Compressor types, designs, and styles
Today the plugin marked is flooded with countless plugins for music compression. The quality of the new ones is usually higher due to competition and modern DAW hardware but some old classics are still good and CPU efficient.
For this article, we have chosen some example plugins from every overall compressor type and design category. A mix of old and new.
What is music compression
Music compression is a technique for controlling dynamic range in music material. Like equalizer, It is used a lot in music recording and mixing. Compression in sound means reducing the dynamic range for more level control.
Often used to give an impression of loudness and impact or just to get too soft parts up without moving the fader.
- 1176 FET
- A classic solid-state FET from 1968 originally designed by Bill Putnam. A design with character.
- Known for its fast attack and fast release.
- The LA2A is a famous opto(light sensor) ideal for vocal compression where speed is not a factor. Tube-Tech CL1B is a more versatile opto-design with more controls.
- Other vintage hardware emulations
- Besides the FETtypes Vintage 2254, Variable Mu and LA3A are other famous designs.
- Are other musical vintage hardware designs emulations
- Modern hybrid or new, not emulation specific designs
- This category has lots of great creative tools that just do the job
- Bus compressor
- Bus compression types are designed for mix bus or master bus compression
FET transistor-based solid-state comp type with a lot of character. Great for vocals and bass.
- Waves CLA-76
- IK Multimedia Black 76
- Pulsar Smasher
- Stillwell Audio The Rocket
Other hardware modeled types
Klanghelm MJUC variable mu
- Klanghelm MJUC Variable Mu
- T-Racks VC 670 Variable Mu
- Waves V-Comp 2254 emulation
- Waves CLA3A
Waves LA2A vocal plugin
The optical comps are based on light and has the slowest attack and release times but the appealing sound makes them good for vocals. The LA2A is "The" vocal compressor.
- Softube Tube-Tech CL1B
- IK T-Racks Opto-Compressor
- Waves CLA-2A
- Cakewalk CA-2A
- IK T-Racks White 2A
Fabflter Pro C2
Modern Hybrid or clean digital compressors are designs that do not emulate any hardware units. In this design category, you find the most versatile.
Some plugins are:
- Fabfilter Pro C2
- Izotope Neutron 2 and 3
- Waves H-Comp
- Waves R-Comp
SSL Native bus Comp.
The 2 most famous bus compression solutions are probably the SSL Bus Comp and API 2500 stereo.
- SSL Native Bus Compressor
- Waves API 2500
Here are short highlights of some of the plugins.
Waves CLA-76 with the longest attack and shortest release for percussive material
The 1176 compressor is probably one of the most emulated compression types for its character and recognizable sounds. A fast attack/release time FET design and the Waves plugin is just one of many.
Used a lot for rock vocals, bass, and drum bus with all buttons in for smashing room mics or bus.
Pulsar Smasher 1176 compressor type plugin with modifications
Pulsar Smasher is a new 1176 with only 2 essential knobs. This plugin was free when it was released. A different 1176 with a lot of automatic control behind the knobs. The original had a confusing time knobs with 1 for the highest and 7 for the lowest times.
Width fewer knobs to worry about it might be recommended for beginners.
- Universal Audio UAD 1176
- IK T-Racks Black 76
Originally designed for vocals opto-compression has a clean distortion-free gain reduction.
CLA-2A from the Waves CLA bundle
A classic opto design and famous for its vocal performance. Very simple controls and automatic times.
Softtube Tube-Tech CL1B
Softtube Tube-Tech CL1B - a famous opto-comp.
A great plugin emulation of one of the best opto-designs. A versatile plugin with more time control.
- Clean compression
- Sounds not far from the hardware version
- Clean compression
- Stereo metering
New digital designs
This is potentially the best category for high-quality compression tools, creativity and new features.
Fabfilter Pro C2
Fabflter Pro C2 - one of the most versatile dynamic tools you get
This is a versatile and clever plugin. A swiss knife plugin that can handle any audio material from vocals to the full mix.
CPU usage can be a bit high.
Neutron 2 and 3
Izotope Neutron is another swizz knife channel strip. It ha 2 serial single- or multi-band options with side-chain. One of the most versatile plugins but do not expect character but clean compression.
It might have too much CPU overhead for just using it as a simple compression of an instrument.
Waves Hybrid Comp is a mix between a modern and vintage compressor.
The PUNCH knob is unique and gives the material more initial attack and can be used for low attack compression to get some lost punch back.
SSL X Comp
SSL X-Comp. A versatile generic musical compressor
X Comp is SSL's version of a compressor that can do it all. It is versatile and generic like Fabfilter Pro C but with a lot less CPU usage.
This is one of the absolute best oldies. A plugin from 2008 but with a new GUI. If you configure it right it can sound like the Listen Mic compressor or the G Comp or probably any other compressor.
Klanghelm MJUC Compressor with 3 models
MJUC is a great compressor probably in the top 5 of all!
It might no be the CPU lightest plugin but it has great features and sound good:
- Build on a new Klanghelm framework
- 3 models
- British G type bus comp or fairchildish
- Timbre and Drive controls for tone and overdrive/saturation
- Reasonably low priced like other small company tools like Valhalla DSP
Stereo bus plugins
The stereo bus compressors are ruled by a few classic highlights but most of the new digital designs with no hardware emulation can handle bus compression too. Fabfilter Pro C2 and Neutron 2/3 are also designed for bus compression.
API 2500 stereo bus compressor
API Audio 2500 is one of the best know stereo compression tools and has several software emulations build on it. Waves API 2500 is one of them but UAD also has one for their UAD card platform. It is a characterful compressor.
Good for drums and bus compression.
SSL G-Series bus comp
SSL Native G-series console stereo bus compressor. A high-end unit
This is a plugin released by Solid State Logic themselves. In theory, it should probably the best and most original and it does indeed sound fine.
The max attack and min release is a classic for drum-bus but it also works on other busses in parallel or for kissing the needle on the master bus.
Other plugin emulations of the G-series compressor are the UAD, Brainworx BX Console, and Cytomic The Glue.
The Glue high lights
- A sidechain high pass filter for filtering the low end out of the listener circuit before compression circuit
- Oversampling options.
Cpu usage, performance, and latency
We have tested CPU usage and latency on a lot of compressors in Reaper Daw.
Some described in the article and others for reference.
If you care about CPU usage and latency they can be grouped into 3 categories
- Very low CPU use under 0.15%
- These are the bread and butter compressors that can be used a lot
- Low CPU usage between 0.10 and 0.30%
- These are ok too and can be used a lot
- Moderate to high above 0.30%
- These are for important tracks and some of them are actually mastering compressors
CPU usage and latency metering relative to an Intel 5820K CPU.
The PDC is Plugin Delay Compensation. In reaper, Delay Compensation is displayed as whole ASIO buffer sizes.
Naturally, the old plugins have the lowest CPU usage. Below 0.10% are Waves V Comp and Metric Helo Channelstrip 3 with older code designed for older CPU's.
Some compressors that stand out
As shown in the metering image above some plugins stand out when it comes to quality vs CPU usage.
- The Glue
- This is a great SSL G bus comp clone with some add ons
- SSL X-Comp
- Great versatile compressor with an SSL sound
- Waves CLA
- Ok 1176 Clone with a fairly low CPU usage
- Fabfilter Pro C
- Not the lightest but one of the most versatile and best
- Great plugin but heavy on the CPU
- Not advisable on all channels
What compression types are good for what
For vocals the slow attack plugins with opto or character are good.
Vocal plugins often have character or color
- Waves CLA-2A
- T-Tacks White 2A
- Cakewalk CA-2A
- Waves CLA-76
- Has the black and blue edition of the original hardware
- T-Racks Black 76
- UAD 1176
- Waves CLA-76
Bass plugins are:
- Tube-Tech CL1B
An alternative or addition to compression on bass is Waves Bass Rider. It fader rides automatically to a preset level you set and can be used in combination with compression for a very smooth bass track.
Plugins for guitars and other instruments
- Waves CLA-3A
- A plugin used a lot on guitars and keyboards/synths
Drum compression is often about attack smack, gluing together, or power impact. SSL have been known for their attack and smack on snare drums. The SSL G bus-comp and API 2500 is also a good bus compressor.
Good compression gives percussive material a snap and more power
- SSL 4000 Channel E and G
- This has a good attack for snare and kick and gives a snap
- SSL Native Bus
- Good for gluing the mix bus together
- Waves API 2500
- Good for gluing the mix bus together with a different character compared to the SSL bus comp
- A good FET model
- Max attack and high compression ratio like all buttons in for power
A plugin like Izotope Neutron 2 or 3 with 3 compressor stages is versatile enough to adjust to any kind of material and if it wasn't for the CPU load you could use it on 64 channels. It does not quite have the character of some of the analog models, which is why a mix of plugins is probably the best.
With DAW track-freeze and render-in-place, there is no limit to how many instances you can use though but you get the best workflow without freezing.
Should you buy them all
Having a toolbox with different audio compressors makes studio work and mixing easier. You could just use what is in your DAW but a few more are often preferable.
One modern tool like the Fabfilter Pro C2 or Neutron 2/3 is actually enough but it is nice to have some others like a FET and an LA2A type with a color and a sound.