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B Y PA U L V N U K J R .

A-Designs HM2 Compressor “The Nail”
A new approach to dynamics control yields amazing results
A-Designs is a California-based audio company run by Peter Montessi, whose gear has been featured many times in these pages. Most recently, our January 2009 issue featured a review of a 3-band equalizer called the Hammer. The Hammer was designed primarily as a 2-bus or program eq with which to sweeten and caress your mixes, and our reviewer Justin Peacock was pretty stoked, to say the least. I am now equally stoked to introduce its companion piece, The HM2 Compressor, better known to its friends as The Nail. The Nail In build and design the Nail follows in the Hammer’s footsteps as a 2-space, 19" rack device. It is housed in a black brushed aluminum enclosure with large custommilled aluminum knobs, silky smooth pots, and high-quality toggle switches. Adding a bit of blink and bling are a customdesigned 18-stage LED meter and a large guitar-amp-style red jewel power light. Like the Hammer, the Nail is both a solid-state and a tube piece, but not in an either/or way. Instead it is a hybrid design, as stated on A-Design’s website: “The Nail is a Feedback, Diode based design combined with tubes.” You cannot bypass or turn off the tube section, nor can you drive the tube as a separate stage in the chain, as on the Chameleon Labs 7802 (October 2009) or the Summit Everest (September 2010), but that’s not the point here. The Nail offers a fully integrated design that gives you the clean accuracy of solid state as well as the subtle character of tubes, at the same time. Functions and layout The Nail is a dual-mono/stereo device. Each channel’s controls are identically
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laid out on both sides of the unit, with the metering section in the middle, and each section contains matching balanced XLR inputs and outputs on the back. Each channel has fully variable controls for Threshold, Hard Threshold, Attack, Release, Gain (Make-up), Filter, and Mix as well as a set of switches for bypass, meter function and stereo linking. When the unit is in stereo-linked mode, not only are both channels’ thresholds linked, as is common on stereo units, but all of the unit’s controls with the exception of Gain and Mix are controlled entirely by the left side of the unit, making this much more convenient to adjust for stereo use. While many of the features like Gain, Attack, and Release are all standard compressor fare, to understand what makes the Nail stand out from much of the competition we need to look more closely at its other features, starting with its dual Threshold controls. Standard and Hard Threshold (with Filter) The first Threshold knob is similar to that of most compressors. As it is lowered over the input signal the Nail clamps down and evens out incoming transients, and it does so in a very smooth, almost vintage LA-2A-esque way. The Hard Threshold function is where it gets interesting; it’s a setting that only allows the compressor to clamp down as it is crossed. By way of illustration, say you have the Threshold set to –12 dB and the Hard Threshold to –6 dB. The input signal must rise above –6 dB for the Nail to go to work, but when it kicks in, the signal is hit with the amount of compression you’d hear for a signal of –6 dB level, on a compressor with a –12 dB threshold setting. In practice this allows you to have significant compression set up, that only kicks in on

extreme transients, and, well, nails them back down. (Sorry.) In a sense, this lets the Nail act as a very musical limiter. Where most compressors have a single sidechain frequency or perhaps a few preset choices (if they offer sidechaining at all), the Nail lets you vary your sidechain frequency from 8 Hz all the way up to 250 Hz. Frequencies below the set level will be compressed if higher-frequency content triggers the Nail, but they will not themselves cause compression to kick in. This feature works hand in hand with the Hard Threshold mentioned above, and really allows you to smooth out higher transient frequencies in a mix without the extreme pumping that can be caused by an aggressive kick drum or bass. Mix, meters, and more The Nail’s Mix is a feature that has been sneaking into compressor designs for the past few years; it allows for in-the-box parallel compression, where the dry signal can be blended with a compressed signal for a fuller and yet natural sound. It is very popular on the drum and master bus. Unlike most compressors that favor visually sexy but less responsive VU meters, the Nail uses the above-mentioned 18 stage dual LED. When switched to its gain setting it gives level and clipping information, while in gain reduction mode it changes to a hard red bar in the center and shows gain reduction below that. The Nail has no Ratio control; it offers a variable ratio that self-adjusts based on the Threshold. With no published Attack and Release specs, all you need to know is that this unit can be obscenely fast or ultra slow, all while remaining clean and smooth.

Recording - October 2011

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