The AT-1’s crossover network is split over two separate printed circuit boards (PCBs). The high-pass filter section is attached to the rear of the rear terminal plate, in the usual manner, and comprises a three-position switch, a pair of MPT ‘Yellow’ capacitors, a pair of Dayton ‘Audio Grade’ MPT capacitors, seven 10W cermet resistors, and three inductors, two of which are ferrite-cored and sit parallel with each other, and one of which is air-cored and properly cross-mounted on the PCB. The PCB for the low-pass filter section is mounted high up on the inside of the enclosure, and comprises a single iron-cored inductor, two 10W cermet resistors, one MPX capacitor and one MPT ‘Yellow’ capacitor bypassed by a 12µF 100V bipolar electrolytic. According to Atlantic Technology, the topology of the circuit controlling the bass drivers is not a ‘low pass’ filter as such, but is more properly characterised as a ‘tank/trap’ circuit and results in a nominal crossover frequency of 2kHz. Internal wiring is via individual strands of 16AWG cable, soldered to the PCBs but attached to the drivers via spade-lugs.
In Use and Listening Sessions
When I finally got around to firing up Atlantic Technology’s AT-1 speakers, I was as impressed by their sound as I was by their appearance. My immediate impression was of a lively, dynamic loudspeaker system with a flat, well-balanced and nicely extended frequency response and that’s the impression that stayed with me not only throughout my listening sessions, but also after I’d put the speakers away for a few weeks, then re-connected them for a ‘reprise’ audition, to make absolutely certain that my first impressions were accurate.
Despite all Atlantic Technology’s predictions that I’d be most impressed by the bass, I have to confess that what most impressed me about the sound of the AT-1 speakers was the clarity and articulation of the midrange, and the almost holographic sound-stage of the imaging—at least horizontally, the stage depth wasn’t quite at this same extraordinarily high level. There is one caveat to this sound-staging, which is that like all MTM driver arrays, it’s absolutely critical that your ears are on-axis with the tweeters, and that you’re in the far field… so if your listening position is necessarily closer than about two metres, you just won’t get the full effect. I was transfixed by how the AT-1s reproduced ‘Home’, an album released by Emma Gilmartin and Tony Gould. It’s recorded clean and plain, and the songs are unashamedly sentimental, but it’s all good, because with just Emma’s unadorned voice (sometimes a cappella) and Gould’s lone grand, it’s incredibly revealing of a loudspeaker’s deficiencies, and none at all were audible when I used it to audition the AT-1s. (Gilmartin’s voice is these days unusual because she uses almost no vibrato.) The bonus is that if you have small children, they’ll probably love going to sleep to some of the songs on this CD (Rainbow Connection, You Are My Sunshine, Que Sera Sera, Homeward Bound). There’s also a lovely version of Janis Ian’s Jesse in which Emma shows off her insanely accurate ability to perfectly pitch any note, even when it’s a deliberate discord (actually, she demonstrates this right throughout this album, but she sings some of my favourite ‘impossible’ intervals on this track and nails them without so much as a micro-slide onto the note.)