ATC monitors are popular in professional circles because of their sheer accuracy and quality, but by the same token, they aren't cheap. However, ATC have collaborated with Wilmslow Audio to produce kits based on their popular SCM 50 and 100 monitors that are easy to build, offer high performance, and are very attractively priced compared with their commercially available counterparts. The kit includes bass and mid‑range drivers supplied by ATC as matched pairs, plus Vifa tweeters which are tested at the Vifa factory to ATC's own test specifications. ATC designed the new passive crossovers, though for those users requiring an active system, the ATC Mk1 tri‑amp/crossover packs are available as options.
The cabinet design is based on heavy (25mm) MDF panels which are accurately machined for easy assembly, requiring only PVA wood glue. Indeed, the most technical part of the whole operation is soldering the (included) speaker cable between the drivers and ready‑built crossover board. The cabinet is designed to be used either floor‑standing or on a low stand and is taller and thinner than the commercial SCM 100. As far as I can see, the only real difference between the kits and the SCM 100 is that the kit version uses a standard rather than Super mid dome (making the available SPL very slightly lower), and that the passive crossover is specially designed to go with the kit. Because the cabinets are designed for use with either passive crossovers or Amp Packs, they have a recess in the rear panel which accepts the Amp Pack. If this isn't required, the passive crossover (which resembles a small sub‑station) is mounted inside the cavity.
I found the kit simple to assemble, largely because the parts are so accurately machined, but veneering is less easy, so painting is recommended for those seeking an easy life.
Sonically, the speakers are exceptional, though you do need at least 250 watts of quality amplification per cabinet to take advantage of their dynamic range. For those unfamiliar with ATC monitors, they are incredibly revealing, ruthlessly accurate and very, very smooth. The soft‑dome mid and high frequency drivers provide a very even dispersion which helps cope in reflective rooms, and the overkill magnetic assemblies pay off in allowing the speakers to express a wide dynamic range without suffering significant power compression. In subjective terms, the difference in performance between the SCMK 100s and the ready‑built SCM 100s is minimal, and anyone who's not afraid to get their hands dirty for a few hours should look very seriously at these kits. For the smaller studio, the SCMK 50s are perhaps a better proposition, as they're a little smaller and can be driven with slightly less amplifier power.