text: Get That Pro Sound The Ultimate Guide to Compression First Edition
  Publication date: January Compression
  Contents 1.
  Introduction......................................................................................... 4 Why Do We Need A Guide To Compression? What Is Compression, & Why Is It Useful?...................................... 5 Dynamic Range The Essentials: Set Up A Compressor In 30 Seconds.................... 7 4 Steps Anatomy of a Compressor Plugin.................................................... 8 Key Reverb Parameters.................................................................... 8 Other Common Parameters............................................................. 9 Compression Terminology.............................................................. 10 Compression Strategies: Assigning Compression In A Mix........ 12 Stage 1: Mix Balancing.................................................................... 12 Stage 2: Character Compression / Submix Compression........... 18 Stage 3: Stereo / Mix Buss Compression...................................... 21 Advanced Compression Techniques.............................................. 23 Parallel Compression...................................................................... 23 Sidechain Compression.................................................................. 25 Bonus Compression Pro Tips......................................................... 27 Conclusion......................................................................................... 32
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  Get That Pro Sound . and it can be yours too! Understanding what compressor parameters do in the abstract is not actually too difficult. Some producers will tell you that the importance of compression is often overstated. this is tricky: we’re talking about the relationships between sounds. and those charcteristics help define the role of the instruments part in the context of a full mix. But no more: Now the compressor is my best friend. and the mix as a whole. Compressors are your main tool for manipulating the dynamics of both individual hits and sounds. and it’s a different story. understand and manipulate the internal dynamics of your tracks. how it was played. People do ask about compression more than anything. the skill and sensitivity of the person giving the performance. One of the reasons people have a hard time understanding compression at first is that the differences in dynamics they introduce can be extremely subtle Page | 4 . But the thing about mastering compression is that you’re not really just learning how to operate a piece of equipment: you’re learning to listen to. or that it’s not as important as EQ. “That sound is high frequency. but even then figuring out how best to deploy them in the context of a mix is tricky. or too much? What are the right attack and release times? 2 Key Things: The Importance Of Understanding Dynamics & Dynamic Range Getting the results you want from compressors can often be the key to a tight.” But ask most people to evaluate a guitar part in terms of it’s attack or sustain. I was quite intimidated by the whole concept of compression for a long time. Again. and between the components of individual sounds – the envelope characteristics .The Ultimate Guide to Compression Introduction Why Do We Need A Guide To Compression? Part of the problem with learning about compression and using compressors effectively is that it can be quite a challenge to even understand what compressors really do. that one is low. but compression is our tool used to tame or accentuate the existing dynamics. It’s easy for most people to say. given a proper explanation. or what it is we’re actually trying to achieve with them. and most importantly. modern-sounding mix. Of course there are many factors that contribute to the dynamics of a sound.as much as the discrete characteristics of those indidual sounds. because they find it the hardest concept to understand or hear. It also means learning to listen in a different way than we’re used to: we’re used to evaluating sounds in terms of their frequency content. mainly because I couldn’t really hear exactly what difference it was making. Compression has to be one of the most confusing and elusive effects out there. or a whole track: what sort of instrument created the sound. How do you know whether or when to compress? How much compression is enough. or in some cases to introduce additional dynamics.
  In a more technical explanation. Remember: experiment. & Why Is It Useful? Your Personal Level Riding Assistant At it’s most basic.Get That Pro Sound . and you’ll get it at some point. and the relationships between sounds with different dynamics. This allows you to keep the level down to one that is manageable and recordable. But once you get how the internal dynamics and dynamic range of individual sounds and complete mixes can be controlled and shaped. making Page | 5 . listen. you’ll be well on your way to becoming a Pro Sound master. it knocks the hot signal down by that ratio. and easier to balance with the other parts at the mix stage. We can all tell the difference a high frequency sound and a low one. and then according to the compression ratio that you set. without the wild peaks. and more pertinently what settings are going to sound the best in the context of a complete mix. Think of a very dynamic part. as it is an obvious process pasted over the whole track. It’s easy when you know what to listen for. What is Compression. Part of the reason it’s difficult at first is that you’re listening for changes in the transients/dynamics rather than the frequency content. but to the untrained ear it can be a bit more tricky figuring out what’s happening to the dynamics of sounds through a compressor. and when it comes to the mix. This is why it’s important. you would either have to turn the whole thing up loud enough to hear the quietest notes and breathes. [and vice versa: automatically bringing up very low level signals]. Imagine you’ve got your very own studio lackey whose job it is to ride the fader on each track. Why Is Compression Useful? Introducing Dynamic Range Compressors were originally invented (apparently for location recording for the first ‘talkies’ in Hollywood) to reduce the dynamic range (see the box on the left for an explanation of dynamic range) of a recording. There are going to be loud sections and relatively quite sections within the same performance. It will monitor all the incoming signals and then act like it is pulling down the fader the instant that high volume peak occurs. what the compressor is actually doing is reading the incoming signals. not only will you feel like a sonic wizard. once you grasp the basics. making it less likely to distort at the recording stage. incredibly quickly and accurately.The Ultimate Guide to Compression – compression is as much about the cumulative effect of many individually compressed sounds being brought together. to consider an overall strategy for how you’re going to implement compression in a mix (much more on this later). a compressor is basically an automated level fader – when the audio is loud it gets turned down and when it’s soft it gets turned up. such as a vocal line: throughout the track you might want to hear everything from intakes of breath before each line to the full-on chorus at the climax of the song.
  You’ll generally only find tape hiss and electrical hum here. so you can think of compression as both a way to make loud sounds quieter and to make quiet sounds louder. Finally there is the highest level in the total dynamic range. However. making it easier to find a static fader setting that works. the maximum level: any level beyond this will not be reproduced properly and will distort (0dB in your DAW). the quieter signals will be louder than before. It will reduce the level differences between the loudest and quietest parts. but compressors generally also have an output level control to compensate for the loss in gain and bring the overall level back up. and lose completely all the details and nuances of the performance. fatter notes and punchier drums – could actually be very pleasant.The Ultimate Guide to Compression the choruses ridiculously overbearing. The mechanism of compression means that loud sounds are reduced – ‘compressed’ – in level. are they making loud sounds quieter or quiet sounds louder? The answer is they can do either. Compressors could be used to manipulate the dynamics of sounds creatively: not just keeping levels within certain technical limits. which is the best level for recording your incoming signal in order to minimize distortion and overcome the noise floor. no static level gives a good balance because the difference between the highest and lowest signal levels – the dynamic range – is too large. more sustain. Next up is the nominal level. we’re talking about the difference between the noise floor and the maximum level. technical use of compression. because here’s a key aspect of compression: If you apply enough make-up gain to bring the peak levels back to where they were before compression. accentuating or diminishing certain aspects of a single part or instrument. So. Page | 6 . things got a lot more interesting when people realised that the ‘side-effects’ of heavier compression – smoother sounds. when we talk about total dynamic range. You’ll want to make sure that even stray loud peaks stay within your available headroom. or vice versa: turn everything down. Dynamic Range: One-Paragraph Primer The lowest level in the dynamic range is the noise floor. The difference between the noise floor and the nominal level is called the signal-to-noise ratio. Essentially. The compressor does this by turning down – ‘compressing’ – the louder parts so that they match the quieter parts more closely — and all it needs from you is an indication of which signals you think are too loud. The difference between the nominal level and the maximum level is referred to as the headroom.Get That Pro Sound . That’s the original. So if compressors reduce dynamic range. but changing the character of the sound. Stay with me. Compressors remedy this problem by reducing a sound’s dynamic range.
  and heavy compression can take the ‘life’ out of an instrument or performance. Play back your material on the track where your compressor is inserted. even though the peak level is unchanged. 1. in effect. Leave the Attack and Release at settings that feel appropriate to the material you’re playing back. insert a compressor plugin on an audio track. particularly drums: this is what’s known as tuning the compressor to the sound you want to achieve. You may want to have as much sustain to the notes as possible. The Essentials: Set Up A Compressor In 30 Seconds Start with a low threshold of around -20 or -25 dB – this will then enable you to clearly hear what all the other controls and adjustments are doing to your sound. Set the Ratio to a typical starting value of 2. you have eliminated your original playing dynamics. that wasn’t in the original recording. why not use loads of it. and immediately bring the Threshold down quite low to around -20dB to -24dB – this will then enable you to hear very clearly what all the other controls and adjustments you’re going to make are actually doing to your sound. (Remember to stop. But in the process. adjusting to taste. Try sweeping the Attack control from fastest to slowest. 3. Having said that. With this method. The Downside: The Compression Tradeoff You may be thinking. you’ve lost the nuances in your accented notes and phrases.The Ultimate Guide to Compression As quieter parts of sounds can. Then do the same with the Release control. and listen to the difference in sound. The attack of an instrument is a very important factor in the instrument’s sound. you can bring the threshold back up to a more useable level. Go back and tweak the Ratio a little bit to understand what it does. on everything? What happens when you over-use compression? Take a typical rhythm guitar part. means that the average energy level is higher: which generally results in a more powerful or punchy sound. the Ratio Page | 7 . and you’ll get better results making judgements by ear. compression ultimately has the effect of boosting the average signal level. you’ll often be able to find a combination of settings that just seems to work intuitively with your sounds. compresses peaks above the threshold more. you can bring the threshold back up to a more useable level. adjusting to taste. in turn. Essentially. use your ears and close your eyes at every step of the process. You can tweak the knob without looking at it. be increased in level relative to the loudest peaks. Once you have those optimally set. First. which we’ll discuss later when we look at Parallel Compression.Get That Pro Sound . there are ways around this limitation. Once you have those optimally set. and so you apply some really heavy compression to bring up the level of the quiet tails of each note and make them sustain for ages. if compression is so good. This. It’s quite a different experience. so while you have all the sustain you wanted.) 2:1 or 3:1.
  For example. for extra sustain. The level still goes over the threshold. The attack setting becomes critical when dealing with instruments that have a pronounced attack of their own. The release time is generally longer than the attack time. the compressor acts on the peaks once they pass the threshold. setting a slower attack time will be the way to go. where the signal doesn’t need to be compressed anymore. for example. ‘apply between 3dB and 5dB of gain reduction’ on the loudest peaks/notes. Ratio This refers to how much the signal above the threshold is reduced. The amount of compression or Gain Reduction is usually indicated on a meter. such as bass guitar or most drums. with a very fast attack setting. which would result in greater sustain on each note or hit. you want to make sure that the compressor is responding fast enough to the incoming signal. in milliseconds. the peak won’t have reached the maximum level and distort. the more the incoming signal will be compressed. This is because more of the noise peak is now above the threshold level.The Ultimate Guide to Compression 4. Attack This refers to how fast. so there is more to squash. Many guitar players use compression like this. or set it slower. and you can use this as a guide to. Release This refers to how fast the compressor ‘lets go’ of the incoming signal once it has gone back below the threshold level. (or the threshold is set too high).Get That Pro Sound . You can set up a fast/short release time and cut off the signal processing quickly. if you set the ratio to 3:1. relative to it’s original level. because if you’re trying to control the peak levels. Page | 8 . the compressor will allow only 1dB to pass. but assuming that you set the threshold low enough and used an appropriate ratio. for every 3dB your incoming signal goes above the threshold. At othe rtimes you may want to let the attack portion of a note through and only process the later body of the sound: in this instance. Also keep in mind that if your incoming signal never reaches the threshold level. none of the signal will actually be compressed. Anatomy Of A Compressor Plugin Key Compressor Parameters Threshold Every compressor will have these essential controls: This as the decibel level at which the compressor will start working. You can think of it as a line that is lowered onto your signal: the lower the threshold level.
  where you want to be sure that both channels are being compressed by exactly the same amount. Page | 9 . Sidechain compression as a specific technique is covered in a later chapter. If you find yourself using a very high Make-up Gain setting. controlling them as if they were a single source. which would not otherwise necessarily be the case if you have different sounds panned to different sides of the stereo field. There are subtle. Sidechain / Key Some compressors are able to ‘listen’ to another signal and apply compression. creating an extremely dynamic sucking or whooshing sound (see Breathing and Pumping below). Soft knee compression is typically suitable for vocals and whole mixes. synth and pad parts every time it hits. based on that ‘sidechained’ source signal. the signal is compressed the moment it goes above the threshold to the full extent of the ratio that is set. or simply Gain or Make-up). squashing a signals dynamic range will generally change its apparent overall level. nominal level in the mix. simply allows you to reinstate the compressed signal back to a useful. The extra signal is also sometimes referred to as the ‘Key’ or ‘Key Input’. if you have a loud sound panned hard to the left. to the process sound. With a soft knee setting. With a hard knee setting. Something to be aware of here is that by raising your signal back to the nominal level. This is useful when you’re compressing stereo signals. So the Output Gain (also called Make-up Gain. technical uses for sidechain compression. the left channel level will be pulled back by the compressor. hard knee compression is usually right for bass and drums. the compression is applied more gradually – literally more softly – making the effect of the compression less abrupt and audible. you are also bringing up the level of the noise floor by the same amount. Other Common Parameters Knee Not every compressor model has these options. the Stereo Link switch usually sums the two inputs together. For example. which also means more overall compression can be applied. but many do: A feature common to many compressors is the option to compress with ‘hard knee’ or ‘soft knee’.Get That Pro Sound . which in turn will make the mix appear to swing towards the unprocessed (because there’s no sound) right channel. You can think of choosing the knee setting of a compressor as similar to setting the attack knob – it adjusts how ‘tough’ the compressor appears to be on your signal. you might want to try increasing the level of the signal going into the compressor to begin with instead. Here it can usually be heard where the kick drum appears to punch holes in the bass. Stereo Link On dual-channel compressors.The Ultimate Guide to Compression Make-Up Gain / Output As we mentioned already. but it’s also very common as a creative effect in dance and electronic music.
  Because of the inner workings of valve-type technology. but short duration. a mathematical means of determining average signal levels. which means that short duration sounds aren’t perceived as being as loud as longer sounds of exactly the same level. This is called an RMS response (an abbreviation for ‘Root Mean Square’). that contributes to a specific. This isn’t generally regarded as a fault. Linear vs. these can require the compressor to make very fast changes in the gain. This results in natural-sounding compression. When the effect created by thiese sudden/extreme changes is audible. whether by accident or by design. the amount of gain reduction that a compressor applies as the input goes above the threshold should be reasonably linear: so no matter by how much the input exceeds the threshold. high amplitude sounds may pass through at a higher level than you expect. Here. Some compressors allow you to switch how they respond to incoming signals. The implications of using a compressor with an RMS control law are that the compression will sound natural. ‘musical’ character of their own. loud sounds may slip through without being processed the way you would expect. but a feature of many of the most celebrated compressors. it’s referred to as ‘breathing’ or ‘pumping’. most compressor models are not perfectly linear. the gain control responds more accurately to brief signal peaks than in the RMS ‘averaging’ mode. in the sense that short duration sounds aren’t perceived as being as loud as longer sounds of exactly the same level. This ensures peaks are more accurately controlled. Compression Terminology Breathing And Pumping When you set very short attack and/or release times. where the transient peaks are a larger part of the overall sound than with other instruments. One solution when feeding digital systems that can’t tolerate overload is to use a fast acting peak limiter after the compressor.The Ultimate Guide to Compression Switchable Peak/RMS modes Compressors are designed to respond pretty much like the human ear. the output level increase will always be the fraction of that amount determined by the ratio setting. Non-Linear In theory. short transient sound occurs. However. but the potential downside is that it can also squash everything more harshly whenever a loud. but short. Page | 10 . In RMS (which stands for ‘Root Mean Square’) mode. This is where Peak mode comes in. the compressor responds much like the human ear. Peak compression is generally reserved for tasks like treating individual drum and percussion sounds. it’s not uncommon for the amount of gain reduction to reduce at higher signal levels: effectively lowering the ratio of compression at those higher levels. Because of this.Get That Pro Sound .
  or otherwise. you may very well want to imbue your sounds with nice tube warmth (subtle distortion inherent in most analogue circuitry). Teletronix LA2A Turn up the peak-reduction knob to increase the amount of compression. SSL Buss Compressor UREI 1176 You get more compression as you bring the threshold down.Get That Pro Sound . Character Compression Linked to the differences between linear and non-linear compression. Clearly these compressors are fast and simple to control. The differences are essentially how you control the amount of compression that is applied. you want the compressor to work ‘transparently’. or introduce the audible dynamic effects of heavy compression. different compressors process material. these terms refer to how ‘invisibly’. These generally have some kind of automatic Make-up Gain function working behind the scenes. you’ll want to reach for a non-pristine. it can be useful to figure out which of the classic types they are most similar to – this will give you some good ideas for what type of material your plugins might be best suited to. The Waves Renaissance Compressor plugin uses this method. keeping the subjective level of the audio consistent no matter how much compression you’ve dialled in. Three Classic Compressors: Three Compression Control Paradigms There are three favourite hardware compressor models that between them illustrate the three most common control layouts found in any compressor. character effects. One-Knob Compressors There are also a few ‘one-knob’ compressor designs with only a single Compression control. The input gain control pushes the signal up against a fixed compression threshold to increase the amount of compression. Conversely. non-linear ‘character’ compressor that will favourably colour your material.The Ultimate Guide to Compression Transparent vs. in this case. If you want to really get under the skin of your favourite plugin compressors. whether hardware or plugin. making them useful for dramatic. Sometimes you’ll want to compress a part without the audible side affects that give away that it has indeed been processed. Just be aware that it’s especially easy to overdo the amount of compression applied with this type! Page | 11 .
  you won’t be able to change it later if you want to. Stage 1: Using Compression To Fix Mix Balance Issues Which Parts Do I Need To Compress. and how the different controls work together to enable us to achieve that. and as a creative tool? As we’ve already discussed. they’re the main carrier of the vital melody and lyrics in most songs. It’s time to formulate a strategy. for example. or any instrument with a high dynamic range. all in one go. effective compression is far more about creating a cumulative effect built up through a mix than it is pasting on heavy compression at the end. and so you actually want to maintain a relatively small dynamic range. Whilst it’s of limited use to offer totally prescriptive settings for these. A Note On Compression While Recording With recording it’s generally best to keep everything as ‘dry’ of effects and processing as possible. However. some instruments are typically more likely to need dynamic-range control than others – vocals. and at What Point in the Signal Chain? So.Get That Pro Sound . introducing unwanted distortion. some control of vocal levels will usually be required. here are some good jumping-off points for common instruments: Which Parts Do I Need To Compress? Vocals Vocals are the obvious place to start with applying compression. This Page | 12 . assuming you’ve got your arrangement of cleanly recorded tracks up in your DAW. but pretty much everything in a modern production will sound better with at least a little compression. transparent compression just to tame any wild peaks and make sure that you’re going to be working with a clean recording. bass and drums are the usual key places to start. If you’re recording a vocal. it’s time to start with our mix compression strategy. But how do we implement compression smartly in the real-world context of a mix. because if you track anything with additional processing included in the recording. However. Although they naturally have a very wide dynamic range. from kick drums to flutes. in some instances processing an incoming signal for recording is smart.The Ultimate Guide to Compression Compression Strategies So now we know what compressors are designed to do in principle. Every mix will be different. it will be quite easy to overload the recording device. This is a typical case where you’ll want to apply some light. Even in natural-sounding acoustic mixes. so that we can build the most effective and flexible overall effect.
  The ratio to start at will vary from singer to singer: some voices are very strong and loud. with a smaller dynamic range. use a soft-knee setting. but it’s typically much more effective to use compression. When compressing a live drum performance. Bring the Output or Make-up Gain control up to compensate for the level drop. at least compress the snare. With the vocal playing back. others will be quieter. and can handle. lower the threshold until the compressor is working on the signal peaks – you’ll know you’re in the right ballpark when the meter is displaying between 3dB and 8dB of gain reduction on the loudest notes only. We’ll start by catching and controlling the loudest peaks in the performance. Snare And Toms If nothing else. As such. Drums Drums are usually compressed due to their hard attack/transients. which will allow more of the initial transient through. and can be transformed by compression in a mix – one thing to remember is that pretty much anything you do will be an effect.g. 1. 2. Bass Compression is key for bass parts of all types – synth. You can also try aiming to set the release to a speed where it can return to zero between beats. 0. Kick.09ms) and medium to slow release (100ms). as having strong control of the attack of a bass sound is key to shaping it’s overall sound. but even where the dynamics are already quite restricted compression is advised because of the importance of controlling the levels of low mix frequencies. Try starting with a 2:1 ratio on sung material (but try as high as 6:1 for voiceovers or spoken word). Bass guitars in particular can have quite a wide natural dynamic range. the best threshold and ratio settings will depend on the consistency of the drummer: with a less consistent drum track. not against it. because this drum will have particularly loud Page | 13 . acoustic – as here it will help you get a really consistent. fast attack and fast-to-medium release. giving the hits more snap. so the compressor is working with the groove. Generally use a hard-knee compressor/setting if you have the choice. stick or beater so they retain teir ability to punch through a mix. try using a lower ratio to maintain as even a sound as possible. relatively strong initial compression. it’s even more tricky to advise starting settings! But here are some tips and things to consider: It can be a good idea to set any drum compressor to a medium-slow attack. It can work to bring the threshold down lower than you would simply to catch stray peaks: bass benefits from. electric bass guitar.Get That Pro Sound . Start with a 4:1 ratio. solid foundation on which to build the rest of your track.The Ultimate Guide to Compression could technically also be achieved though fader automation. a fast attack (e. 3.
  with fast time settings. 1. no matter where you position their fader level? When you can’t find a good static fader position for a part. Can you hear everything you need to? Are there any parts which aren’t coming through clearly or stick out of the mix too obtrusively. If you’re working with programmed or electronic drums rather than a live kit.The Ultimate Guide to Compression transient peaks on each hit. start with a 2:1 ratio. or bringing up the body or sustain of sounds: compression in it’s classic application. Overhead Mics For some life-giving sizzle. with a low threshold. Page | 14 . To adjust the snare sound to best fit your track. To get a good sustain. Guitars Distorted rock guitars often don’t need any compression at all. start with a 4:1 ratio. Then play the note you want to sustain. lower the threshold to grab just the loudest peaks. fast attack and a slightly slower release. a high ratio and low threshold. and raise the ratio until the sustain is as long as you want it. reducing the dynamic range of parts so that they each have a more consistent level. for 1-2dB of gain reduction. for example. fast attack and slow release. For cleaner or acoustic guitar. and bringing the threshold higher to taste e. playing back. fast attack – and a slow release to preserve the natural decay. Synths Synth parts can also often be left alone. Cymbals Start with a 2:1-3:1 ratio. and so are easier to balance against each other. as anything heavily distorted will already have been leveled out dynamically by nature of the distortion process. start with a 4:1 ratio. Then. programming a constant pattern of splashy cymbal hits and compressing with the settings above can work really well to loosen up and excite the groove. try sweeping the attack faster or slower to find a sweet spot. First. an R&B ‘snap’ or more of a pop ‘slap’.g. concentrate on the balance. With a soft knee setting.Get That Pro Sound . and perhaps 4:1 for non-overdriven electric guitar. usually because their dynamics are generally already shaped at the programming stage to fit the role of sharp lead or more static pad. Using A Compressor In The Mix: Fixing Balance Issues Basic Dynamic Range Adjustment Walk-Through At this stage we’re primarily concerned with controlling stray peaks on individual sounds. try limiting (compression with an infinite/highest possible ratio) the drum room/ambience/overhead mics fairly hard.
  try bringing the threshold down further. Play back your mix again and see if you can now balance the compressed track better.The Ultimate Guide to Compression it’s a sure sign that some compression (or multing. For example. Check New Level – Problem Solved? At this point. and whether the compression can deliver the static faderlevel you’re after. but quickly gets very fiddly if you try to use it to deal with lots of short-term balance problems (lots of single notes or words that are too loud or quiet). so that the 4. use a little compression at various stages. Insert Your Compressor and Select A Preset. but still compress that solo so that a few over-zealous notes don’t pop out too far. To start with. so it‘s a good idea to keep the touches of compression as light as possible at this stage. Remember. bring the threshold down low. Try multing to solve balance problems first. When To Mult Tracks Rather Than Compress Multing is a simple DAW technique of copying audio parts to an additional track (or just duplicating the whole track) and then adjusting the level of particular notes and phrases to make the overall level more even – thereby potentially avoiding the need to use compression or level automate level changes. see the box below) is in order. so that the effect is cumulative rather than shovelled on in one go. Pushing your channel compressors too hard is a common mistake that can slowly suck the life out of a mix if it’s duplicated across all your tracks. Then adjust the make-up gain (or equivalent output level control) to bring the overall level roughly back up to the pre-compression level. you could mult out a guitar solo from the main guitar track to give it a higher fader level.Get That Pro Sound . but don’t be afraid to reach for a compressor when it suits the job better. Now insert your chosen compressor into the channel in question. 3. to see if that makes it easier to find a decent fader level. Yes: If you have indeed fixed the balance issue. No: If the balance problem is still there. gain reduction meter shows at least 6dB of compression on the loudest peaks. and you can then make any necessary adjustments next. just try gradually bringing the threshold back up and seeing how little compression you can get away with. and this is where the automatic processing offered by a compressor can be the better or complementary option. Set Threshold And Make-Up Gain. making fast. Multing can solve a lot of problems on its own. An option here if you want to work quickly (which is likely when working with a alrge number of tracks in a mix) is to start with a likely-looking preset setting in your compressor. 2. even it if makes the result sound rather unnatural for the moment: the important thing is to keep concentrating on the balance. you may have solved the balance problem without any further adjustments necessary. Feel free to completely max out the control if you like. robust changes to the controls as you sweep around and keep your ear out for the sweet spot where it just seems to Page | 15 . Be bold and loose with the controls here. There’s no need to give it too much thought: it’s just to get you in the right ballpark with minimal tweaking.
  just put any EQ after it in the processing chain. When compression does solve your balance problem. and how they’ll work slightly differently to each other on the same material. There will be times when although you’ve found an appropriate balance through heavy compression. One is that other effects can introduce more noise into the system. So essentially. set it up as before and see if this one works better. The other point is that putting the compressor first in the chain also gives the other effects a better signal to work with.Get That Pro Sound . changing the level of certain frequencies) can alter the way the compressor responds to the input material. Remember the different types of compressors discussed earlier. If you still can’t find a static fader position that works. Should Compression Be Pre. With experience. you might wonder where you should put the compressor. try a few different compressors or presets. In these cases. just switch to a new compressor or preset. so pre-compression EQ (i. the processing isn’t doing nice things to the instrument’s sound. you will end up amplifying that noise as well. for two reasons. so if you put the compressor after those effects. albeit in carefully specified frequency regions. if you’re happy with the way your compressor is working. 6. that’s the time when pre-compression EQ makes sense. as the difference between having the compressor before the EQ section or after it can be surprisingly large.e. ask yourself a follow-up question: do I like the subjective ‘sound’ of my compression? If not. Equalisation is primarily about changing signal levels. processing or automation work to reach a decent balance. But if you find that frequency-based problems make it difficult to achieve the compression you want. you’ll soon build a shortlist of personal favourites for different instruments.or post-EQ Placement Of Compression In The Effects Chain If you use a chain of multiple processes on an instrument. 5. Perhaps it’s making the performance feel lumpy and unmusical. or altering the tonality in some undesirable way. Page | 16 . See the box below on EQ. In this common scenario. Typical Compression Scenarios – Taming Excessive Peaks or Routine Dynamic Range Reduction – The Importance Of The Ratio Setting Here are a couple of examples of typical compression scenarios you’ll encounter at this stage in your mixing.The Ultimate Guide to Compression naturally come together.or Post-EQ? A key exception of the above advice is when chaining compressors and EQ. Post-compression EQ won’t have any effect on how the compressor behaves. it is usually best (all other things being equal) to put it first in the signal chain. you probably need to do some other Compression. EQ And Effects Chains: Which First? Pre.
  5:1) the overshoots are nudged gently back towards the Threshold.Get That Pro Sound . Compressing with a low ratio can be used to gently squeeze the dynamic range such that it will maintain its position in the mix balance. Scenario 2: Preserving the internal dynamics of a part with a lower ratio. That way you can set the threshold just above the level of the majority of the bass part. and then a high ratio to clamp them down to a level more consistent with those remaining note bodies. louder sounds are effectively stopped in their tracks. and it will then kick in at full force only when the over-zealous slap notes hit. and then adjust the Ratio control accordingly. for instance). whereas at higher settings (12:1. In contrast to the above example. In scenario 1. Setting a compression threshold above the majority of the note peaks allows you to compress just the rogue slap note. so in this case you want your compressor to put up a proper fight and all but stop the input signal from exceeding the threshold. Increase the ratio higher. However. You want your compressor to act more gently on signals overshooting the threshold level. Still too much slap? Increase the ratio to clamp down on the peaks more firmly. but if you used a normal moderate compression you wouldn’t be able to contain it as well as you might like. It’s a compressor’s Ratio control that allows it to tackle these two contrasting problems. overshoots are clamped down on without mercy. but where the overall dynamic range is still making it difficult to balance in the mix with a static fader level.The Ultimate Guide to Compression Scenario 1: Taming excessive transients/peaks by isolating them from the remaining notes with the threshold setting. and then find a Threshold setting that caused the gain reduction to kick in only on the excessive peaks. though. At the highest Ratio settings (some compressors offer infinity:1). Page | 17 . lower ratios tend to be better for instruments which have good musical dynamics. Imagine an electric guitar part where there are no dramatic level spikes. but simply have too wide a dynamic range. lower ratios (up to about 3:1) will fix balance problems in a more natural-sounding way. effectively setting how firmly the compressor reins in signals that overshoot the threshold level. What compressors do is reduce the amount by which a signal level exceeds the compressor’s threshold level. unable to cross the Threshold at all. you’d set the Ratio up fairly high to start with. if the ratio is set too high. and the gain-reduction will stamp down much more firmly on the offending level spike. preventing it from leaping out unduly within the mix. At low Ratio settings (something like 1. a high ratio is just what is needed. so that you can set the threshold just above the level of the softest notes and then subtly squeeze the whole dynamic range down to a more manageable size. For routine dynamic-range reduction tasks like that in the second scenario though. the compression will iron out the part’s internal performance dynamics and render it unmusical. Once you’d done this. So for our first scenario. that will squeeze the entire dynamic range just enough to position the part easily within a mix balance. you’d listen to ascertain whether you’d solved the balance problem.
  leaving it a bit flat and lifeless – so try to turn up the Ratio control only as much as is required to get the balancing job done. Synths and Guitars. at once. but also more general low-ratio dynamic-range reduction on the same sound? The answer is by chaining more than one compressor in series. Now you can apply that creative/character compression to all the drums. You may want to simply adjust the compressor that you’ve already used on a given part. for example. Page | 18 . set up groups or busses for each main section of instruments and tracks – usually one each for Drums and Bass. and Vocals (including the appropriate combination of lead. you might start off with a fairly low ratio of around 2:1 and then set the Threshold so that gain reduction happens for all but the quietest notes. though.The Ultimate Guide to Compression In scenario 2. If you’re wondering what order to put the different processors in. The best solution is to try both ways and choose the one that best resolves the balance. This is a huge benefit. but be careful that you don’t undo your correctional work from before. and start applying ‘submix compression’. insert a compressor on the group. Now’s the time to reach for the tube and analogue-modelling compressors. increase the ratio to reduce the dynamic range further. Stage 2: Using additional compression for colour and creative dynamics Having resolved any pressing balance problems. with one compressor instance. With the Threshold in roughly the right place. you might now want to go back to certain tracks that you feel could use additional character.Get That Pro Sound . as the dynamics processing applied to a group of instruments in this way has the effect of ‘knitting’ or ‘gluing’ them together – one of the great strengths of compression in a mix context. and lets you dedicate each specific compressor to a different task. However. at this point if you haven’t already. If some quieter notes are still too indistinct. FX. route the individual tracks to the relevant group or buss. when you consider putting two compressors on every main track. This is quite common in practice. A better option would be to simply insert another compressor after the first. punch or energy. backing and harmony parts). and of the drums and bass together. Why not just max out the Ratio control? The danger is that if you turn it up too high. you’ll iron out the important performance dynamics that make the part sound musical. things can get overly complicated (and very processor-intensive!) very quickly. So. the answer isn’t quite as clear. At this point you might be thinking: what if I needed not only to apply high-ratio control on the loud peaks. dedicated to providing extra character and dynamic shaping. It’s especially effective for enhancing the groove of the drums as a whole. This is why it’s such a good idea to. you could then turn back to the Ratio control and tweak it one way or the other to achieve your static fader level.
  Get That Pro Sound . so the balance between the transient and sustain phases of the drum will remain pretty much unchanged. If you then set the release time very fast. B. The typical approach is to push the Input or Output/Make-Up Gain to drive the compressor (or the next device in the chain. reducing the gain swiftly. The drum transient will be de-emphasised relative to the overall snare sound. massive dubstep snares. or overdrive the drums compressor in or output: this usually adds a certain ‘crunch’ or bite to drums that makes them feel really powerful. the gain-reduction will reset very little during the drum hit itself. Fast attack. it’s a great way to introduce some authentic vintage character to programmed or very clinical-sounding drum parts. The Waves Renaissance Compressor is a good choice for this role because it allows a large excess of Make-Up Gain to be applied. you’ll be able to create many different effects from a standard snare hot. The Page | 19 . such as tape. and so you can get away with relatively extreme settings.The Ultimate Guide to Compression Using A Compressor For Character/Distortion One of the most effective areas in which to apply character compression is drum parts. which tends to clip the output. breathy snares and snappy pop/R&B snares. almost any processing on drums comes off as some kind of ‘effect’. just make sure that the compression/distortion is consistent (ie. Fast attack. low threshold) across the whole sound being processed. As already mentioned. Armed with these parameter combinations. an analogue-emulation plugin or a second compressor or limiter) into clipping. but if you do want to actually apply compression at the same time. the gain reduction will also reset very rapidly — well before the drum sound has finished. Character Compression Case Study: Working With A Snare Drum Let’s mess about with a single snare drum hit to demonstrate the sorts of character changes you can make with compression. You can also try inserting two Renaissance Compressors in series. (Don’t worry. such that the lower-level tail of the drum hit won’t be compressed as much. instead resetting itself mostly between the hits. It’s worth noting that the effect can be achieved without actually applying compression (since the main task for the compressor here is to simply raise the gain level). Of course. slow release – Overall level change. A. in this case it sounds more like a boost in the upper-mid frequencies than ‘distortion’ per se – it also affects the balance between the attack and the ring of the note in a generally useful way). which allows more variations in drive color. from tight and punchy rock snares. A popular technique is to intentionally clip. because we are using it like EQ: for a color change. fast release – Transient suppressor Set the attack time to fast and the compressor will respond quickly to the fleeting initial drum transient. little character change If you partner your fast attack with a slower release.
  Get That Pro Sound . Remember. effectively increasing the level difference between the transient and the rest of the snare sound. and then rebalance the parts while listening through the compression – rather than applying it as a last step. Bare in mind that the compression will affect the balance of the drums in relation to each other. Compressing Submixes Once you’ve routed all the individual tracks to it’s corresponding submix. Instead of reaching for a multi-band compressor to compress each of the frequency bands individually to maintain the balance. it’s a good idea to pick sounds that are at least close to what you want to begin with – but this shows you that with compression you can sculpt your sounds in a completely different way to EQ. things will always sound better if you apply moderate compression at several points between the individual tracks and the master output. which can be tricky at first. and potentially all from the same snare sample/recording! Of course. this means some interplay between setting the basic drum sounds and mix and setting the right overall compression. and also get the bass and drums grooving like the single rhythm unit we want. you’ll find that some of the drum transient begins to sneak past the compressor before its gain reduction clamps down. if you then set the attack slower.The Ultimate Guide to Compression compressor in this case is simply making the level of each drum hit appear more consistent. In practice. for example. slow release – Transient booster However. But the Page | 20 . and more transient level — all with the same compressor. A gentle approach on the submix here can lock in the sound of the kit with it’s ambience/reverb. possibly together with the bass and the drum reverbs. so it may be easier to ‘mix into the compressor’ – insert and set the compressor first. it’s much better in the long run to simply compress in sections over the course of the entire mix. more consistent hit level. hard-compressed sound. than if you just plaster a final stereo mix to the wall with heavy compression right at the end. and when they apply as much compression as they want all in one go. they get the side-effect of the compression unbalancing their carefully constructed mix. So working mostly with the attack and release controls we’ve achieved three different balance results — less transient level. C. Slow attack. Drum Submix Compression A great place to start is usually to compress a submix of the drums. Submix compression is also useful because it’s another point in the mix where you can maintain your relative levels and frequency balances – one of the reasons that people resort to multi-band compression (see below) on the master buss is that they’re trying to do too much at the final stage. using compression in a mix is all about the cumulative effect – if you’re after an exciting. you can compress the instruments in each submix together.
  One solution is to have the master output compressor set up right from the start of your mix. and it should be possible to get the compression turning on and off in time with the beat. by ‘tuning’ the compressors attack and release to work in rhythm with the tempo and spacing of the drum hits. Even if you’ve compressed individual tracks and submixes gently up to this point.Get That Pro Sound . Set the fastest attack possible. The relationship between the two controls will give many sound variations. if your mix compression is too heavy. This way. The pumping or breathing effect is dependent on the attack and release controls. and release to the slowest. With the release now on a fast setting. it can still be easy to go too far and mess with the overall dynamics. Stage 3: Stereo Mix Compression Toggling the Master Output Compressor On & Off During Mixing Having a stereo compressor over the whole mix is generally a good idea. so you will tend to get audible pumping of the higher frequencies every time the kick sounds. all the balance Page | 21 . Here’s how: large amount of gain reduction indicated on the meters. for example. Rhythmic Compression On The Drum Submix Another reason for compressing the drum submix is that it allows you to introduce or accentuate the overall groove. and ‘mix into’ it in the same way as already mentioned regarding submixing. you’ll probably just be fighting it the whole time. This does require setting up appropriately moderate compression right from the beginning – try a ratio of only 2:1 at first. Now move the release control through its range to its fastest position and note how the sound changes. While it can be useful to know what the final compression will do to the mix. You’ll hear rhythmic compression effects at fast release settings. because ultimately the compressor responds to the peak signals regardless of frequency range – the loudest/peak signals are generally to be found in the lower frequencies (as it takes more sonic energy to create a ‘loud’ bass sound than a higher pitched one). 1. with a 2. Advanced compression: Sidechaining & Parallel Compression If you’re going to use any advanced routing or compression techniques. when compressing a whole mix with a regular stereo compressor. use the Output/Make-Up Gain to set the output level back to something appropriate for you overall balance. 3. now would probably be the best time to implement them (more on this in the next chapter).The Ultimate Guide to Compression results and sense of control you gain over your mix is absolutely worth it. move the attack control for slower attack times and 4. Once you’ve got a sound you like. Start with a high ratio and low threshold so that the signal is heavily compressed. but monitoring through it when mixing is hard work. note how the sound changes. Leave it bypassed until the mix is almost finished.
  The Ultimate Guide to Compression adjustments you make along the way will not be undone when you get to the master output. how much to compress each band in relation to the others. when you’re generally trying to get everything gelling together. Multi-Band Compression As already mentioned. normal compressors tend to introduce a ‘pumping’ effect with anything more than very subtle settings. the result being a louder. The reasons why multi-band compression is not always recommended are that there’s even greater capacity for error than with regular compression – knowing where to place the crossovers. which are then compressed separately. as the name suggests. regardless of frequency. for example. Page | 22 . not undoing the good tonal balance you’ve achieved up to that point etc. The downside is that it can be hard work monitoring constantly through a mix buss compressor. when working with material that covers a full (or at least large) frequency spectrum. yet the compressor will attenuate the entire output by the same amount based on the loudest parts. Multiband compression. This way you can compress the lower frequencies harder than the highs. I would never say ‘don’t ever use multi-band compression’. There’s also the idea that splitting up the full mix into separately processed parts again at this late stage. tighter mix which doesn’t pump or sound squashed. double-checking that it’s helping and not getting in the way. and there will be times where you’re fighting against it in your efforts to balance and apply other processing to parts – so make sure that you regularly bypass the mix buss compressor as you mix and monitor.Get That Pro Sound . uses ‘crossovers’ to split the full-bandwidth input sound into sections of smaller bandwidths. all take some skill and experience. is not going to bode well in principle. such as a complete mix. If you find that no matter what you’re doing you’re not getting the results you want with a submixes/stereo compressor on the mix buss strategy. because you’ve taken the additional compression into account all along. you could try a multi-band compressor. just be aware that if you construct your mix well in the first place you won’t need it other than in exceptional circumstances. This is because the lower frequencies which tend to trigger the compressor will normally be doing something quite different to the higher frequencies.
  and then applying make-up gain. particularly the sort of heavy compression you might want to use on drums and vocals. But above the threshold the compressed signal will be progressively reduced and add hardly any additional level to the mix. Page | 23 .. This allows you to pass many tracks through the same compressor. producing a straight 6dB increase in level. Once you know the principles of parallel compression. Thus the low-level signals are brought up and the whole thingl sounds louder and ‘fatter’. the trouble is that the effects of compression. It works for any instrument (try it on drums.The Ultimate Guide to Compression Advanced Compression Techniques Parallel Compression Also called ‘stealth’ and ‘invisible’ compression (as well as ’New York’ compression because of where the technique first became popular). the compressed version dominates at low signal levels and the uncompressed version dominates at the audio peaks. there are a couple of different ways to go about setting it up. Neither is better: they are just different ways of reaching the same result. The dynamics in the dry signal are preserved while the compressed signal adds body and character to the overall sound. This is fine in theory. bringing them down closer to the low-level passages. At levels below the compressor’s threshold the two signals will combine. but as we’ve spent much of this guide discussing. and of course saving on processor power. and insert the compressor on the duplicate only. What we need is compression that only operates on low-level signals (where the details are). and the added character can really bring a track to life. rhythm guitars and of course whole submixes). handy for fattening related tracks together. vocals. are quite audible. Parallel Setup 1: Simply duplicate (aka ‘mult’) the audio track that you want to parallel compress. making the quiet sections louder without affecting the loud sections. Put another way. you can get more overall dynamic range reduction with fewer audible sideeffects. and send a bit of each of the instruments to be parallel compressed to that buss. Parallel Setup 2: Set up the compressor on a group/buss. parallel compression is a lot simpler to set up and get good results with. The answer is suprisingly simple: you mix the uncompressed signal with a compressed version of the same. than it is to understand why it works… Just to recap.Get That Pro Sound . Compression works by reducing the high signal levels. The result is a form of compression where the sound is reinforced only where it needs it: therefore. one of the main uses for compression is to increase the apparent loudness of an instrument or mix. which often means a compromise between getting enough compression and not losing the dynamics of the original sound.
  Using a fast attack and slow release removes all the transients from the signal. adjust the MakeUp Gain of the compressor to get the most suitable level of compressed signal for your needs. Apply 3. on the other hand. Set the Attack as slow as possible and the Release as fast as possible. Typical Parallel Compression Starter Settings We’ve already looked at typical settings for various key instruments. Parallel compression settings can vary quite radically (it’s something of a stylistic effect as much as anything). If the processing isn’t quite working for you. try tweaking the compressor’s release time. with a shorter re- Page | 24 .The Ultimate Guide to Compression Parallel Setup 3: You can use the mix or wet/dry knob if your compressor plugin has one. At this stage it’s also a good idea to toggle the mute button on and off. to compare the subtle sonic properties of the processing with the untreated original signal. but here you’re likely to want to use – and can get away with – much more extreme settings than if you were compressing normally. so that all the transients are getting through and the initial punch is still there. Example: Parallel Compressing The Drum Submix 1.5-1dB gain reduction) the kick and snare as you normally would. Hard Knee setting. Turn off the Auto Gain mode if your compressor model has the option. Mix engineers often go for a more characteristic effect by using a high ratio and fairly fast attack and release times while mastering engineers. and while listening back to your mix set the Threshold low enough that you’re getting about 20dB of gain reduction (as we said. to strike the right balance between compressed/uncompressed signals. a good general-purpose / subtle setting could be: Start with a 2:1 Ratio. as do different ratios. strong compression (10 or 12 dB of gain reduction and a Ratio of between 4:1 to 8:1) and bring them up underneath the originals. However. toms. snare. but the compressor releases instantly when the signal drops below the Threshold. you can go more extreme than with normal compression). depending on the exact effect required. lightly compress (0. through another parallel compressor and bring that in as well. Mult the kick and snare to another group: this will be our parallel compressed group. to give the kit an overall sound. as this can have quite a pronounced effect on the sound of the processing. but not the rooms or overheads – Other Considerations Different attack and release times create different effects. fastest (0ms) Attack and Release around 350ms. 2. However. Then send all the main dry drum tracks – kick. First. Finally. might use much more gentle ratios and longer release times for a more subtle ‘massaging’ of a full mix.Get That Pro Sound .
  The Ultimate Guide to Compression lease time. Compressors With Sidechain EQ If your compressor does have a Sidechain Filter or built-in EQ.Get That Pro Sound . When you understand the creative and technical possibilities of using the sidechain in dynamics processing it opens up all kinds of creative possibilities. Raise the filter frequency of your EQ such that only very high frequencies are allowed to pass — try 7kHz as a starting point — and reduce the compression threshold to retain similar levels of gain reduction and you’ve essentially got an enhancer. but in others there will also be a whole host of side-chain processing options. as well as new solutions to typical mix problems. This is how you can use a kick drum track to make a synth pad pump in time with the music. Just set a high-pass filter and sweep up until the frequency balance of the compressed signal is more what you’re after. saturation plugins and distortion units – for example. particularly if you try processing complete mixes (refer to the earlier section on multi-band compression for the explanation of this). used to add psychoacoustic high-frequency ‘sparkle’ to sounds). An extension of this filtering technique allows you to simulate the effects of a typical Enhancer processor. you’ll find that in practice it’s Page | 25 . If the compressor has an external sidechain . Which leads us nicely to: Sidechain Compression What Is A Sidechain? The sidechain. and these become particularly apparent when a compressor is pushed to the kinds of more extreme settings used for parallel compression. you can use the characteristics of one sound source to compress another. or key. If this isn’t a desirable side-effect for your purposes. bitcrushers and really distressed effects can add something amazing when mixed at low levels under the original dry part. you can create that distinctive rhythmic ‘pumping’ effect. most commonly some kind of EQ or filter. EQ + Parallel Compression = ‘Custom Enhancer’ One thing you may notice when experimenting with heavy/parallel compression is that it can make the bass frequencies of processed audio seem weightier. A yet more convenient way of implementing EQ on a compressed signal is to engage the Sidechain EQ on the compressor itself. On some compressors this will appear as an extra input labeled ‘Sidechain’. Try all kinds of compressors.or key – input. Just remember that it’s easy to overdo: use the bypass regularly. Also remember that different compressors have different characters. you can use insert an EQ before the compressor to adjust how the compressor is responding. or you’ll end up with a tinny sound that’s unnecessarily tiring to listen to. is the signal within a compressor which monitors the input and controls the output level.
  Rhythmic Pumping Sidechain Compression Probably the most recognisable creative use of compressor sidechains. When you are having trouble getting that elusive punchy.Get That Pro Sound . 4. It’s now accepted to hear a lot of modern electronic music – techno. but adjust depending on how much you want the track to pump. first create a 4/4 kick drum pattern – the basic House pattern – and loop it for as long as your track is. it’s expected of a lot of modern productions. powerful sound. but it really does add so much energy and excitement and. EQing the sidechain may be the answer. your input source. It’s easy to overuse the effect.The Ultimate Guide to Compression much more than just another type of EQ: instead of simply cutting or boosting different frequencies. creating a pumping effect that can be very effective for adding apparent energy and dynamics to a dance production. and select the kick drum track as 3. and EQ and compressor plugins in series don’t seem to be delivering the results. house and trance particularly – with the full mix pumping dramatically. 1. Page | 26 . Once you’ve got the amount of pumping about right. 2. this is the effect created by applying heavy compression to a fairly constant. You can mute this kick drum track if you already have a kick in your mix: it doesn’t need to be audible in the mix as it’s only there as a source for the sidechain of a compressor that’s operating on another sound. there are no rules here! Start with quite extreme settings: as usual. sustaining sound (like a synth pad or bassline) with a compressor whose sidechain is being ‘fed’ by a completely different sound – usually a kick drum or kick/snare drum submix in modern electronic music styles. you can allow different frequency bands to control the amount of compression applied. To use this technique. This will emphasise the pumping nature of the effect. to a greater or lesser degree. as the compressor has more dense.As far as settings for the compressor itself. return to the Ratio and Threshhold and adjust them to taste. try inserting a reverb before the compressor. sustained sounds to breathe in and out. Every time the kick hits the synth dips in volume. Insert a compressor with an external side-chain capability. the higher the Ratio and lower the Threshold the more extreme the overall compression will be. and perhaps more of spot effect. To make the effect even more dramatic. Try a fast Attack with a medium Release.
  allowing them to punch through a dense mix. 4. On The Attack Try not to use the fastest Attack on everything if you can help it: many instruments. A better approach is to simply listen. The Relationship Between Attack/Release Times & Gain Reduction An important consideration when tweaking and finetuning compressor settings is that changing the Attack and Release times will affect the amount of gain reduction that you get for a given combination of Threshold and Ratio settings. Compressing Effects Returns Don’t forget that effects returns – particularly reverbs and delays – are just as fair game and in need of compression as any of your individual instrument tracks. Also try listening back to each compressor with the track both solo’d and in the context of the entire mix: as ever.e. if your delay doesn’t quite fade away as you’d like. do some A/B comparisons and decide which you like best for different effects. don’t get too hung up about using ‘exactly the right settings’: suggested settings are only ever hypothetical averages. 2. For example.Get That Pro Sound . or you want to bring up and draw out the sustain of a reverb tail. it’s necessary to describe things in milliseconds and other particular numeric values. 5. what sounds subjectively ‘better’ can be very different depending on whether you’re listening to it in isolation or in a mix context. will stand out more with the extra ‘front’ you get from allowing the initial transient/attack through a compressor unscathed. and as such only a rough guide to how a specific compressor might respond in practice. the snare drum track) in your current mix. Using Compressors In The Real World: When To Use Eyes And Ears When talking about compressor settings. it’s common to keep adjusting Threshold and Ratio controls alongside your Attack and Release. 3. a sound with a short transient and very little sustain) might completely bypass a compressor that has a long attack. For example. a side-stick sound (i. seperately from the instrument that fed the delay) may give you the control you’re after. Always remember the interrelated nature of all the controls and settings on a compressor. Page | 27 . Bass instruments can really benefit from the extra definition provided by a good attack transient.The Ultimate Guide to Compression Bonus Compression Pro Tips 1.e. The Fast Way To Build A ‘Personal Favourites’ Compressor Plugin List Which compressors in your collection are the best for which instruemtns and situations? Insert multiple compressor plugins on the same track (e.g. particularly guitars. even if its level shoots way over the compressor’s threshold. paying attention to the character differences between them. However. and solo them one at a time. For this reason. then compressing the return (i. Once you’ve programmed a few of them.
  isn’t necessarily a problem. you’re not compressing. if it only goes down to 3dB. the signal might never pass below the Threshold long enough for the level to begin to return to normal. Be Aware Of Your Release Time Setting Release is the time it takes for the amount of gain reduction to return to zero after the signal has passed back below the compression Threshold. to any significant extent. The necessity of covering that additional 3dB will audibly distort the initial transient.at some point in the course of the track while the instrument is playing. just lower the fader! ‘Compression’ implies a constantly changing amount of gain reduction. the compressor has to go all the way from zero gain reduction to the full 12dB. the gain reduction meter must indicate zero. anti-side-effect compression. When setting the Threshold. This. 7. adjusting the Attack and Release controls by ear. How fast it dances up and down is up to you but. a short fast Release time will give you a more audible compression effect. This is very useful for offering visual clues as to whether the compressor is doing what you want. you’ve actually only got 9dB of compression/ gain reduction. and how fast the compressor is responding with it’s current settings to the input material. Imagine a scenario where an instrument plays occasionally with silences in between: this is where over-compression is most likely to happen. The amount of gain reduction is controlled by both the threshold and ratio controls. If it’s not moving. 12dB is achieved. Don’t forget that after initially setting a low Threshold in order to hear clearly what effect your other control adjustments are having. then you haven’t applied 12dB of gain reduction. Suppose these controls are set so that the desired amount of gain reduction e. but you also won’t actually get as much real compression. The problem is that. with the gain reduction meter visibly dancing up and down. in itself. 30dB of gain reduction. when the instrument starts to play. The other 3dB could have been achieved by simply lowering the fader. You don’t need a compressor to get any amount of gain reduction – if that’s all you’re after. if you want value-for-money compression. 6. In some instances. for example.The Ultimate Guide to Compression and focus on finding the best balance with the fewest unmusical side-effects. but not 30dB of compression.g. one situation when you will want to trust your eyes is when reading a compressors gain reduction meter: this will show you how much actual compression is being applied.Get That Pro Sound . does it ever go all the way down to zero? If it doesn’t. This should be fine shouldn’t it? Look again at the gain reduction meter. many users have an idea of how much gain reduction they want to hear (and see on the meter). While the instrument is playing. Set The Threshold Only As Low As Is Actually Needed To Avoid Over Compression This is related to the tip above. This leads to rule number one of gain reduction . A slower Release will lessen the audibility of the compression. Having said that. unless you’re after a particular effect you should generally draw the Threshold back up as far you can get away with for lean. otherwise the minimum Page | 28 . The result here would be. Try this out and you’ll hea it.
  8. even if you’ve already done some sensible multing. But listen carefully. The guitar has a nice. between song sections. which means that it’s likely to deal with this particular balance problem more effectively. Increase these and the compressor will react more slowly. The Attack and Release controls provide a remedy here. The reason why the compressor in our example isn’t doing the job we want is that it’s reacting too fast to changes in the signal level: the Attack and Release times are too short. So although you’ve sorted out your overall balance problem. you can’t find a good fader setting for the track in the mix. because it’ll track longer-term level variations (such as those between our verse and chorus) rather than short-term ones (such as those between the individual strum transients and the ringing of the guitar strings between them).Get That Pro Sound . but you find that you have to turn the fader down whenever the player digs in more during the chorus. rather than just reducing the level differences on the ‘macro’ scale. while the Release specifies how fast the gain reduction resets or ‘releases’ the signal. Simply compressing the the bass at this point is unlikely to solve the issue. ‘micro’ level differences between the attack/ transient and sustain parts of each strum. you’re not fundamentally changing the balance of the instru- Page | 29 . leading to the distortion of transients that follow silences. At this point it’s tempting to simply settle for a compromise between dodgy balance and unmusical processing side-effects. Macro vs. because no matter how much you reduce the dynamic range of the sound.The Ultimate Guide to Compression reading obtained shows wasted gain reduction and over compression. because they determine how quickly the compressor’s gain reduction reacts to changes in the input signal level: the Attack setting specifies how fast the compressor reacts in reducing gain. the compressor is also evening out the much shorter-term. you quite reasonably insert a compressor to even out the level difference between song sections. or how you set the Threshold. natural sustain that works really well when it’s at the right level in the mix. when you actually start dialling in compression settings you find that. However. Micro Compression: Setting Correct Attack & Release Times Imagine a scenario where we’re mixing a song with a strummed acoustic guitar. So. You’ll commonly find that if you bring the level of the bass up to where it’s cutting through adequately in the mid-range. because your mix is probably trying to tell you something: this situation requires something different than can be achieved with simple compression on it’s own. it’ll also now be swamping everything else at the low end at the same time. the unacceptable side-effect is that the impact of each strum is softened. or the instrument’s sustain is over-emphasised. 9. For example. When Compression Isn’t The Magic Bullet: Knowing The Limits Of Compression There are often situations where no matter which compressor you use. balancing bass instruments in a mix is a classic tricky situation where you’ll typically need to use more than compression to achieve professional results.
  there’s another particular scenario where compression is only half the answer: in increasing apparent loudness. with vocal fader automation.The Ultimate Guide to Compression ment’s frequency content. and the nice ‘soft clipping’ type of harmonic distortion generated by valve designs (and valve-emulating plugins) rounds rather than clips the peaks – which conveniently increases perceived loudness. It’s much better to address a problem like this with EQ first – or possibly even replace the bass sound completely. Another very common occasion where compression can’t provide a complete solution to mix balance issues is when dealing with very critical tracks – lead vocals are a common example here. As powerful as compression is as a creative and technical tool. You can set up increasingly elaborate/flexible versions of this configuration: for example. so by using a compressor followed by a limiter. The compressor evens out the overall level of the signal.Get That Pro Sound . although by this point you might discover that compression is no longer required at all. One of the significant characteristics of compression is that it works optimally over periods of at least tens of milliseconds: If you try to make a compressor respond too fast by using very short attack and release times in your quest for total loudness). or adjust your arrangement to make space for the midrange element of the bass. if it’s a synth bass. As with many things. A limiter will only introduce soft clipping on high-level signals. moment-to-moment level tweaks manually. 10. there are limits to using a compressor for loudness. and you start getting distorted lower frequencies (kick drums and bass in particular can appear to lose bass content with Attack times under 50ms). The answer can be to use a compressor together with a limiter. getting the best results from compression also means understanding it’s limitations. it’s simply not intelligent enough on it’s own to deal with extremely dynamic. the compressor begins to respond to individual waveform cycles rather than the greater overall shape of the signal. as any that do spill through will be reined in by the limiter that’s next in the signal chain). Using A Compressor Followed By A Limiter For Real Clipped Punch Following on from the previous tip. you Page | 30 . in series. not clipping the peaks but bringing them to to a more uniform level (you don’t have to worry about compressing the peaks anyway. You’ll be able to tell when you’re on the right track with EQ when it starts getting easier to find a suitable fader level for the bass: then you can think about compression again. This is just the sort of raw-but-optimized audio a limiter likes – it simply has more signal to work it’s soft clipping magic on. you can allow each of them to play to their time-based and amplitude strengths. If you try to keep these parts up-front and audible in a mix entirely with compression. detailed and complex parts like a main vocal usually is. they’ll usually sound over-processed. it’s more sensible to keep the compression within musical-sounding limits before dealing with fine. for achieving maximum overall ‘loudness’ gains without unwanted side effects. which can make all the difference. Clearly. Limiters work in microseconds.
  In such a series-parallel configuration. Page | 31 .The Ultimate Guide to Compression might very well want to combine the compressor/limiter series with the benefits of Parallel Compression described earlier. the limiter soft clips the peaks. and the result of that whole process is added back to the uncompressed signal. If you want to go further still you might add an EQ after the compressor. so that you can choose the specific frequency range to be affected: with this setup you can add just the right hint of distortion without going over the top.Get That Pro Sound . It might sound like overkill for some. but the result is highly controllable enhancement over a wide range of levels. the compressor first smooth’s out and brings up the levels. particularly in the mid-range.
  to plotting and implementing an overall compression strategy. and don’t forget to check out the GetThatProSound blog regularly for new posts. If you haven’t already. to some advanced techniques for creating refined.. I really hope this ebook will be helpful in your next sonic adventures .The Ultimate Guide to Compression Conclusion Throughout this guide we’ve covered everything from quickly and effectively setting up compressors for a range of typical duties. That’s what it’s all about. more tips and more ebooks. There’s a lot of information packed into this guide and it’s unlikely you’ll digest it all simply by reading cover-to-cover: by all means do that first to get an overall view of what’s covered. have this guide in front of you and open (either in a window next to your DAW or printed out on your desk): this way you can refer to it as you work through the techniques and see how they work in the context of your own music.com. George Robinson Get That Pro Sound Page | 32 . Best of luck. but after that you’ll probably get the most benefit by using it as a quick-reference resource as you develop your abilities.. polished and ultimately professional mixes.let me know how you get on with it at george@getthatprosound.Get That Pro Sound .