What are Optical Compressors? | Too Afraid To Ask

welcome to cs guitars the science of loud here's a phrase for you electro optical attenuator that's some pretentious wanky word word for what you might recognize as one of these a compressor pedal but not all compressors work in the same fashion some are purely digital while analog compressors utilize valves fets voltage-controlled amplifiers or in the case of our friend the compressor light electro-optical attenuators or optical compressors utilize light to gain a consistent dynamic response for the signal passing through them and it's this truly analog interaction which introduces interesting imperfections that make optical compressors so musical they almost become an instrument in their own right what makes them so special well let's find out so that you can no longer be too afraid to ask before we get started allow me a moment to address the parents hello parents this is a preemptive strike to hopefully lessen the quantity of um well actually comments below this video going forward we're going to be talking about compressor pedals and their operation as an entire unit to an audience of guitarists if you come from an audio production background some of my explanations may sound lacking to your studio gremlin ears but this video isn't for you this is to help musicians understand their magic little boxes not a detailed discussion on studio compression and all of its technical glory we don't need to see your technically correct essays on ratios and makeup gain thanks for understanding a bunch of nerds anyway let's start with the basics what the hell is a compressor a compressor pedal will do two things for your guitar signal firstly it will attenuate or decrease the level of any loud parts of the signal particularly the sharp attack transients at the beginning of notes and secondly it will amplify or increase the level of everything else granting longer notes more sustained before they die off this effectively narrows the dynamic range of the signal making the quiet and loud parts closer to the same volume level just like you put the signal into a vice and compressed it this is very very useful for a great range of applications but particularly for single coils and cleanish sounds single coils tend to have very sharp load transients and not much sustain to the rest of the note so compressors help to even out those differences compression is a natural side effect of distortion increasing the gain of a signal beyond the point at which it begins to distort we've naturally brought the loudest and quietest parts of the signal closer to the same volume playing with a lot of distortion can often sound better because this compression is evening out the inconsistencies in our bad playing techniques those inconsistencies are laid bare on pure clean sounds however using a compressor we can gain back that smooth consistent sound but without the distortion for clean country finger pickers or funk enthusiasts compression is a must but here's a tip for you metal heads if you've ever wondered why switching from your crushing high gain to your clean sound is a jarring mess that sounds terrible it's because you lost all that compression in this switch get a compressor for your clean sounds to match the dynamic range of the distortion section and you'll be able to slide between them effortlessly as mentioned the kong presser is a fine example of an optical compressor which uses light to accomplish its compression effect here's how that works a signal comes into the pedal is duplicated and passes to an optocoupler this is a device that contains both a light source an led in the case of the particular unit used within this pedal and a photocell a component that alters its resistance based upon the intensity of light incident upon it the louder the signal the brighter the led glows shining more intense light on the photocell lowering its resistance the output of the optocoupler is then used to determine when the compression should be applied sort of like an automatic gain control which reacts to the loudness of your signal as the signal level changes the brightness of the led fluctuates influencing the resistance of the photocell and eventually manipulating the gain it bears repeating that gain in this context is a signal multiplication factor how much the signal has been amplified gain does not mean distortion and using those terms interchangeably is wrong so we have a situation where the signal's dynamic range can be adjusted instantaneously using itself as a reference or at least that would be the theoretical ideal case using an optocoupler throws a few unique spanners into the works which prevent perfect linear control over the compression light travels fast it's the fastest thing in the universe and traveling any faster would break the unbreakable laws of physics however getting a lighting element to full brightness is a slow process relatively speaking furthermore getting them to rapidly change their brightness is difficult due to the thermal inertia of the materials used particularly if you're utilizing old filament bulbs while modern leds can turn on quicker and change their brightness more rapidly than the bulbs and electroluminescent devices of the past they are still sluggish in comparison to fat and vca operated compressors optical compressors need more time to swell into their compression giving them a longer non-linear attack attack being how quickly the compressor kicks in after sensing a loud part of the signal similarly the photocell side of the optocoupler is fairly languid in its release time release being how quickly it eases out of the compression after the loud part of the signal has subsided and photocells are pretty slow by nature light intensity on the photocell can produce a temporary memory effect if the led is bright enough for long enough it can blind the photocell for a short time preventing it from releasing even after the light intensity has subsided and when it does release it does so in a very strange non-linear fashion the first half of the release will happen very rapidly while the second half of the release will take much longer adding a lingering bloom to the compression this gives optical compressors a very dynamic response depending on how hard you hit them they will react differently when you really start to dig in compared to less aggressive playing the harder you go the more smooth and even the sound becomes because they simply can't react fast enough to do anything else this would make optical compressors a terrible choice if you wanted theoretical perfect control over knocking down short sharp transients in a mix without affecting the signal as a whole however when using them with guitars bass and even vocals they respond in a very organic and natural fashion adding a musical smoothness to the entire sound the non-linearity of optical compressors presents you with an effect that you can play how strongly they react is directly linked to how hard you play them making them very much part of the instrument as opposed to a technical utility device for correcting a recorded signal [Music] the compressor especially is designed with the intent of being a player's compressor alongside the compression level and global volume control we have independent controls for the attack and release allowing fine-tuning of the response speed longer attack times allowing more of the transients to be heard before the compression kicks in and longer release times ensuring the compression has time to bloom slowly before letting go chime is an act of treble control allowing you to add in a little extra high end to compensate for any losses when removing the transient spikes this unit also upscales the voltage internally so you'll get twice the headroom for your standard 9-volt battery this simply means it will stay clean as you lift the signal level and the compressor won't add any unwanted distortion no matter how much compression you are using compression can be a very difficult effect to demonstrate because done correctly it shouldn't be apparent unless you're very familiar with compressors this shouldn't be an obvious effect and it shouldn't change the tone and it can be difficult to hear what it's doing if you don't know what you're listening for the compressor in these examples is leveling out the playing dynamics bringing loud parts under control while increasing the sustain of the rest of the nose it balances volumes between pect and fingered strings as well as for techniques like pull-offs or tapping where you might expect some volume differences due to less energetic string strikes we will also use the compressor as a boost for distorted leads giving more sustain and saturation without adding more distortion in general the compressor is a make it better pedal everything should sound more cohesive and correct when it's switched on keep your ear out for that dynamic squash on loud parts of the signal [Music] [Laughter] [Music] [Laughter] [Music] [Music] [Laughter] [Music] so [Music] [Applause] [Music] [Applause] [Music] oh [Music] uh [Music] uh [Music] if you are into funk country or blues you owe it to yourself to check out an optical compressor if you haven't already and for those of you who are just curious about compression optical makes a great introduction as it is the most musical compressor around so there you go that's a brief look at optical compressors what makes them unique and how you can use them to get a better tone while i've used a couple of other different compressors in the past this compressor unit has really impressed me it affects the signal in a beautifully robust way it's a very playable compressor while optical units aren't ideal for every scenario i found that this marries perfectly for cleanish sounds when running my strat into the ad30 it achieves that iconic squash from vintage guitar sounds and adds a certain character to the musicality of the instrument the kong presser comes very highly recommended and there are links in the description should you want to find out more or even purchase one for yourself don't forget to click all the buttons you're supposed to to make this video viable to the ever-changing whims of the youtube algorithm that's all for now keep it loud and stay safe ah

Channel: CSGuitars

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Rating: 4.9556713 out of 5

Keywords: CSGuitars, Colin, all the gain, guitcon, scotland, victory, pickups, science, will it shred, whats the difference, studio, recording, guitar, amplifier, pedal, scottish, metal, cs guitar, cs guitars, collin, orange, orange amps, kongpressor, compressor, optical, optical compressor

Id: CP8VeDiJD0E

Length: 12min 35sec (755 seconds)

Published: Tue Sep 29 2020