Audio Compression: How to get a tight Sound - MIXING AUDIO | Marco Silvestri | Skillshare

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Audio Compression: How to get a tight Sound - MIXING AUDIO

teacher avatar Marco Silvestri, Sound Engineer & Music Producer

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Taught by industry leaders & working professionals
Topics include illustration, design, photography, and more

Watch this class and thousands more

Get unlimited access to every class
Taught by industry leaders & working professionals
Topics include illustration, design, photography, and more

Lessons in This Class

15 Lessons (57m)
    • 1. Introduction

    • 2. What's a Compressor?

    • 3. Dynamic Explained

    • 4. A bit of History

    • 5. How does it work?

    • 6. Serial Compression

    • 7. Limiting

    • 8. Sidechain

    • 9. Parallel Compression

    • 10. Types of Compressor

    • 11. How to use it?

    • 12. Applications

    • 13. in Practice

    • 14. Comparison

    • 15. Assignments

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About This Class

Welcome to this episode of the Mixing Audio series!

In this class I will teach you everything about the Compression.

Learn your way into compression, exploring the most actual compression techniques and technologies, to give your crafts the edge you need to make them outstanding and unique!

In this class you will learn:

  • Compression, what it really is and how why was invented;
  • How does it work and how to set-up correctly ratio, threshold, attack time and release time;
  • Serial compression;
  • Sidechain compression;
  • An intro to Limiting;
  • Parallel compression;
  • How to compress all the tracks in a song;
  • How to choose between VCA, FET, Optical, Variable-MU and Digital Non-Emulative compression;
  • The various applications of the compression.

This class is not software specific. You will be to apply what you have learnt in your favourite Digital Audio Workstation.

You can access the other lessons of the Mixing Audio series here:

  1. The Pre-Mix
  2. EQ and Equalization
  3. Compression
  4. The Reverb

Meet Your Teacher

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Marco Silvestri

Sound Engineer & Music Producer


Hello, my name is Marco. I am a Sound Engineer, Music Producer and Video Colourist, with more than a decade of international experience in the field. I started my journey in the audio world in Italy, and after working with several studios and production houses, I moved to Ireland and then to Kenya. I have worked with corporates, established and upcoming bands, theatres and live events.


Here my playlis!:

Mixing Audio

The Premix: in this class you'll learn how to move to first steps in starting your mix right; The EQ: Equalization, Equalizers and Filters. Learn how to change the frequency content of your tracks! Compression: playing with dynamics is easier said than done. In this class, you will learn everything you need to learn about Audio Compres... See full profile

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1. Introduction: Hi, everyone. My name is Marco Silvestri and I'm a sound engineer based boat between Europe and Africa. Welcome to my new skill shop class. About mixing audio today. I'm going to teach you about audio compression ratio. Trey, Shal attack time won't be a Mr Animal. I will show you Our simple is to set up a compressor And how effective is within the economy? A mix. So hold onto your hats and let's get started. 2. What's a Compressor?: do you? Compression in its totality represents a topic fool of myth and false notions. Before getting our hands dirty, I must explain your couple of things so you can fully understand compression and know your compressors. First of all, the compression I'm talking about is not the wine related to the various file formats. That's cool data compression, and it would be addressed in this class. As a matter of fact, another compressor can be defined as a single processor, which modified the relationship between its input and its output in order to reduce the dynamic range or signal understanding that will significantly make your life simpler when choosing right compression. You want to apply? Let me expound to you what dynamic is. 3. Dynamic Explained: dynamic or dynamic range can be defined as the difference in tomorrow levels between the loudest and the soft. Despite of a given signal. Generally, the higher the dynamic range is there, each other signal will appear not only Reacher, but also more emotionally engaging, more defined. Morial. The less of the dynamic, the more one dimensional and anonymous the signal will be perceived and also the less of all tings mentioned prior. The exaggerated and quite frankly murdering use off compression to favor the loudness over the OD dynamics leading toe, a phenomenon called Loudness War. I'm explaining the loudness war and its impact in the music pocket in the related mastering class. 4. A bit of History: the dynamic range compression or audio level compression is well known. Since the broadcasting industry was created at faster A compressor was used as a tool rather than something that could have improved the quality we are going to deep in our radio works and broadcast, we can imagine a radio wave as a simple sine wave did. Your signal is actually broadcast using that sine wave by modulating it and change the properties off that radio wave. This process is called in cording really receive eyes. For example, the one now archives will peak and record that radio signal by extracting the audio from it . Okay, UK, Why am I telling you this? Well, that can be an issue in the signals, including that issue is known as over modulation off a modulation can happen when our modulating signal such as music, exceeds some citing levels when it's being included into the radio waves. Ultimately, this can cause the transmission signal to distort and failed to transmit the signal. Originally, the compressor was created with the scoop off protecting the signal we wanted to transmit, but it using the dynamic range of it and avoid the over modulation. Well, it turned out that this effect sounded pretty cool. It made things sound louder, punchier and with more character, and it also reduced the need of engineer to constantly right Frieda's. Then we started associating that compressed sound with a nice and polish charity sound. A new chapter off the history of sound was made. 5. How does it work?: before using aerial compressor. Let me give you a schematic visual and simple explanation off most off the perimeter that defined his device. I say, Dahlia, that a compressor is a serial process sort that changes the relationship a k a. The ratio between it seem pretend it's output. In this diagram. Let's assume that the X axis represents input levels and the UAE output levels in a normal situation. So when a compressor is not compressing, the ratio is 1 to 1, meaning that for every one unit in input, there is one unit of output. If we change this relationship, for example, by setting operation off 2 to 1, it means that for every two units of input, there will be one unit of output. This value can be set through a switch with fixed values or continuously through a knob, depending on the compressor were using. But a compressor would be a big smarter, and this, in fact, we would also be able to set a threshold, a point from which the compressor will apply the desired ratio. Still following hours Kim, we can set a threshold at three units, meaning that from 0 to 3 d racial will be 1 to 1 for every one unit of output. We need one unit of input. Then, once the compressor will read, four units of input will apply. The ratio is selected. Let's assume a Toto one demanding more units of input to produce the same output increment . These will allow us to decide how much of our dynamic range we would need to reduce threshold ratio are not the only perimeters that come in Andy. When using a compressor order. Important values are attacked time every least time. The attack time defines how fast shoot the compressor compress after the signal goes above the threshold. This is important when we're dealing with tough transients or when trying to preserve some off the head of the signal. The least time, on the other hand, deter mines out faster. The compressor should go back today, 1 to 1 ratio. Once the attack time has elapsed and the signal is below detraction, it helps to determine the amount of leveling that we want to achieve on the tail of the sound. Here, we can see as an example what could possibly happen toe a square wave being processed with different attacking really settings. This wave is the result of the original wave processed by a compressor with a very long attacking release time. Here it is the opposite. Instead of a long attack and release, the times are very short. But the truth is in the middle. Jokes aside, this is our medium. Attack and release could possibly look like the correct setting off. Attacking a list time is essential when trying to manipulate transients. Additionally, in some compressors, you may find a perimeter cold name, which basically sets this muteness off the ratios transition. It can be set with a switch, either soft or we don't know in decibels. The more the decibels taken by the need this motor, the transition will be. This is useful when dealing with instruments, a situation that requires a proportional and transparent compression. Last but not least, is the makeup gain. Basically, with a compressor, we pushed down the level off the higher picks, actually reducing the loudness passive. The makeup gain is used to recover that loss of loudness, bringing back ah more tied, solid and level sound. It's also important to mention that in some compressors, especially the old school, once the perimeters are much less. Sometimes we can only find an input and an output knob. Basically, in these models, we do not set the threshold. But we increase the input level till the signal reaches that threshold. But do not let yourself be deceived by their simplicity. Some of these models have survived the test of time and that became legends. To summarize on what I said above you can think in these times the threshold is where what we compress. The ratio is how much we compress the attack in the least. Time is when we compress Dinneen is the house moodily we compress. 6. Serial Compression: maybe the fast and most immediate application off the compression for any user is called senior compression. This technique seem Pouliot effective. It expresses the real nature of a compressor, it being used as an inserting a track. It is also possible to pile up different compressors in a serious one after another and delegate to each compressor a specific task like team dynamics at warm and character to a sound or limiter signal or combined compression without a signal. Processors like distortion and the cue to achieve surprisingly and expected results. But we're moving too far from the scope of this class. Let's now hear the effect of audio compression on vocals way from the landlord in remembrance Off the War. Two Brothers hadn't made it on. Joe could not forget. I'm just going to apply some gentle compression to tame it a bit and balance it. Old Joe had first received it in 1954 a prison from the landlord in remembrance off the war Two brothers hadn't made it on. Joe could not forget, but the contents off the glass remained his best hope yet passed the glove lost on spill, a drop the history held women. It can never be. Report. Pass a glass past glass. Old Joe had first received it in 1954 prison from the landlord in remembrance off the war. Two brothers hadn't made it on Joe could not forget, but the contents are The glass remained his best hope yet. Passed the glove the last time. Spill a drop. The history held women. It can never be report. Pass a glass past glass. Simple and quick. Let's listen the way President froth landlord in Remembrance of War two brothers hadn't made it on. Joe could not forget, but the contents off remained his best yet. Old Joe had first received it in 1954. A prison from the landlord in remembrance off the war. Two brothers hadn't made it on. Joe could not forget, but the contents are The glass remained his best hope yet. Passed the globe. I'd see nice and published 7. Limiting: on their on dimensionally meeting. Delimiting is a special kind of compression used to limit the signal below. The desired threshold is possible by setting a very higher Asia with a shortest attack time possible. While the release can be said contextually to decisional process is mostly using mastering and life. Although also in mixing and find some useful applications, we can try and apply. SUMMLY meeting on this is near. I am assured that by limiting it, I could gain some useful decibel of headroom for my drums. Let me show you. How did you he ate It became a bit fatter, but it also lost some of his Chris Penis. In exchange, I've gained a couple of decibels. Also, Look, it doesn't matter what happens, but Disney A is not going past nutrition. Good boy. Now that we have a rough idea now, compression might sound and look. Ideally, it's time to see orders. Compression techniques, together with compressors, technologies 8. Sidechain: basically we can simplify. The compression is an automated level reduction perform according to the perimeter that we set. What if we construct a compressor making it reduced the level of one instrument according to deliver off another instrument? This possibility is called side chain. In this General Ian option, that's some outboards and plug ins have is very useful when it comes into the resolution of a clash between two instruments forest on Sabes, Geeta and the Kick Drum, or to create a synergy, which is that abundantly needy em like, for example, the kick drum and some pads. Let's have a look in detail. Normally, a compressor like any other signal processor will also take the audio input as a trigger. As a specific case, let's take a basically Tom and the kick drum. We might need to reduce the level of the bass guitar every time the kick drum hits. All we have to do it manually for every beat, or we'd have to instruct our compressor to compress the bass guitar every time the kick hits. To do these, it's important to have our trigger, the kick drum and the track. We want to process the bass guitar separately. Then we open a compressor which supports side chain on the bass track, which week our values and reactivate decide chain. Often, it's indicated with the symbol of a key. After that, we select which bus should act as the side chain keep last but not least, do not forget to send the key conduct bus, preferably at zero db and in pre fader mode, it Walla decide changes made to give you a better idea. Now it sounds, let's make it in May Digital audio workstation and and Let's Liston after him before focused on interaction between the base and the kick. And now, to make it pretty obvious, let's try to side chain there who's to get out with a kick in 1993 and then back down. Nice defector. His technique is so versatile that can also be used to morph the son you have into something completely friend. You can basically side chain everything. The imagination is the limit, but let's not forget that in this context, it's use in a more conservative way. Please refer to my class about the cute to discover the difference between conservative and creative 9. Parallel Compression: as the last compression technique. Explain in this video, I love to share with you parallel compression. Yes, I know a compressor is ah signal processor, which should be used in a serial fashion. So saying pile compression is an oxymoron. The exploiting off this technique in music is known since 1977 when the article compressor and limiters they are uses and abuses was published in a magazine called Student Sound. But parallel compression gain is glory in the nineties, when it was used abundantly by the engineers off the Motown are recording Studio, based in New York. In fact, barrel compression is also known as New York compression. These allows the reach of a good compression level, especially on the soft part of a song, without squeezing the sound too much and retaining part of the original dynamic. Let's see how it works. To achieve parallel compression, we need to send a copy of the signal. We want to compress toe a compressor with a very high compression factor for this particular task. Old school compressors would really do miracles. After the compression, I'd advise the application of us might take you to the compressed signal. Smiley because it dips in the center almost during a smile as the last step would just sum it to the original signal. Do not worry about phase issues, as the majority of modern digital audio workstations off are on automatic militancy compensation. My personal preference is to make the two signals into a separate track before they reach the rest of the instruments. Battler compression is a technique a generally apply on vocal stems, bass guitars and rhombus is for this example. I will apply it on the dramas. Here is the original track, and here the coffee I apply every compression on one of the two signals and afterward I applied is mainly a. Q. Let's listen to these evilly compress track. Well, it does not sound quite pleasant. Let's play together with the original and mix the two. - These ground became warmer, fuller and more solid. Let's listen to the comparison. - Exactly what they wanted India's was the parlor compression. In a natural, you could also think outside the box and process that parallel signal in different ways. The keys to experiment until you find something that really works for the music you're producing 10. Types of Compressor: we saw the tree main compression technique serial side chain in parallel but does not rule . It's also crucial to choose the right compressor food right task. In fact, even in the world off mix in the box, there are different kind of compressors, which compressed signals using different principle and as a consequence, give different wants to the sound. Let's observe them together. The V C A, which means voltage controlled amplifier, is a jack of all trade of compressors. Having a full set off barometers allows the user to customize a lot of aspects of the compression. However, in my personal opinion, it lacks character and warmed fete acronym for field effect transistor can be taught off as an aggressive rendition of the tube technology. The bare minimum amount off para meters will make the use of focus exclusively on the distinctive sonic fingerprint off the fed compressor. It could be used to add excitement to a signal or can be employed in apparel configuration . However, if you're looking for transparency, stay away from it. An interesting compressor is the optical, also known as Opto. It's perhaps one of those motors compressors, but the detection security, based on The transformation from moderate light makes it also one of this Louis. It's effective as a leveller compressor and also nothing more texture. It's, however, not ideal to use it for an aggressive compression or to treat material with hard transients . Valuable immune or very immune. It uses a peculiar characteristic off the tuba called Cuba biasing. Basically, the user cannot directly control their issue, but it varies in proportion to the input signal. The louder they input them order issue, it is able to fatten up and that color to nearly everything. It's also used in parallel configuration and toward glue on the master bus. It might not be the best on her transcends or when a precise attack and release times are required. Last but not least in importance is the digital known emulated compression with modern digital audio technology. It's possible to create algorithm that offer are very precise compression, which in some cases extend the usual functionality of a compressor. These make the digital compression very versatile. In all kind of situation, however, is not optimal. If you're looking for character 11. How to use it?: Now that you know what is a compressor? Our It waxes different types. There is still a fundamental question. How do we use it? Let's see together, out to set up a compressor and in which ways I can use it how to set up a compressor. Which perimeter should I move fast? Everything has a logical reasoning and nothing is left to the case. The initial set up of a compressor should sonically express the most obvious degree of compression reachable to reach the scope. You should put the Trecia all the way up so initially no compression will take place. Also, the ratio should be all the way up. We really want to squeeze out every sonic beat of our plugging our outboard, keep the attack and release a shortest possible. Any control regarding peak or RMS or knee should be set contextually to the sound treated generally a pick option and the hard me a preferred. We need to determine the extent of the treasure in with those girl that racial down till we find what we exactly want to compress. Many compressor will start to distort As soon as the signal overshoot. These will pass identifying the portion of the signal we want to compress from my personal experience, I can tell you that you should keep your treasure even a bit lower from the point of discord. As you're just their issue, it will be more gentle once we know the extent of nutrition. Is it time for the ratio toe? Go down till we find it sweet spot. The attack is made longer here. After that, we also just the realist time. These method will usually get you very close to what you need. After that, fine tuning usually follow, but that is left to your common sense, your taste and your years. So before going into a fully fledged practical session, let me summarize the application of a compressor. 12. Applications: making sounds begin Fattah due to the ability to bring the low frequencies in front accent waiting. The mere details off sounds by bringing up this morning wants is of our performance, like the fingers moving on the strings of a guitar. Or the small lip movements off a vocalist balancing and containing levels by reducing the gain of a signal once it overshoots the threshold. Loud inning by taming picks and reducing dynamics, giving the user some bedroom to increase the levels. Applying dynamic movement by creating an organic synergy of different sound sources through the use of the side chain. For example, imagine to have a pod. We can assume that the courts will play at a reasonably the same level by feeding the party into a compressor and feed the kicking to the side chain. We will apply some movement on the tail of the pod for shaping the dynamics by attenuating the decay of a signal with a long release time. These will emphasize the attack transient over sound, creating a more snappy and farm heat 13. in Practice: Are you ready for some practice? Here we are in pro tools. You can access a no load this session from the link I gave you in the first class. I will be applied compression as if I'll be alone in my studio. Let's go back down, - back behind Handed up, down lengthened Britain again Hold on a dig a la brea and then back down Soul plays the law that pills to the length and breadth of Britain on around one more again, drop history within. It can never be. Two years ago, the glass was that his week passed around as usual with comedy and graced. His picture still hangs proudly about never. Two years ago, the blast wave never two years ago, the glass was on his way in 1990 rolled on optical memory and then back down. Toll booth lengthen wrecked Britain on round one. More again, like three minutes. Never two years ago. Down the toll booth, if never down the toll booth length and breadth of Britain on round one. More again, if three minutes never down toll booth length and breadth of Britain on round one more again way Boom, I think, is pretty decent. Let's listen and compare 14. Comparison: Lord, remember, brothers had intimated on Joe Could not against on 10 Gloves remains yet in 1973 story in on future trusted deputy. Many times Stage died but still drink drunk three and then back down Wait ! Passed around, as usual, with comedy and grace. His picture still hangs proudly above the fireplace on the way Joe received it in 1950 people present from the landlord in Remembrance. Doctor War two Brothers hadn't made it on. Joe could not forget, but the contents off the gloves remained his best hope yet You can never be. He passed it in 1973. Unconvinced Odeon off future trusted deputy dance around the country to Reggae's Ghar. On many times it's staged I, but still the drink got drunk. Three within it. Never in 1990. Hold on up Big elastin Re and then back down Toll booth Never Go. Glass was that his week passed around as usual with comedy and graced. His picture still hangs proudly above the fireplace on the wall on the way. - So in the first row version, with just a bit of premix things, arbiter stable. Some instruments are all over the places and the vocals is not farm as they want, in fact, is even thinking in some points. The compressed version, on the other hand, is more stable. Key tracks like the voice I brought in the foreground, we don't masking. The rest of you also noticed the interaction between the kick drums and the bass guitar. 15. Assignments: Why don't you apply some compression by yourself? Just don't know the files have prepare for you. Load them into your digital your station. Do your compression and send me back to result. You'll find more details in the project up. That's all for today. Do not forget to follow me here and on my social media. Do not miss any of my classes and in the meantime, let's rock.