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Field Test: InnerTUBE Audio Dual Atomic Squeeze Box
By Michael Cooper

Nov 1, 2005 12:00 PM

HIGH-END STEREO COMPRESSOR/LIMITERWe've all been here before: You slam a snare drum track with a compressor to put a point on it and then suffer the tedium of gating the resulting pumping hi-hat bleed. An obligatory ritual? Not anymore. The InnerTUBE Audio Dual Atomic Squeeze Box can nuke percussive and other types of tracks while keeping gain-modulation artifacts to virtually zilch.

From its etched front panel and stalwart 2RU chassis to its beefy, positive-action controls and curved VU meter cutouts, the Dual Atomic Squeeze Box oozes quality. A Link switch and duplicate rotary controls for its two channels accommodate either true stereo or dual-channel operation. Continuously variable input and output level attenuators adjust respective gain from maximum down to infinity cut. The squeeze (threshold) and attack time controls are also continuously variable, whereas the release time and slope (ratio) controls are stepped. For each channel, the release time's range can be modified by two three-way switches: mode (marked slow, medium and fast) and hold (a release time multiplier marked 1x, 2x and 3x).

Each channel's VU meter is backlit and has a recessed calibration trim to zero it. A beefy toggle switch for each meter selects either output level or gain-reduction amount to be displayed. Rear panel I/O connections for each channel are via 3-pin XLRs. A 4-pin XLR provides connection to a 56-inch-long cable serving the outboard power supply, which is a weighty affair sporting a power switch and indicator, carrying handle and IEC receptacle (the latter for its detachable AC cable).

TOP SECRET
InnerTUBE Audio declined to divulge what type of gain-control circuitry the Dual Atomic Squeeze Box uses, but the company told me it wasn't a VCA, opto-electronic cell, variable-Mu tube, FET — or anything else ever used before. As there is no owner's manual for the unit, a “cut sheet” and some chats with designer Stayne McLane were my only informational sources about the unit.
Octal dual triodes and nickel-core input and output transformers serve the Dual Atomic Squeeze Box's all-tube audio path. Attack and release times aren't titled with time-based references on the front panel, in part because they are program-sensitive. In fact, all of the rotary controls are titled with arbitrary numbers (1 through 10 or 11). The slope controls effect ratios from 1:1 to roughly 20:1, adjusted in equal steps. The unit can deliver more than 20 dB of compression and handle at least +20dBm input level (conservatively rated).

FUN IN THE STUDIO
I quickly discovered that the Dual Atomic Squeeze Box's release and slope switches have no end stops, which is neat because you can switch back and forth between extreme settings without having to step through intermediate ones. The unit's Slope switch incorporates a wiper with two half-moons; at the crossover between them, the control switches between two high voltages, causing a crackling noise as you switch between the two corresponding slope settings. It's a minor annoyance.

The Dual Atomic Squeeze Box put a heightened point on kick and snare drum tracks, which — when the processed results were combined with the dry source tracks — really made the drums rock. Amazingly, I could hear no pumping of the snare track's hi-hat bleed, even with up to 20 dB of gain reduction!

On quadruple-tracked background vocals, dialing in a very fast attack, very slow release and high slope slammed the tracks with more than 20 dB of gain reduction without thinning their tone — just what this arrangement needed for the background vocals to sit unobtrusively at ear-candy level in the subsequent mix.

Next up was electric guitar, blowing through a cabinet miked with a Royer R-122. Setting very fast attack and release times and sky-high slope for 8 dB of gain reduction on peaks, the sound was dynamite — warm, crunchy and in-your-face, but again, with no hint of pumping.

The unit also lent excellent dynamics control — characteristically not unlike that provided by an opto-compressor — to lead vocals. I heard some loss of depth with 6 dB of gain reduction, but no pumping.

The Dual Atomic Squeeze Box sounded really incredible on stereo room mics for drums. Dialing in 10 dB of gain reduction — using ultra-fast attack and release times and a high slope setting — produced absolutely slammin' tracks. But what amazed me was that there was only very mild pumping on crash cymbal hits. The unit's Link switch kept the stereo image rock-solid.

I found the unit's lowest slope setting above 1:1 to be too drastic for most 2-bus applications. Also, the review unit had no bypass switches, making A/B comparisons difficult without using a console equipped with insert switches. (InnerTUBE Audio says the next production run will include channel bypass switches.) Just for grins, I dialed in 20 dB of gain reduction on a broadband percussive mix to see if I could make it pump. Not a chance. I was dumbfounded.

NUCLEAR WINNER
The Dual Atomic Squeeze Box is unequaled for stereo applications in which transparent yet heavy compression may be desired, such as on room mics for drums. It also does a stellar job on a variety of mono tracks. At $6,750, it's not inexpensive, but it does what no other compressor I've ever heard can do.
InnerTUBE Audio, 805/688-8286, www.innertubeaudio.com.
Mix contributing editor Michael Cooper is the owner of Michael Cooper Recording, located in beautiful Sisters, Ore.