Review: SPL Crimson

Providing the flexibility of a high-quality, adaptable USB audio interface and a stand-alone monitoring box, SPL's Crimson makes elaborate routing needs easy to achieve as Joe Albano discovers.  

Crimson is SPL's new swiss-army-knife USB Interface/Monitoring Station, combining a 6x6 interface (4x4 analog) with a full-featured monitoring station. But that simple description doesn't really capture the clever design of the Crimson! It seems that SPL set out to provide a box that would seamlessly handle all of the interfacing and monitoring tasks that the typical DAW operator would require with a few simple button pushes, and without the need for an elaborate setup. Besides basic interfacing and monitor level control, Crimson offers a full feature set including A/B options, a separate musicians' headphone mix with talkback, and an alternate operating mode (Artist Mode) that internally reconfigures the unit for tracking or mixing needs. Crimson can be used either as a full-featured USB interface, or independently, as a stand-alone monitoring station.

The SPL Crimson (Front).

The SPL Crimson (Front).

So how did SPL go about packing a lot of flexibility into such a simple, user-friendly package? Let's take a closer look..

Gozintas & Gozoutas

The SPL Crimson (Back).

The SPL Crimson (Back).

Crimson is a class-compliant USB 2 DAW interface—that means no software driver is required when hooking it up to a Mac. It's a 6x6 interface—4x4 analog ins & outs, plus 2 additional channels of digital I/O via S/PDIF. The analog ins include 4 line inputs on balanced TRS jacks. There are 2 XLR mic inputs, with discrete mic preamps (with 60 dB of gain), 48v Phantom Power, and a gentle HPF (6 dB/oct @ 75 Hz). There are also two front-panel instrument-level inputs, with their own gain knobs, for electric guitar, bass, or other low-level sources.

But note that while I've described 8 inputs, only 4 can be used simultaneously. When cables are plugged into Line 1 and 2, they override Mic 1 and 2. And when instrument cables are plugged into the two instrument inputs, they override Line 3 and 4. The S/PDIF I/O allows you to add two additional recording channels, or connect a CD/DVD/external player as a convenient way to A/B your work against commercial mixes/masters. 

As part of its dual-functionality as an interface and monitoring station, Crimson also provides 3 other stereo “Source” inputs: a pair of balanced TRS jacks (for pro-level devices), a pair of unbalanced RCA inputs (with appropriate gain, for consumer-level gear), and a stereo 1/8th-inch connection (for portable players). The TRS input doubles as a connection for a talkback mic—more on that later.

There a 4 analog outputs, configured as stereo pairs, labelled Speaker A and Speaker B. Speaker A are balanced XLRs; Speaker B are balanced TRS jacks. If these are hooked up to two different pairs of powered speakers, as the labeling would suggest, Speaker B offers screw-pot trims to match the level with Speaker A, a nice touch. However, as line-level connections, these outputs don't necessarily have to be connected to speakers. Speaker B, in particular, can be treated as exactly what it is—a second pair of DAW outputs—and used for another purpose. Recommended applications include using it as a source for an independent musicians' mix, connected to a multi-headphone amp/distribution box, or as mono or stereo insert sends to external analog signal processing.

Crimson has two built-in headphone jacks, with independent level controls. They can be fed from the same source (the main mix), or from separate sources—Phones 2 can carry a dedicated musician's submix, when Artist Mode is enabled.

Finally, Crimson thoughtfully provides MIDI in and out on traditional DIN connections, to cover all the I/O bases a small DAW rig would be likely to need.

Artist Mode

The front panel is straightforward. There are knobs for mic and instrument input level, separate level controls for the two headphone jacks, and buttons for enabling monitoring of the various inputs and outputs.  But it's the button labelled “Artist Mode” that gives Crimson its extra utility and convenience. With Artist Mode enabled, Crimson's 2 stereo pairs of outputs are functionally separated. The main outputs, DAW 1/2, carrying what would be the Control Room mix in a studio, are routed to Speaker A and Phones 1. The DAW 3/4 outputs are routed to Speaker B and Phones 2. This allows for several different applications—the most obvious use is as an independent musicians' headphone mix, tailored to the needs of the performers being recorded. A separate musicians' mix, from the DAW's 3/4 outputs, can be sent through Crimson's Speaker B outs to a headphone amp in the live room, or through Phones 2, in a one-room studio. The “A to B” button quickly routes the main mix to the musicians' headphone feeds, avoiding re-patching in-between takes.

With Artist Mode enabled, the Left Source 1 input can be used with a talkback mic (it's still a line-level input, so you will need an external mic pre). Engaging the Source 1 “Jack” button routes that mic/talkback signal, panned Center, to Speaker B and Phones 2 (the musicians' headphone feeds). Just as with a console talkback feature, the signal in Speaker A (Control Room) is dimmed when using talkback, so the talkback mic won't pick it up and blast it into the musicians' feeds. Most interfaces and many monitoring stations don't offer talkback functionality, and it's a very welcome addition here!

SPL Application diagram: “Recording Multiple Artists with talkback”.

SPL Application diagram: “Recording Multiple Artists with talkback”.

Besides being utilized for dedicated musicians' mixes, the independent monitoring path of Speaker B in Artist Mode also allows those outputs to be pressed into service, with only a little re-patching, for inserting up to two channels of outboard analog processing. SPL offers up a few diagrams showing suggested uses for this routing flexibility (see below).

Various Crimson application diagrams.

Various Crimson application diagrams.


Now, experienced engineers and recordists may say, “but I can do all that routing and monitoring stuff with any interface, headphone amp, cables, patchbay, etc.” Of course, they'd be right—I have those functions set up in the studio, and even in my small home rig, as well. But what's cool about the Crimson is that it not only incorporates all of this in the box itself, without the need for a lot of external patching and ancillary utilities, but that it makes this functionality available to DAW users who may not be comfortable rigging it up themselves. The full PDF manual includes many helpful application notes to help less-experienced users get the most out of its features. 

At $699 (or a little less, street), Crimson packs two high-quality products into one—a USB interface and a full-featured Monitoring Station—and this allows for a level of convenience and utility that makes the whole more than just the sum of its parts. For the small studio operator or home recordist, Crimson would make a great centerpiece to any DAW-based rig.

Price: $699

Pros: Elegant & flexible integration of Interface and Monitoring Station functionality

Cons: Not as many channels of I/O as some similarly-priced units


Joe is a musician, engineer, and producer in NYC. Over the years, as a small studio operator and freelance engineer, he's made recordings of all types from music & album production to v/o & post. He's also taught all aspects of recording and music technology at several NY audio schools, and has been writing articles for Recording magaz... Read More


Nice review Joe! I've been looking for a new interface ... this might be just the ticket.

Want to join the discussion?

Create an account or login to get started!