Compression new guidelines (Important)

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djsynchro
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Compression new guidelines (Important)

Post by djsynchro » Fri Dec 24, 2010 10:00 am

Punch, apparent l :x udness, presence... just three :x f the many terms used t :x describe the effects :x f c :x mpressing and limiting :x n an audi :x signal.

The terms c :x mpressi :x n and limiting have been in the audi :x v :x cabulary f :x r years, yet there is s :x me c :x nfusi :x n :x ver their definiti :x ns. The c :x nfusi :x n arises fr :x m the fact that b :x th the c :x mpress :x r and the limiter are devices that restrict the dynamic range :x f a signal, and the difference between them is :x ne :x f degree, with the limiter having the m :x st effect. T :x simply define each:

C :x mpress :x r: An amplifier, wh :x se gain decreases as its input level is increased.

Limiter: A c :x mpress :x r, wh :x se :x utput level remains c :x nstant, regardless :x f its input level.

B :x th definiti :x ns are valid :x nly after the signal being pr :x cessed reaches a certain level. Theref :x re, :x ne m :x re definiti :x n needs t :x be thr :x wn :x ut f :x r c :x nsiderati :x n:

Thresh :x ld: The level at :x r ab :x ve which the c :x mpress :x r :x r limiter begins functi :x ning.

In a situati :x n where input and :x utput are idealized f :x r a c :x mbinati :x n c :x mpress :x r/limiter, as the input level increases fr :x m -10dB t :x 0dB, the :x utput level, likewise, increases fr :x m -10dB t :x 0dB. Here the device is functi :x ning as a simple unity gain amplifier, with n :x effect :x n the signal level.

C :x mpressi :x n

:x nce the signal level exceeds the c :x mpressi :x n thresh :x ld :x f 0dB, the :x utput level will f :x ll :x w the c :x mpressi :x n curve, assuming a c :x mpressi :x n rati :x :x f 2:1, as the input increases 10dB; the :x utput will yield :x nly 5db m :x re gain. 

Limiting

In a limiting situati :x n, with a limiting thresh :x ld :x f +20dB, :x nce the input level reaches +20dB, there is n :x further increase in :x utput level. Hence, the device is :x perating as a limiter,. In actual practice, c :x mpressi :x n rati :x s :x f greater than 10:1 are c :x nsidered as limiting. :x nce the limiting thresh :x ld :x f +20dB has been reached, the :x utput level remains at +10dB, despite further increases in input level. Theref :x re, it sh :x uld be underst :x :x d that the limiter thresh :x ld d :x es n :x t necessarily indicate the maximum all :x wable :x utput level :x f the device. Rather, it indicates the input level at which the limiter begins w :x rking. 

Variable Thresh :x lds 

It sh :x uld be n :x ted that the same c :x mpressi :x n rati :x :x f 2:1 menti :x ned earlier will have different effects :x n the :x verall dynamic range depending :x n the p :x int at which c :x mpressi :x n begins (thresh :x ld). Als :x , the p :x siti :x ning :x f the c :x mpressi :x n thresh :x ld will influence the p :x int at which limiting must begin, if a certain maximum :x utput level is n :x t t :x be exceeded. 

Variable C :x mpressi :x n Rati :x s

M :x st state- :x f-the-art c :x mpress :x rs :x ffer audi :x engineers a variety :x f c :x mpressi :x n rati :x s fr :x m which t :x ch :x :x se. Assuming that an audi :x signal must be kept bel :x w +10dB, using higher c :x mpressi :x n rati :x settings will all :x w f :x r a greater dynamics range :x f the signal being pr :x cessed. 

Pumping and Breathing

It is relatively easy t :x determine the c :x mpressi :x n thresh :x ld and rati :x needed t :x prevent a wide dynamic range signal fr :x m exceeding a specified :x utput level. H :x wever, it sh :x uld be realized that - especially at high rati :x s - the acti :x n :x f the c :x mpress :x r might bec :x me audibly :x btrusive. T :x understand why, remember that the c :x mpress :x r is a variable gain device. The higher the c :x mpressi :x n rati :x the greater the change in gain. A c :x nstant high level signal, say +10dB will cause m :x re gain reducti :x n. When the high level is rem :x ved, the am :x unt :x f gain reducti :x n decreases as the c :x mpress :x r returns t :x unity gain. If the gain reducti :x n fluctuates rapidly, it may be quite audible as the backgr :x und n :x ise g :x es up and d :x wn in time with the c :x mpress :x r acti :x n, i.e. attack /release times, causing a breathing like s :x und. This can be used s :x metimes as an effect pr :x ducing s :x me killer results.

Example: The use :x f extremely sh :x rt attack times and l :x nger release times may create a backward-like s :x und, especially :x n percussive instruments. The fast attack immediately dr :x ps the signal, and then as the signal naturally decays, the release time setting brings up the gain, w :x rking against the n :x rmal decay. This effect is particularly n :x ticeable :x n a drum set, and particularly :x n cymbals. 

Pr :x gram Limiting

:x ften c :x mpressi :x n may be applied t :x the :x verall pr :x gram rather than t :x an individual instrument. Kn :x wn as pr :x gram limiting, this practice will prevent cumulative levels :x f the vari :x us instruments fr :x m getting t :x :x high :x r falling t :x :x l :x w. This type :x f gain c :x ntr :x l must be appr :x ached with care, since the adverse effects :x f c :x mpressi :x n are heard :x n the entire pr :x gram.

Pr :x gram limiting is :x ften used t :x raise the apparent l :x udness :x f a rec :x rd. Since the ear averages the s :x und level :x ver a peri :x d :x f time, a l :x w level pr :x gram with :x ccasi :x nal high level peaks will n :x t seem as l :x ud as an average level pr :x gram with n :x high level peaks. (C :x nfused yet?). In the quest f :x r l :x uder s :x unding rec :x rdings and br :x adcasts this type :x f l :x udness b :x :x sting is :x ften :x verd :x ne, much t :x the detriment :x f the finished pr :x duct. Meaning, what y :x u hear c :x ming :x ver the radi :x :x r televisi :x n is :x ften much different than the :x riginal pr :x ducers, engineers and mastering pe :x ple had in mind. 

Stere :x Pr :x gram Limiting

When a stere :x br :x adcast pr :x gram is limited, the gain regulating secti :x ns :x f the left and right track c :x mpress :x rs must be electr :x nically interl :x cked, s :x that the c :x mpressi :x n in :x ne track causes an equal am :x unt :x f c :x mpressi :x n in the :x ther track. This keeps the :x verall left-t :x -right stere :x pr :x gram in balance.

C :x nsider a stere :x pr :x gram in which the right track :x ccasi :x nally needs s :x me c :x mpressi :x n. During c :x mpressi :x n, a center placed s :x l :x w :x uld apparently drift t :x the left whenever the gain :x f the right track is affected by the c :x mpress :x r. T :x prevent this center channel drift, the stere :x interl :x ck functi :x n reduces the gain in b :x th channels simultane :x usly whenever :x ne exceeds the thresh :x ld :x f c :x mpressi :x n. This keeps the center placed inf :x rmati :x n fr :x m m :x ving fr :x m side t :x side with each acti :x n :x f :x ne :x r the :x ther c :x mpress :x r channel.
Last edited by djsynchro on Sat Dec 25, 2010 12:02 pm, edited 1 time in total.

djsynchro
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Re: Compression explained (Christmas Special)

Post by djsynchro » Fri Dec 24, 2010 12:10 pm

Another excellent thread by yours truly :D

djsynchro
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Re: Compression explained (Christmas Special)

Post by djsynchro » Fri Dec 24, 2010 12:10 pm

+1

crumhorn
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Re: Compression explained (Christmas Special)

Post by crumhorn » Fri Dec 24, 2010 1:44 pm

djsynchro wrote:
Pumping and Breathing
snigger snigger.
"The banjo is the perfect instrument for the antisocial."

(Allow me to plug my guitar scale visualiser thingy - www.fretlearner.com)

djsynchro
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Re: Compression explained (Christmas Special)

Post by djsynchro » Fri Dec 24, 2010 2:18 pm

crumhorn wrote: snigger snigger.
Your words although not racist CONTAIN a racist word. Be very careful now!

nathannn
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Re: Compression explained (Christmas Special)

Post by nathannn » Fri Dec 24, 2010 2:45 pm

ha!

now this is comedy!

i really did lol this time!

hilarious djsynchro!
:lol: :lol: :lol:
The Push / Novation Launch Pad / Novation Launch Pad Pro / Novation Launch Key
/ Launch Control XL / Machine MkII / Machine Studio / BeatStep / Livid OhmRGB / Livid Code V2 / Apc 40 MKII

no computers or synths

20 Copies of Ableton Live Lite.

nathannn
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Re: Compression explained (Christmas Special)

Post by nathannn » Fri Dec 24, 2010 2:47 pm

i am so sick of the "how to" threads. they are always always always about compression or mastering!
this is really funny! :lol:
The Push / Novation Launch Pad / Novation Launch Pad Pro / Novation Launch Key
/ Launch Control XL / Machine MkII / Machine Studio / BeatStep / Livid OhmRGB / Livid Code V2 / Apc 40 MKII

no computers or synths

20 Copies of Ableton Live Lite.

djsynchro
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Re: Compression explained (Christmas Special)

Post by djsynchro » Sat Dec 25, 2010 1:07 am

L :x L

contakt321
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Re: Compression new guidelines (Important)

Post by contakt321 » Sat Dec 25, 2010 10:48 pm

it just w :x rks

regretfullySaid
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Re: Compression new guidelines (Important)

Post by regretfullySaid » Sun Dec 26, 2010 7:17 am

So like, how do I get an audio file to play?
ImageImage

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Re: Compression new guidelines (Important)

Post by djsynchro » Sun Dec 26, 2010 9:48 am

Pc or Mac?

regretfullySaid
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Re: Compression new guidelines (Important)

Post by regretfullySaid » Sun Dec 26, 2010 10:12 am

Sony?
ImageImage

djsynchro
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Re: Compression new guidelines (Important)

Post by djsynchro » Sun Dec 26, 2010 11:32 am

:x

regretfullySaid
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Re: Compression new guidelines (Important)

Post by regretfullySaid » Sun Dec 26, 2010 1:22 pm

I lurnt hawta throw cds like Dolph Lundgren from " Come In Peace"
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