Critical to almost every aspect of the recording and mixing process is the compressor. They are the gatekeepers of dynamics and the gods of punch and presence. In his latest interview, Alan Parsons mentions three of the all-time greatest compressors: the Teletronix LA2A, the Fairchild 660, and the Urei 1176. Let’s dive a little bit deeper into the similarities, differences, and personalities of these heavyweight compressors.
Up first, the LA2A. Its fame rests in its smooth and clean tone. It can handle significant gain reduction without audible side effects. It is characteristically low-distortion and has a soft knee due to its electro-optical design. While other compressors incorporate solid-state circuitry, the LA2A’s electro-optical gain reduction element means it’s slower, and non-linear when compared to other compressors like the DBX 160 or the Urei 1176. The combination of electro-optical compression, transformers, and valve (tube) amplification allows the LA2A to function as a smooth and musical compressor on vocals. When driven hard, it adds a pleasing saturation distortion, or “dirt” to the sound. Overdriving the LA2A lights up the last tube stage of the compressor, which produces a signature sound that adds bite and helps your vocal sit perfectly into a rock mix.
The most expensive and elusive compressor is the Fairchild 670. It is rare to find this legend in a recording studio, no matter the caliber. Capitol Records has one on its list of outboard gear, and vintage units can sell for around $40,000. This compressor, unlike the slower optical LA2A, has sub-millisecond onset times, which translates to faster responses and more accurate gain reduction. Similar to the LA2A is its soft-knee compression curve, due to tube-based ‘vari-mu’ gain control.
There are many different options for compressors across all levels of the market, so what makes the Fairchild so expensive and, on the whole, revered? The answer lies in its 20 tubes and 14 transformers. The Fairchild brings its own legendary tone, and many engineers like Geoff Emerick (The Beatles) would use it on vocals simply for coloration, with no compression at all. If you don’t have $40K in loose change lying around, Jack Joseph Puig’s “PuigChild” plug-in is an excellent emulation.
Finally, let’s take a look at Urei’s 1176 compressor. It shares a similarity to the Fairchild in that it is not an optical compressor and has faster response times like the 670, but this is where the similarities end. It is a FET-based design, which brightens the tone and adds edge and energy rather than the smoothness and warmth of the 670.
In terms of practical use, the LA2A is often used on vocals for its smooth characteristics. The fact that it is a slower compressor means it follows the vocal line. In a way, this is somewhat more musical in that it doesn’t make its presence known whenever it is working. The LA2A works in conjunction with the singer’s own dynamic changes and phrases. However, because the LA2A is slow, if you are hitting it hard, say on lead vocals, you will hear an initial hit or attack of the singer before the compressor starts working. The solution for this is the addition of another player in the battle for top three compressors: the 1176. Some engineers place these two compressors in the vocal chain to work together. The LA2A, when placed first in the chain before the 1176 will ride the vocal lines with its characteristic smoothness, while the 1176 will reduce those initial hits or attacks missed by the LA2A. The order in which the compressors are placed in the chain is a matter of debate, as this method can work either way. Also, due to their fast response, solid state and FET based compressors like the 1176 and Fairchild are often used on drums.
Finally, the 1176 is also one of the most used compressors on bass, as its coloration of brightness and edge allows the bass to cut through the mix. Using the actual hardware unit general yields better results because, particularly at greater gain reduction levels, plugins will sound more “squashed” and less natural. There is something about the physical act of going through the transformers and circuitry of the physical units that retains a natural feel that warrants getting in the studio and giving these legends a try.