OP's Note:

This articled has just arrived in my mailbox, and I've copy-pasted it in its entirety here. Opinions are not mine (I wish they were), and they offer a great overview on how compressors work. Newbie or Audiosexers with a mileage can beneft just the same from this well thought-out article.

Enjoy.


Which Compressor Plugin Should I Choose for My Mix?
October 18, 2018

Learn the different types of compressors and when to use each one while mixing. In this guide, we'll level out which compressors are which: VCA, FET, Optical, Variable-Mu and digital compressor plugins; increase your threshold of compression knowledge!

By Mike Levine




Compression is hugely important when producing and engineering music, both for dynamics control and sound coloration. Because there are so many different compressor types, it can be confusing to decide which one to choose for a given situation. The aim of this article is to give you some clarity on the different compressor types and talk about how they're typically used.

Once you understand the strengths and weaknesses of different compressor types, it's a lot easier to know which one to choose in given situations. The suggested applications here are only guidelines, based on how various compressors are typically used, but there's no saying that you can't go counter to them if it works for your music.

Let's jump right in, starting with the main categories of analog compressors. Because so many plugins are built to emulate the characteristics of these classic designs, it's useful to know a little bit about how they work, what their strengths and weaknesses are, and how they differ from each other.

VCA Compressors

VCA is an acronym for "voltage-controlled amplifier," which is the component at the heart of the circuitry in this type of compressor. A VCA compressor reacts to peaks that are above the user-set threshold. VCA compressors are known for having fast response and are therefore a good choice on peaky, rhythmic or transient-heavy material.

Many VCA compressor designs include precise control of a wide range of compression parameters including threshold, ratio, attack and release time, makeup gain and sometimes knee. This abundance of control makes VCA compressors versatile jack-of-all-trades dynamics processors. Depending on how you set them, VCAs can be transparent or not to the original tone & harmonic characteristics.


The Waves dbx 160 was created in collaboration with dbx and emulates that compressor's unique sound and characteristics, with some added "plugin-only" features.

For transparency, it's important not to set the attack too fast because it can squash the initial transients of a sound, which tends to make it seem more audibly compressed. If you set the threshold too low and the ratio too high, you'll end up compressing more than peaks, and it can seem "over-compressed." Not only that, VCAs can cause some serious distortion when pushed too hard. If its accurately modeled, a digital emulation of a VCA compressor will exhibit similar characteristics to the analog hardware version.

Among the most renowned VCA compressors are the API 2500, which can be used as a buss compressor or on individual sources, the buss compressors built into SSL consoles, and the dbx 160. The latter has been a longtime go-to compressor, especially for drums, adding its own unique snappy character to the drum transients.

Good for:

• Compressing drums, percussion and other transient-heavy sources
• Adding punch
• Smoothing out peaks in a transparent way—for example, restricting the dynamic range of a vocal or instrument performance without squashing transients
• Buss compression—both master and subgroup
• Virtually any compression task, because they're so versatile

Not as good for:

• Adding warmth or color

In this video, Grammy-winning mixer Tony Maserati (Beyoncé, Jay Z) applies an SSL G-Master Buss compressor to a hi-hat loop, and explains some of the subtleties of working with compression and what he feels it adds to recorded music and audio:



FET Compressors

Like the VCA, FET compressors are solid state but use a particular kind of component called a "field-effect transistor," which was designed to emulate the behavior of tube circuitry. FET compressors offer even faster reaction times than VCAs. Many FET compressors have no threshold control. The amount of compression applied is governed by the combination of the amplitude of the input signal, and the setting of the input level control. The louder the input, the more signal gets compressed.


Waves CLA-76

A FET compressor is not what you'd choose if you want transparent gain control. It imparts a distinctive sonic fingerprint on the source material. Probably the most famous FET compressor is the Urei 1176, which is heard on thousands of classic albums and offers an aggressive, fast compression that's great on vocals, drums, guitars and more.

The CLA-76 is a plugin emulation that not only mirrors the control set of an 1176 but also offers you the option to switch between models of two different iterations of the well-known compressor.

Good for:

• Adding an aggressive sound and excitement to vocals, drums, bass, guitars and more—from a little extra vibe to super pumpy
• Limiting, due to fast attack time
• Parallel processing; their ability to create extreme compression is useful when you're blending it in with the uncompressed sound

Not as good for:

• Transparent compression

Optical Compressors

Compressors typically split your input signal into two parts: One is sent through a detection circuit, which determines how the compressor will act, and the other is the audio that's operated upon by the compressor and sent to the output. In an optical compressor, the detection circuit is unique; the audio signal is turned into light, which triggers an electro-optical sensor that governs the amount of gain reduction. The response of this setup is smooth and transparent. Unlike other compressor types, hardware optical compressors have fixed ratios, typically 3:1.

Perhaps the most famous optical compressor of all time is the Teletronix LA-2A. Technically referred to as a "leveling amplifier" (hence the "LA" in the name) it combined both electro-optical circuitry and a tube amplifier for a smooth and pleasing compression that was particularly useful on vocal tracks, but also great on other sources. The LA-2A hardware unit is ubiquitous in commercial studios and has been heard on countless recordings. It is available in faithful plugin form as the CLA-2A.


Waves CLA-2A

The LA-3A model offers similar functionality but without the tube circuitry, giving it a cleaner sound. This one is also available as a plugin: the CLA-3A.

Good for:

• Transparent compression
• Adding warmth and sheen to vocals, guitars, basses and other instruments (especially true with the CLA-2A)
• Improving the vibe of vocal tracks

Not as good for:

• Controlling hard transients
• Aggressive-sounding compression

In this tutorial excerpt, hear two varied styles of compressors applied to a lead vocal, one after the other. Once the CLA-2A is applied, notice how it brings the vocal's overall level up significantly without feeling overly squashed, and adds a helping of harmonic richness and warmth:



Variable-Mu Compressors

A variable-mu compressor is based around tube circuitry that produces smooth compression with pleasant coloration. The circuitry achieves its attenuation through re-biasing of the tubes. It's not a super-fast acting compressor, so it’s not as good for transient control, but it adds warmth and depth to just about anything; you can get nice-sounding aggressive compression if you push the input and threshold controls to extremes.


Waves PuigChild 670

The most legendary iteration of a variable-mu compressor was the Fairchild 670 Tube Limiter (which also came in a mono version, the Fairchild 660). Original Fairchilds are incredibly rare and really expensive. Fortunately, there are excellent tube emulations including the PuigChild 660 and 670 plugins, which provide realistic emulation of the original Fairchild units.

On the original and the emulations, the attack and release controls are linked together under the Time Constant parameter, and you can choose between six different pre-set attack/release time combinations.

Good for:

• Adding warmth, color, and fatness to any source
• Parallel compression
• Adding glue on the master buss
• Mastering limiting

Not as good for:

• Precise attack and release control (on Fairchild emulations specifically)
• Controlling hard transients

Non-Emulative Digital Compressors

While analog-modeled compressors are very popular, there are plenty of compressor plugins on the market that aren't designed to simulate the sound and behavior of specific vintage units and have capabilities that take advantage of the precision and versatility of digital technology.


The Waves eMo D5

For example, the Waves eMo D5 Dynamics plugin uses the Waves' Parallel Detection technology, which is only achievable on a digital plugin, to provide incredible precision, plus other one-stop-shop dynamics controls. The H-Comp plugin offers the ability to dial in different types of analog-compression characteristics in ways that wouldn't have been possible in a hardware unit.

The Waves Renaissance Compressor is another example of an original design digital compressor. It offers the versatility of both “Warm” and “Smooth” character types, which engage low-frequency harmonic warmth, or bypass it for transparent compression more true to the signal’s original tone. Also built in are “Electro” and “Opto” behaviors, which respectively engage more quick or slower release times.

Good for:

• Its versatility
• Extra features not possible on analog units
• Comprehensive and precise control

Not as good for:

• Emulating specific hardware compressors

Multiband Compressors

Multiband compressors, which allow you to focus on several user-definable frequency bands, are used most commonly on the master buss and in mastering situations but can also be quite helpful in a mixing context. They're a bit more complicated to use because you have to set crossover points to define the frequency zones and configure the compression parameters for each one independently. They can be beneficial for many types of tasks that single-band compressors wouldn't be appropriate for.


Waves C6 Multiband Compressor

By giving you the ability to target specific frequency areas for compression, multiband compressors can not only control dynamics but can be used for frequency manipulation as well.

Waves offers three different multiband plugins: the six-band C6, four-band C4 and the Linear Phase Multiband Compressor.

Good for:

• Targeting specific frequency bands for compression
• Mastering
• Smoothing out sources—such as vocals—that change in timbre when they get louder or softer during a mix
• Reducing problem frequency areas in a source

Not as good for:

• Simple operation

In this video excerpt, multi-platinum mixer Lu Diaz (Jay-Z, Beyoncé, DJ Khaled) details his process of getting a lead hip hop vocal under control before adding color and flavor, using the C6 Multiband Compressor and other digital-style compression plugins:



Low-Level Compressors

Another type of compressor that exists only in digital form is a low-level compressor (a.k.a. "upward compression"). Like a standard downward compressor, it reduces dynamic range but does so by bringing up soft sounds rather than lowering loud ones. If, for example, you have a vocal track where the singer gets too quiet on some words, you could use the low-level compressor to bring those words up automatically.

You can also use it to accentuate parts of a signal that were recorded lower. So, for example, if you have a room or overhead drum mic, you could accentuate the room sound with a low-level compressor.


Waves MaxxVolume

Waves offers a few different compressors with low-level capabilities: MaxxVolume and the MV2. These models both include not only low level compressors but downward compressors as well, allowing you to squash a source from above and below if you want to. MaxxVolume also includes a noise gate and a leveler.

Achieving good results on an upward compressor typically requires that you use subtle settings. Heavy settings will not usually yield pleasant sounds. Typically, you'd use a low-level compressor on individual sources, although they're sometimes used on the master buss to thicken the sound a little. For example, the "modern" limiter mode in the Abbey Road TG Mastering Console features an original-design VCA-based compressor that incorporates some low-level compression elements, perfect for a modern mastering sound.

Good for:

• Bringing up low-level aspects of a track such as room sound
• Reducing dynamic range by raising quiet sections

Not as good for:

• Adding warmth
• Controlling transients
• Peak reduction
• Parallel compression

Squeezing it all in

As you’ve seen, there are quite a few types of compressors to choose from. They each have their strengths and weaknesses that once you’re familiar with, makes it easier to choose the best one for any situation. Often there will be more than one type that can successfully get the job done, and your decision will come down to the particulars of the music.

It’s useful to experiment with different compressors on a range of sources to get first-hand knowledge of how each one sounds and behaves. The sooner you get a grasp for what the various types can do, and the particular characteristics of the ones you own, it will become second nature to pick the one that’s right for your track in any situation.

Want to dive deeper into compression? Explore more compression tips, techniques and tutorials here.

See the full range of Waves compression plugins.

 

In many ways an excellent round-up but totally omits the word 'leveling' which is easily one of the most important functions of a compressor (particularly optical levelers).

 

Agreed, but I guess nowadays I'm more into automating offending peaks so that compression is more gentle. I personally like Hornet Autogain, and it's dirt cheap and 50% off this weekend (No, I'm not affiliated to them. I just love them for their sincere pricing). Waves Vocal and Bass Riders have always been kind of difficult for me to set up. It must be me, though.

 

Trigger-happy duped post. Sorry.

 

Last edited: Oct 19, 2018

As well as it doesn't tell why Waves sells 465 different compressors (which would interest me more than those basic stuff that I already know), but I appreciate share.

 

so they can write articles like this and make people think they need all 465 different compressors and throw all their money at one of the most overrated plugin devs of all time :D

 

Does this come in a pdf? If so could somebody perhaps post a link for us to download and read through offline? Thanks in advance

 

make rtf document in windows

 

basic for the most but he goes into which one for what too...

 

Pretty sophisticated use of Multiband Compression for Cleaning Hip-Hop Vocals with Waves 6C:

I think Tony Maserati was the first one to talk about this technique using the C4:

I think cleaning a source with multiband compression or dynamic EQing before you start sclupting the sound is the most non-destructive way to do it. Back in 2014, when I first watched this, my sense for hearing/feeling conflicting frquencies and my knowledge of compression parameters weren't as well developed as they are now, so I wasn't really able to apply these techniques in a useful way. It definitely takes a lot of experience to make it look as easy as they do – this is not for beginners.

 

optical comp

i missed that point in the past.....thats some magic shizl

i always knew , studios are magic places , but that some units have internal sorcerer's , was new to me

 

Last edited: Oct 20, 2018

them waves have 465 comps...really ??

economic growth cant come from nothing

 

I think it is 38. 38 compressors included multiband and channelstrip compressor. 40 plugins in the dynamic plugins category. That's I know for sure (comps, gates and deessers).

But hey 38 comps. I could use a different waves compressor on every single track in a lot of my projects.

 

Just to think I only go for the CLA2A and the SSL Bus Compressor. I'm missing a world out there.

 

just like the pro's
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but hey kidding beside..its not a bad decision to use a lot of different comps...
but hhmm...yeh ppl...most of users use only few waves plugz but want the whole bundle for just in case and to impress customers..or not to impress...to meet the industry standarts...

bit like wearing right labels in school or you not cool enough...he he

but on the other hand top notch easy to go or/and in depth tool box , still and ever

but when i would had to spend the money i would spend it at plugin boutiqe and melda which pricy but much more worthy maybe..
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i would be interessted of which plugins which came out sincerly are true new effects...not effects from 1950 in another matrix or engine when you letin me call it like that...besides new inovative mixxing tools

 

Last edited: Oct 20, 2018

but what for waves should earn plugin grammy a long time ago is : the ultra simple one click help pluging manualbutton in corner of each plugin...all devs should do this like that for ever

 

Thanks. This is something everyone who does not think this way would benefit from.

For some time I have been weeding out product that that sort of works from that which does what is expected of it.
EQ, Compression, Leveling, Limiting, Channel Strips, Reverb, Delay etc...

Personally prefer the Black Rooster LA compressors over the Waves LA series.

Side note. The new AR TG Mastering Chain actually very useful. Does what is expected of it.
Moved away from the Scheps Omni Channel & replaced with the SSL Duende Native series.

 

wait until you find out how a spring reverb works then :D

 

melda will get my money too. waves is great, but definitely overrated. they have worked hard to make themselves an industry standard, like logic and apple have done, but they do not offer anything special. melda, however, definitely do!

 

Oh that's easy, they have to fill all the holes in their market offering that other vendors blow into it by actually innovating. So, for example, UAD started with a Fairchild 670, so Slate had to have one, so everybody and their dog had to have one, so Waves had to have one. That way there's no excuse for going to another vendor, and there are 11,397 different Fairclone vari-mu compressors on the market.

Vari-mu's a bit of a dog in my opinion, except maybe the Manley one, which is bit like a car crushing machine. Most soft Fairchilds are a bit sproingy in an not entirely useful way, but that's what happens when you slavishly ape old audio gear. Wave Ren Compressor - now that's a good machine. But hey, if you can't make your own mind up about stuff, what hope is there copying people who can? That way you just end up on X-Factor crapping yourself.