar
Quote:
Originally Posted by u b k View Post
My experience with getting generic plugin compressors to behave like outboard is that I have to slow down the attack, sometimes by a factor of 3 and sometimes as much as a factor of 10, to get things feeling the way I need. If you're not careful, plugins can obliterate your transients which leaves the larger envelope untamed in comparison, so you get a sound with no useful transient but which still sounds uncompressed. This might tempt someone to think the answer is faster attacks, higher ratios, and/or deeper thresholds when in fact the problem lays in that initial grab and how it relates to what comes after. You have to learn to balance out how much you level that leading edge with how much the knee and ratio are leveling out the rest.

On a different note brought up earlier in the thread: opto compression is such a huge topic; different opto units are as unalike as different vca units. Some are wicked fast, some are very slow. I don't think it's accurate to lump them all together and say what they can and can't be used for, because they really do run the gamut. I think when people think of them as slow it has more to do with the release characteristics than the attack, because they can be as aggressive on the uptake as anything else.

The thing about opto is that it ('opto') refers to the detector topology, the part of the comp that figures out what it's responding to; 'vca' and 'fet' refer to the gain reduction topology, the part of the comp that actually modulates the level of the signal itself. In my admittedly limited experience as a designer, how a compressor determines what it responds to, iow the detector, is as or more of a factor in how it grabs as the gain reduction circuit itself.

And my last and final random observation is that plugins often exacerbate the wiry or 'hard' aspects of a sound when they're working hard, whereas a lot of the classier hardware does the opposite, it mitigates or softens these problematic areas. I have yet to understand why that is, but I'm working hard on cracking the code because I think it's at the heart of a lot of people's discontent with dsp compression, and I reckon if I can solve it I might make everyone's life a little better and in the process get that house on the beach that currently exists only in the back of my head.


Gregory Scott - ubk
Great post!

RComp in particular seems to fall into this weird way of reacting hyper fast. A 5ms attack off an 1176 seems significantly slower than 5ms on the RComp. I think part of the reason people like the Softube CL1B is that it seems to have a more realistic way of reacting than many plugs. As with much of the UAD stuff.
Old 25th December 2010
  #55
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chessparov's Avatar
 

Thanks ubk (Gregory).

Chris
Old 3rd January 2011
  #56
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Storyville's Avatar
EQ article is here for those who didn't catch the post:

Equalization: Hear Me Out | theProAudioFiles.com
Old 5th January 2011
  #57
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Daniel Ayo's Avatar
 

Storyville, the help you provide this board will not be forgotten. thumbsup
Old 5th January 2011
  #58
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Awesome! I really liked the way you explained everything.
Old 5th January 2011
  #59
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Storyville's Avatar
Quote:
Originally Posted by Daniel Ayo View Post
Storyville, the help you provide this board will not be forgotten. thumbsup
Hey, I'm flattered! Flattery will definitely inspire me to write more stuff heh
Old 5th January 2011
  #60
Gear Head
 

If you ever want to visualize what compression looks like and how it affects a waveform, check out Fabfilters Pro-C compressor. The audition-able side-chain is also exceptionally handy for getting a grasp on side-chaining as a concept.
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