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Aphex Systems 240 Dual-Channel Gated Compressor

Hardware audio processors struggle to find relevance in the increasingly virtual studio world, but dynamics processors such as Aphex Systems' Model 240 enjoy a strong demand from the live production and broadcast markets

Hardware audio processors struggle to find relevance in the increasingly virtual studio world, but dynamics processors such as Aphex Systems’ Model 240 enjoy a strong demand from the live production and broadcast markets. Competition among manufacturers remains stiff within these markets, however.

Aphex Systems has traditionally aimed to differentiate its products from the old industry standbys and inexpensive imports through its sound quality, reliability and innovative features. This review sees whether the Aphex Systems Model 240 gated compressor ($599) meets these goals.


FAST FACTSApplications

Studio, broadcast, live

Key Features

Dual-channel gate and compressor; XLR and 1/4-insert I/O; flexible balanced or unbalanced operation; patented Logic-Assisted gate and Easyrider compressor technology; external key insert




Aphex Systems
The Model 240 is a single-space rackmount analog dynamics processor featuring two channels of compression and gating. The two channels can be operated independently or linked for stereo program use. The 240 combines Aphex’s patented and award-winning Logic-Assisted Gate and Easyrider Compressor technology, and links them together in a unique, interdependent relationship (more on this later).

Each channel has XLR and TRS 1/4-inch inputs (in parallel) and outputs (independent, impedance balanced). All input connectors can be fed balanced or unbalanced signals; the impedance-balanced XLR outputs can feed balanced or unbalanced destinations, while the 1/4-inch outputs are for unbalanced use only.

The operating level for each channel is selectable between +4 dBu and –10 dBv via rear panel switches. Also on the rear panel are two 1/4-inch key insert points (TRS send/return configuration) for adding an equalizer before the threshold detector circuit or inputting an external key source

Each channel consists of a Logic-Assisted Gate section followed by an Easyrider Compressor section. Gate controls include threshold (-60 dB – 20 dB), attack (4 uS – 100 mS), hold (5 mS – 500 mS), release (100 mS – 1 S) and depth (2 dB – 80 dB). The fixed-threshold, program-adaptive Easyrider compressor section features a 3:1 ratio with a medium – hard knee. Its simplified set of controls includes Drive (compressor section input gain), Speed (basal time constant adjust; effectively, release time) and Output level.

Other front panel features include power, stereo link and processing bypass (per channel) buttons. A unique metering scheme simultaneously displays a channel’s gate gain-reduction status (downward-moving dot) and compressor gain-reduction status (downward-moving red bar) on a single 10-segment LED meter.

In Use

My first encounter with Aphex products was, like many engineers of a certain vintage, the ubiquitous Aural Exciter. The company and the novel product became fused to many (say it with me now: “aphexauralexciter”). As the company expanded into high-quality, innovative dynamics processors and preamps, a lingering association with the original Aural Exciter may have led to the belief that the company was a one-trick pony.

That erroneous perception is hopefully long in the company’s past. Like the several Bryston power amps I have owned and brutalized for 20-plus years (and worship for their stalwart performance), I have the utmost respect for Aphex products. The Compellor became one of my all-time favorite pieces of gear at my commercial facility; all of the Compellors (and the excellent 612 and 622 gates) continue to function flawlessly, despite constant use for more than 15 years.

The Aphex 240 continues the Aphex track record with a confidence-inspiring build quality and, as I have found with all Aphex pro-level products, an impeccably clean signal path. Logical control placement and some of the best front-panel labeling I have ever seen made learning and operating the 240 a quick and intuitive affair. In high-pressure situations, these are essential qualities – qualities that were sorely lacking on a competitor’s product I recently used at a broadcast facility. It’s always gratifying to experience something done right immediately after toiling with something just the opposite.

Most compressor/gate combo units I have used invariably give the short shrift to one processor or the other (and sometimes both). Although there are a few obvious controls that would have been included on a single-purpose processor, Aphex pulls off the dual-channel compressor/gate trick far more seamlessly and with greater flexibility than any other similarly equipped unit I have used.

This success is due in part to Aphex Systems’ established Logic-Assisted Gate and program-adaptive Easyrider Compressor technology, and in part to the unique manner in which the two processors are linked. Instead of two processors ignorant of the other’s existence, Aphex has joined its processors in a cooperative gate/compressor marriage (legal in most states), avoiding the common and wholly unwanted situation where the gate is closing (reducing the signal level) at the same time that the compressor is releasing (increasing the level). Aphex achieves cooperation between the processors by intelligently “freezing” the compressor’s operation whenever the gate is closing or closed. The 240 gate/compressor combo performed better in this respect than my usual path of two single-function processors in series.

If you haven’t used an Aphex product equipped with a Logic-Assisted gate, you will be impressed with both its ease of operation (especially in setting a proper threshold) and flexibility. In a nutshell, the Logic-Assisted gate ensures that once the threshold is reached, it triggers the full attack-hold-release cycle. This has the ultimate effect of consistent gating performance without incidents of chatter, late or early closings and other misfirings.

Compared to typical gate/compressor combos, the 240’s gate section provides a generous set of controls, including an all-important depth control. This makes the 240 suitable for anything from full-on gating to subtle downward expansion for reducing unwanted ambience and/or noise (perfect for TV studios and less-than-perfect locations).

I would be remiss if I didn’t lament the omission of a built-in key filter control, for which I would gladly sacrifice the key insert point. Of course, then someone else will complain there’s no external key insert…

The compressor section of the Model 240 seems woefully lacking at first glance, considering that it consists of just three controls, two of which are input and output gain. But I found to my surprise the compressor section quite effective for most applications. Between the program-adaptive Easyrider technology and the unified Speed knob, it was extremely easy to dial up appropriate settings and tweaks. Its fixed 3:1 ratio combined with a reasonably hard knee proved to be a good design choice for covering the greatest range of uses. It should be noted, especially for on-air use, that the fixed threshold nature of the compressor requires a bit more care (and two hands) to increase or decrease gain reduction without noticeably affecting output volume.


Aphex Systems has made some of the finest products I have used in studio and broadcast applications. The Aphex 1100 is second only to APIs as my first-call high-end mic preamps, and I have yet to find any products that rival the transparent leveling of the Aphex Compellor or flexibility of the 622 gate. The Aphex Systems Model 240 inherits many of its predecessors’ traits and technologies and links them together in an effective package that’s sure to impress demanding broadcast, live and studio engineers.

PAR Studio Editor Stephen Murphy has over 20 years production and engineering experience, including Grammy-winning and Gold/Platinum credits. His website is