These days if you're cutting a record on digital equipment, it's almost imperative to have some sort of audio compression acting on the signal. Audio compression helps all the dynamic subtleties to be properly boosted as well as maintaining control over fast or sporadic transient spikes. Audio compression can take place at the tracking stage , the mixing stage and then the mastering stage. If valves were used at the tracking stage then indirectly that's even more compression and if analog tape or tape emulation was used then again that's more compression. If the sounds were recorded through a speaker , like a guitar amp , then that's more compression. If it has distortion , then it has a type of compression. If you heard it on radio or television then it has more compression on it . If you heard it online , you most likely heard something compressed...and in different ways.
The Human Ear also acts like a compressor , although this behaviour is predominantly psycho-acoustic in nature it still colours an otherwise perceived dynamically linear sonic field .So in other words , in the real world as opposed to the 'recorded' world , the sensory information from our ears is automatically processed to accomodate what our mental auditory scope can handle.If the sound is at the extreme end of perception (too loud or soft) then our minds automatically adjust gain levels to either attenuate or enhance percieved sounds. Think about the difference in 'listening to something ' as opposed to 'hearing something '. Think about how loud that snare sounds when someone else plays the drum kit yet somehow doesn't seem as loud when you play it.
But this is besides the point? ..... actually it's not.
Audio compression, if used correctly , leaves the brain with less dynamic auditory information to process and therefore makes the listening experience far more pleasurable. Great record producers and engineers know this , sometimes without completely understanding why. And it doesn't really matter because sometimes the more you know the less you'll travel.Signals can be compressed many times in different ways either directly or indirectly to smooth out their dynamic ranges to the point that they barely make a VU needle rock.The brain hangs back so far that often it makes the recorded world sound so much more attractive and pleasurable to listen to than the real world. Some of the greatest vocalists owe their sounds to carefully crafted compression curves to make their otherwise unremarkable voice sit well in the mix.
Another aspect of the matter is that current audio digital recording systems now have a dynamic range of zero (no meter reading) to the SPL of a jet taking off (full scale meter reading). A dynamic range that clearly exceeds a hundred db. So naturally no-one would align full digit reading on a program meter to the SPL of a jet taking off on their sound system... it would just blow you away... This top point almost always has to be turned down to a more comfortable listening volume and by doing so moves the very bottom point of the scale closer to the threshold of human hearing.It is here that the sounds would drop out if compression is not used.
The onset of digital recording has also cultivated the type of mastering that has acted as the catalyst for the so-called 'loudness wars' , where for a while there final masters were pushed right up to the full scale reading to create the loudest recordings.If digital peak limiting is used , the result can sometimes sound too 'squared' and un-natural ... although it could be argued that the brick wall feels as though your ears are being protected..certainly it would appear that the brick wall may have saved a few systems but actually ruined lots of ears.
Some engineers claim they use they use very little or no compression during tracking or mixing , sometimes oblivious to the fact that the mastering engineer if employed may squash the signal during the mastering process so that the program is more comfortable to listen to.Other engineers or record producers are self confessed 'compression junkies' , applying massive amounts of compression during tracking mixing and naturally mastering. Compression is a BIG part of their sound and some are even secretive of their techniques...lol...Of course as with all the arts music has no rules , thankfully ,and these different techniques act as further colours to the pallett of music/audio production. These guys know that the sounds behind some of the greatest rock bands were no more than average sounding natrual signals that were carefully processed through layers of varying compression. Remove all that carefully layed compression and 'Nirvana' could well sound like 'The Kingston Trio'.
When it comes to types of compressors , there are countless options on the market. Hundreds , if not thousands of manufacturers are eager to offer something categorically 'new' to the unsuspecting public.Some new bell or whistle that may hold the secret to somehow getting ' that magic sound '....and to tell you the truth , as any great engineer or producer knows , the right sort of compression acting on the right sort of signal can actually make ' that magic sound '.
SMAC is the result of countless hours of designing , research , talking to engineers and producers and proto-testing different configurations of compression circuits with different techniques.As with all the Sebatron products , the unit was concieved as a whole practical recording tool that was drawn from the ground up. Each section was then refined and prototyped as seperate circuit blocks . After each aspect of the whole circuit was developed , all the sections were brought together and optimized for total operation..
Several prototypes featuring a range of core circuits were then built and the unit with the widest specification was used as the basis of SMAC.This ended up being a configuration known as 'Dual-Servo Optical' which has numerous advantages over single-servo optical configurations.For example , all LED ballistics in the opto-coupler are linearized by introducing the inverted cell. Due to the increased linearity and depth of the 'Dual-Servo' circuit , SMAC has a sound that puts it in between Optical and VCA type compression making its application wide and inherently flexible.
With SMAC you can expect a precious and invaluable tool that , with proper use , can make your mixes and productions stand out with from the rest , make your brain relax and make your music a lot more pleasurable to listen to.