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Studio Review: Coleman Audio RED48 Analog Summing Device/Monitoring Controller by Rob Tavaglione

Glenn “Coley” Coleman builds simply designed products, always using highquality components.

Glenn “Coley” Coleman builds simply designed products, always using highquality components. His products solve problems without frailty, flashy frills or corporate hyperbole. Upon hearing of the unique feature set of RED48, I was intrigued, as Coleman quality in such a forward-thinking design could make for a potent piece of gear.


The RED48 is really a three-function unit: a transformerless analog summing device, a communications/cue system and a “center section of a console” (with passive electronics, stepped level control), all in a 2U chassis. Three stereo input sources on XLRs (or the summed mix) are selectable for monitoring. There’s also a stereo “cue” input (dual quarter-inch TRS) that can be routed to the control room/engineer phones output (front panel quarter-inch TRS) or via “cue” output to talent/performer (with dual TRS to a headphone amp or similar). A small talkback mic is included, connecting via eighth-inch mini-plug, and is engaged with a momentary switch.

Summing is accessed with six DB-25 connector inputs; with 48 tracks of analog summing arranged in stereo pairs only, there are no pan controls, mono switches or faders, and all inputs are summed to L/R at unity gain. Mix output is via two XLRs to the user’s master deck or back into the DAW. Insert points (stereo send and return) are provided for the mix via four TRS jacks.

RED48 also includes a single, wired master L/R fader (a Penny & Giles long throw) in a remote desktop box that is very useful (as the only other level controls you’d be using would be ITB). This remote also wisely houses backlit dim, talkback engage and slate buttons.

In Use

Setup was easy and I was running in no time, other than stumbling upon mismatched threads between my cabling’s DB-25 connectors and the RED48‘s connectors. Did you know there are metric and SAE thread types used for DB25s? Ugh—it’s like pin 2 hot vs pin 3 hot all over again (though SAE 4-40 is specified in AES standards— Ed.). Anyway, once connected, I took an ITB mix session and spread it out over 24 channels (12 stereo pairs) of output via D/A converters and then into the RED48. Bam! Instant OTB (out of the box) mix.

Immediately, mix differences were present to my oversensitive ears. First, the RED48 has back and bottom: deep bass extension yet a lack of bass “color” with no frequency-based humps, dips or other negative interpretations. Second, I noticed a lack of harshness, as the tracks lost the forwardness that I’ve heard via other summing methods—either ITB or in my Soundcraft Ghost analog console. Third, and perhaps most importantly, the soundstage took on an entirely different shape and size. Admittedly, my ITB mix was every bit as wide, with even more precise panning, and the RED48 mix had a sense of front/back and depth that was obviously pronounced. In particular, reverbs took on more space and realism, with increased audibility as well as presence.

I certainly missed insert points, as I wished to process individual tracks as well as apply a little NY-style parallel processing to my groups as well. This function is achievable by routing DAW converter outputs to dynamics processors before hitting the RED48; 48 channels is enough room to accomplish a 32-channel mix with eight more channels of subgroup for NY-ing. Nonetheless, I didn’t have a patchbay or cabling flexible enough to accomplish all my insert point needs, and summing units with channel inserts are rather expensive.

As I mixed, I found myself wishing for numerous analog desk conveniences, which I have on my console: a mono summing switch for checking polarity, channel faders to give me a little more past unity at crescendos, aux sends to hit my outboard effects and level meters! Other than the total absence of metering and the lack of a mono switch (pretty important needs, IMO) the other conveniences can be worked around. These “no console” sacrifices are largely overshadowed in importance by a little thing known as “total recall,” as one can perfectly recreate a mix just like you would ITB with the exception of needing to chart any L/R insert processor settings (or others, if you patched processors inline).

To My Ears

The RED48 is quiet. Those passive electronics don’t hiss or hum, even when cranked, so you may forget you are “up full”—a good thing for the backlit fader remote buttons or you wouldn’t even know RED48 was powered up.

The RED48 barely has a sound: no color, no attitude, very dynamic and plenty quick, though the extended bass might be mistakened for bass hype. About a third of my clients preferred ITB mixes while the other two-thirds preferred the RED48.

The RED48’s headphone amp sounds great, and all its switches feel great—quality components.

The RED48 overloads gently (with a grainy fizz) if hit with too much level—no nasty “clacks,” like some analog.

The RED48 is simple, sturdy and proper; I’d expect a lifetime of service, if treated right.

If you place importance on nebulous qualities like mix depth, imaging, a sense of space and low-level-detail, go get a Coleman RED48. They’re only $2,500 and it’s a wise investment for your work. If you like analog summing, but require a tonal shift and some color to get your bus moving, then the RED48 is not your choice. Others manufacturers in this market category offer character via transformers (Phoenix, SPL, Thermionic Culture); many have them on the L/R, and a few have them at all inputs. If you need insert points, those are available, too, but only on a couple of units that have price tags over $3,500. Many high-end analog summers offer pan pots, faders, level boosts and some even auxes—but then that’s basically a mixer, isn’t it? Part of our goal here is total recall and decades of durability, and, in general, fewer parts = fewer problems.

For what it does, at this price, with this many channels, the Coleman RED48 is the best deal in analog summing today.