The Marc One from SPL is a monitor controller and 32-Bit AD/DA in SPL's One series of high-quality audio equipment. This unit offers two stereo inputs (one balanced, one unbalanced) as well as two speaker outputs, a headphone output, and a subwoofer output. As with the inputs, the output sections give you a choice of balanced or unbalanced 1/4" connection points. You'll also note the USB port, through which you can record or playback 32-bit audio at high sample rates.

Indeed, the Marc One can support PCM sample rates up to 768 kHz. If you have DSD audio you'd like to hear, you can play it via DSD over PCM (DoP) up to DSD256. Because this unit has line inputs as well as outputs, you can even record audio at these high sample rates and resolutions, which is great for capturing vinyl records or recording instruments such as analog synths. On its front panel, you'll find an input selector that lets you switch between your two line sources, which you can also blend, if that is your desire. An output selector allows you to choose between your A and B output sets. Another front-panel switch sums the stereo output to mono, which can be useful for checking the integrity of your mix. You can also swap the left and right channels in order to ensure that you're center elements are truly centered.

In the headphone section, note the Crossfeed knob. This engages the Phonitor Matrix, SPL's technology for emulating speaker positioning, within a room, all in your headphones. With the Crossfeed knob, you can dial in subtle amounts of the opposing channel to emulate the feeling of speakers. Mixing engineers might find this feature particularly handy when mixing in headphones.

The headphone amp itself utilizes a Class AB design, and is able to power both high- and low-impedance headphones alike. You can go between your favorite consumer-grade closed-backs and your high-grade open backs without problem. A 12V external power supply unit is included.