Compression is a tried and true technique for taming unruly vocals, but how will it color the recording? Every compressor offers a unique tone based on the components, design, and settings used. But with so many possibilities at your disposal, it can be tough to choose which tool is right for the job. In this blog, we’ll break down some of the best compressors for vocals to help you find your sound.

Types Of Compressors 

Understanding how different types of compressors work and how they affect your signal is the first step to dialing in a great vocal sound. Compressors are typically categorized by the method they use to achieve gain reduction, from early tube and optical designs to modern FET and VCA compressors. Continue reading to learn more about the different types of compressors.

FET (Field Effect Transistor) 

FET compressors attenuate gain as a result of electrical charges in addition to the voltage. Known for being quick, bright, and punchy, FET compressors are often described as rich with some (desirable) distortion. FET compressors tend to be faster than others, making them ideal for taming peaks. Since they add some coloration, they’re not a great choice for mastering, but are great for helping rock and rap vocals cut through busy mixes. 

PWM (Pulse Width Modulation) 

PWM compressors use a high-frequency pulse signal to manage amplitude. Prized for their transparency, PWM compressors offer fast attack and release times, which makes them great for transient-heavy recordings. They’re subtle and great for styles of music that are less aggressive.  

Optical

Using light-dependent resistors, optical compressors are known for having smooth,  clean compression. As the input signal is increased, a light inside the unit gets brighter, triggering the resistors and causing heavier gain reduction. These compressors are slower in nature and react based on the average input of the signals received, which makes them great for smoothing out vocal recordings, but not so great for short, sharp transients.

Variable Mu

Technically speaking, all Variable Mu compressors are tube-based, but not all tube compressors are Variable Mu. For simplicity's sake, we’ll keep them in the same category here. The venerable Variable Mu is one of the eldest types of compressors. As the input signal is increased, the tubes apply more compression, resulting in a smooth, controlled sound. These are prized for that “vintage” sound and tend to add analog “warmth”  to the source. They tend to be a bit slower on the attack, so they’re not as responsive to transients. They’re great for adding glue and getting vocals to sit in the mix.

VCA (Voltage Controlled Amplifier)

One of the most common types of compressors, VCAs rely on a control signal to determine when gain reduction is applied to the signal. These are exacting, clean, and predictable, meaning they tend to color the source less than other types of compressors. VCA compressors are also the most flexible, typically featuring additional controls for dialing in a wide range of sounds. Generally, VCA compressors are best for taming peaks and pair well with slower optical or tube compressors.

Best Compressors For Vocals

Now that you’re familiar with the different types of compressors and how they can affect your sound, let's take a look at some of the most loved hardware compressors for vocals.  

Universal Audio 1176 

Created by Bill Putnam in 1967, the 1176 is one of the most famous and well-respected FET compressors ever made. With its fast attack and ample gain, the 1176 is known for its signature “squeeze” sound. Perfect for vocals of any genre, the 117 adds body and weight to the track rather than squashing it—kind of like giving that vocal a big hug. Many modern versions of the 1176 incorporate dedicated settings for “All Buttons In Mode”, which lets you engage all the ratio settings at once for an explosive and colorful sound.

There were 13 revisions made to the 1176 compressor from 1967 to 1973. Rev A is known for its low noise and high harmonic distortion. Unfortunately, there were only 25 ever made, so good luck finding this golden ticket! Rev AB is basically a more stable and controllable limiter with little else different from Rev A. Rev C notably has the LN and black front plate and is known to have a more linear operation because of the inclusion of the FET. Rev. D is slightly quieter, but overall very much the same. Rev. F has a different amp, giving it more output gain and the lowest harmonic distortion. There are many more Rev versions going all the way up to H, but the ones mentioned above are some of the most noted differences.

In 2000, the sons of Bill Putnam Sr. resurrected Universal Audio to make authentic reissues of the legendary gear from Urei. Their first release was the 1176LN, based primarily on revisions C, D, and E.

Retro Instruments 176

Another one of Bill Putnam’s designs, the Universal Audio 175B is revered for its groundbreaking vari-mu design. While vintage units can be difficult to come by, Retro Instruments’ 176 compressor remains true to the original design from 1961. Featuring a continuously variable attack and release, a vocal asymmetry tool, a wide range of side-chain and high-pass filters, and four compression settings, the Retro 176 combines classic sound with modern features. Known for its precise dynamic control, the Retro 176 remains smooth regardless of how much gain reduction is used, making it ideal for leveling vocals.

Empirical Labs EL8X Distressor 

This versatile VCA compressor offers a refreshing blend of vintage sound and modern features. Unlike most analog compressors, the Distressor incorporates several products into one by utilizing digital controls to switch between different circuits. Three modes provide varying levels of warm harmonic distortion, with Distort 2 Mode emphasizing tube-like 2nd-order harmonics, and Distort 3 Mode adding more 3rd-order harmonics, similar to analog tape.

The updated EL8X version includes new features like Stereo Image Link and British Mode (All Buttons In.) Besides offering a wide range of controls and unique features, the Distressor offers a warm, vintage sound by using a custom-designed gain control circuit. Capable of recreating the sound and feel of a wide range of classic compressors, the Distressor has become a studio staple over the last few decades. This is one of those compressors that’s got a lot of creative range and is so good, much like freshly baked cookies, you’ll probably want two.  

UnderTone Audio UnFairchild 670M II 

Don't let its replica status dissuade you, with its predecessor being about as hard to find as a guitar pick in a haystack (and much more costly), the UnFairchild is a great investment for anyone looking for the classic Fairchild sound. And while it may be an investment for some, it’s a worthwhile one. Fairchilds have a serious legacy and were instrumental to the Abbey Road sound.

The original had a few limitations, which UnderTone has thoughtfully addressed. Adjustments have been made to the circuitry to improve the lifespan of the tubes, and six new presets have been added, plus a host of new features including MS functionality, side-chain processing, a true bypass, adjustable DC threshold, and left/right balance. 

For vocals, the UnFairchild is great at taming the higher end of vocal ranges without sacrificing clarity, making them a must when you need the vocals to cut through a busy mix. Be fair to your craft and consider adopting an UnFairchild.  

Universal Audio LA-2A

A classic optical compressor, the Teletronix LA-2A offers lag-free, low-noise, gain reduction without an increase in harmonic distortion. Jim Lawrence, Teletronix founder, used photocells for controlling audio gain in the early 1960s. Thanks to this technology, he was able to achieve more stability and transparency than other compressors on the market at the time. His patent was purchased by Bill Putnam in 1967, and the rest is history. LA-2As are known for their smooth, almost creamy-sounding compression, and are commonly used in series with an 1176 to smooth out vocal performances. 

Manley Labs Vari-Mu 

The Manley Labs Vari-Mu is very flexible, making it great for vocals of any style. Similar to the legendary Fairchild 670, the Manley Vari-Mu uses vacuum tube rectified side chains to control the voltages, resulting in smooth, subtle compression. Known for making vocals pop with a modern, high-fidelity sound, the Vari-Mu brings out the high-end in vocal performances without adding any harshness.

Dbx 560A 

Based on the beloved dbx 160A rackmount processor, the 560A is a compact 500 Series compressor capable of dialing in a wide range of compression styles—from subtle to brick wall, and back again. Featuring both over-easy and hard knee compression curves, the 560A is perfect for quickly and subtly compressing vocals without much thought or effort. 

One of its unique features is Infinity+ mode, which utilizes inverse compression to decrease the audio output level below unity gain when an input has gone past the threshold. This essentially allows the 560A to simultaneously act as both a compressor and a gate, making it perfect for both studio and live applications. There are some interesting emulations out there, notably The Commander by Valley People.

Kyle HuntIf you’re interested in purchasing any of the compressors mentioned in this blog, contact a Vintage King Audio Consultant via email or by phone at 866.644.0160.