The editor-in chief's extensive preamble on the Ultrumax M1-ST pointed out both lofty aspirations and potential pitfalls. If you waited for the continuation, let's get started. Any discussion of the M1-ST brings us immediately to the star of the show, Mark & Daniel's new top-line DM-9a AMT. To put it bluntly, it's a groundbreaking achievement in bandwidth for an air-motion transformer. It marks the first time this technology can be heard and judged not merely as a tweeter but legitimate widebander. The potential of such a device is staggering. Does the Ultrumax M1- ST live up to that potential? Let's take a closer look.
The Ultrumax M1-ST is really quite petite. It's reminiscent of the Maximus Mini Monitor though slightly taller to incorporate the top-mounted omni AMT super tweeter. It's less deep since the cabinet needs no woofer volume. What appears to be a bottom port is actually a cylindrical recess to accommodate mounting hardware for the optional stereo bass modules. Lest you think that small means light, lifting these little lovelies quickly dismisses the notion. The M1-ST enclosure in the firm's synthetic marble weighs in at 8kg/17.6 lbs each. No painted MDF here. The aesthetic is posh angular with high-end refinement. The review sample featured the Phantom White finish. It replaces the former solid white as the new standard color. It better emphasizes the polished marble aspect to differentiate it from the gloss white lacquer crowd. Starry Black is the other standard color, with custom options available. While fit 'n' finish of the CAM cabinets was first rate, my samples showed signs of being rushed out for review. The paint finish on the driver mount plates and workmanship on the back panel looked somewhat unpolished and not commensurate with the elevated ambitions or price. Since the firm's quality control standards are normally high, I'll assume that what I received were rushed samples not representative of final production. Mr. Daniel Lee in fact confirmed that the QC slip was caused by scheduling conflicts with the Bejing hifi show. He assured me that formal production runs must meet their traditionally rigorous standards.
Let's examine the basic components. The DM-9a driver has an average efficiency of 86dB and impedance of 2.8Ω. Applied in the Ultrumax M1-ST, that impedance improves to 3-6Ω but efficiency drops to 84dB. Those numbers dictate an amplifier with serious horsepower comfortable with a sub 4Ω load. The AMT super tweeter extends to 32kHz and increases the sense of soundstage space. A rear-mounted pot adjusts its levels to room condition and taste. Today's M1-ST is a widebander but not full bandwidth so an internal high pass cuts in at 190 cycles to allow it to mate with various subwoofers including those without their own high-pass management.
To prove that the M1-ST could operate with a non-Mark & Daniel bass solution, my SVS SB3000 sub did the honors in a 2.1 config. Aside from manageable size, responsiveness and true subsonic reach, the SB3000 is fully app controllable from phone or tablet. That makes adjustments possible in real time. With my trusty Audio Tools app providing measurements to corroborate my ears, selection of crossover frequency, slopes, timing and equalization were rapidly assessed and stored in presets to accommodate different setups and cabling. Since about the single sub/high filter approach Srajan expressed theoretical and practical misgivings all of which I share, my unenviable job was to try and prove us both wrong. Daniel Lee was confident that there'd be no issue. Could I make it work?
