M-Audio DSM1 Monitor Speaker

Although they look like conventional two‑way active nearfield monitors, the DSM1s actually feature selectable analogue or digital inputs, and use on‑board digital signal processing rather than analogue circuitry to provide crossover, EQ and level trim functions, just like the EX66s.

Using DSP allows more switchable options to be included without having to increase the number of components (especially when it comes to EQ and filtering) and it also makes it possible to build in subtle EQ curves to counter anomalies in the driver and cabinet responses. Some speaker designers, though, are philosophically opposed to trying to 'EQ away' problems, as they feel it introduces other equally unwelcome side-effects, often relating to phase.

As you'd expect, the HF and LF drivers are independently driven by two separate power amplifiers (LF 100W, HF 80W) but they're based on the Class-D technology that's more often associated with high‑efficiency, large‑scale PA amplifiers. The woofer's 6.5‑inch black anodised aluminium cone is a seamless, concave dome, suspended in a roll‑surround fixed to a steel frame. The tweeter comprises a one‑inch, soft‑dome, soft fabric Teteron driver with a Neodymium magnet and built‑in heat sink, and operates up to 27kHz.

The analogue inputs are presented as balanced XLR or quarter‑inch TRS jack connectors, and these are summed, so that both can be connected, and even fed, at the same time. Because the crossover is based on a DSP, the analogue signal is internally converted to digital data for processing. The digital inputs (AES-EBU and S/PDIF connectors, with a further S/PDIF Thru for linking) automatically slave to the sample rate of the input and can operate at up to 192kHz/24‑bit. Unlike the analogue inputs, only one digital input can be fed at a time.

The enclosure is a simple black‑painted, rear‑ported box, but its reinforced MDF structure makes it very rigid, and the corners are nicely rounded to reduce diffraction and to improve the cosmetics. Waveguides are moulded into the driver surrounds to control dispersion, and there's a blue LED to let you know the speakers are powered up. Other than that, the front panel is very streamlined and simple — which is more than can be said of the busy rear panel, where all the connectors and switch options reside. The cabinet size is a compact 12.8 x 9 x 10.3 inches (325.5 x 228.7 x 261.5mm), and the weight per speaker is 16.5lbs (7.5 kg).

Internally, the signal path uses a 36‑bit digital signal processor, which, in addition to hosting the fourth-order crossover, includes six 'Placement Setting' filters to compensate for the speaker's position, either within the room or relative to the surface of a desk or console. A volume trim control adjusts the level of the input signal in the digital domain over the range ‑22dB to +10dB, and the analogue input can be set to a sensitivity of +4dBu or ‑10dBV. Where the digital input is used, one speaker links to the next using a coaxial cable, and a switch on the back of each speaker determines whether it receives the left or right channel signal.

All this adds up to a compact monitor that's capable of covering the frequency range 42Hz-27kHz, with a maximum SPL of 110dB at one metre. The crossover operates at 2.7kHz with a steep 24dB/octave filter slope, and the overall response of the speakers can be adjusted in the digital domain using 12 DIP slide-switches on the rear panel, the settings for which are clearly silk‑screened to save you hunting for the manual. The HF shelf can be set to +1.5, ‑1.5 or ‑3.0 dB, the mid EQ to +1.5, ‑1.5 or ‑3.0dB, and the high‑pass filter to 40, 60, 80 or 100Hz, with a 12dB/octave slope. There are two further 'Desktop' EQ settings, intended to compensate for reflections from the console surface, offering a cut of 1 or 2dB at 220 or 175Hz.

This is the first time that I've tried a monitor with built‑in equalisation dedicated to tackling desk reflections, but it's well known that early reflections from a mixer or other flat surface can introduce humps into the lower mid-range, so having the opportunity to smooth them out to some extent is very welcome. The correct setting has to be chosen by ear because there's no reliable way to predict at what frequency the problem will occur, or how much cut will be needed to neutralise it. In any event, the nature of desk reflections is that comb filtering results from the combined direct and reflected sound, so there may be dips as well as bumps to iron out. Compensating for the worst of the bumps is about the best you can hope to achieve with a system like this one, but it can bring about a worthwhile improvement in lower‑mid clarity.

The published spec quotes a signal‑to‑noise ratio for the electronics of 102dB A‑weighted, for a sample rate of 96kHz with the analogue input in use.