Although ATC (Acoustic Transducer Company - based in a picturesque location in rural Gloucestershire) enjoys strong brand recognition in the professional domain of recording studios, the brand is largely unknown to users of domestic home cinema and multichannel audio.
So for those who don't know, a measure of ATC's serious multichannel intent can be gleaned from the fact that the company produces no less than six separate multichannel Concept Collections, ATC speak for speaker packages, four of which are fully active (ie self-powered).
The Active Concept 5, reviewed here, is the penultimate ATC package, at a decidedly serious £11k all in, though buyers should remember that there may be system savings in eliminating a costly multichannel amplifier in favour of a processor/preamp.
Like other ATC systems, however, each of the speaker models is available piecemeal, and with discretion (ie avoiding wild size mismatches etc) can be mixed and matched with any of the other Concept speakers, all of which are designed with common voicing and dispersion in mind. Note also that the system is available to order rather than from stock: your dealer will advise on delivery timetables, and any customisation required to match specific listening room or system requirements.
As I indicated, this is a very serious system. The four Active 20 satellites are relatively user friendly, and will not overwhelm larger rooms. ATC specifies room sizes of around 50 square meters for their use, but this is not a hard and fast rule. But they are heavy, and will need to be dispersed on rugged pedestal stands to ensure the tweeters sit around ear level.
They also need to be positioned a minimum of, say, 30cm proud of the nearest walls. You'll need considerable space to make the most of this set. Each Active 20 is equipped with a 150mm bass unit and a 25mm soft dome tweeter, with an onboard 200W amplifier in charge of the bass, and a 50W amplifier for the treble. Build quality is superb. The large area side walls of the enclosure are not parallel to avoid standing wave resonances.
The huge, curved C5CA centre speaker is fashioned from the same mould, but in this case there are two 150mm bass/mid drivers, and although the amplifier complement is similar, the speaker is a real back breaker at 45kg. Finally, the C4 subwoofer is a large, glossy, downwards firing design with an enclosed plinth which is fitted with a 30cm driver and a 1kW amplifier.
This is subwoofer design on a grand scale, but in practice it is easily matched to the rest of the system using a 'contour' control (essentially a mid bass tone control) in addition to the usual low pass filter, which with this system is optimally set around 70Hz. All speakers are equipped with XLR balanced inputs, which in this case were wired back to a reference Lexicon processor using phono-XLR adaptor leads.
Although designed to meet the requirements of a professional multichannel mastering suite, the ATC system is well dressed for domestic duties, with sober but high quality surface finishes and excellent detailing.
The massive perforated front grills on the satellites however are a bit of a giveway. They might not withstand nuclear Armageddon, but anything short should be OK. Much the same applies to the combination of drive units and amplifiers.
The former can be driven extremely hard without showing any signs of compression or distortion to indicate they are about to run out of headroom, and the amplification has enough muscle in hand to cope with whatever input is required, or this was at least the case in my listening room, which is somewhat smaller than the recommended floor area, but which still takes some driving.
What a concept!
Sonically, the ATC Active Concept 5 system is not the most subtle or expressive system around, but it is very open, unusually clean and extremely consistent, which means it can be played at a wide range of volume settings and still deliver the goods.
A low setting, suitable for late night use, offers the clarity necessary to follow the dialogue track, but as you might expect, the system really comes into its own at higher volume levels. In each case however the large and bulky centre speaker replays the investment with first class intelligibility. If anything it seems a little tauter and more focused than the Active 20s, though in general terms the voicing of the system is consistent.
The bass of course is the domain of the massive subwoofer, and although you won't be able to hide it easily in most surroundings, its performance is nothing less than superb. It goes deep and true, and reproduces pitch information with tautness and precision.
It never sounds as though it is working hard. It employs a very physical sounding transducer, one capable of doing full justice to high octane soundtracks like Terminator 2, or the busy and densely filled Lord of the Rings: The Twin Towers. The system is insanely dynamic, so-much so that routine explosive aural effects became distinctly disturbing.
The trade-off is that this taut sounding system can sound rather hard and unrelenting, and it is more than capable of showing where the audio engineering has gone awry, such as for example in The Incredibles, where the soundtrack plays a very distant second fiddle to the visuals (intentionally no doubt), and where many of the supposed special effects noises simply sound silly. That said, the extended frequency response of the Active 20s also makes them ideally suited for high resolution multi-channel music sources.
This Active Concept 5 system is a heavyweight in every sense. The centre speaker offers particularly striking intelligibility, while remaining consistent with the powerful front and rear satellites, and they are tied together with a strikingly effective subwoofer that is obviously capable of adding tremendous muscle and depth to proceedings, and perhaps slightly less obviously is capable of adding tonal variety and range, and enhancing the sense of atmosphere.
Along with the centre speaker it is surely the star of the show. But, as befitting its high-end design, this is also a system that doesn't suffer poor or inappropriate recording quality lightly. However, in full-flight it can deliver a powerfully memorable and exciting experience. In stereo terms these ATCs are not quite as precise nor as holographic as some more traditional high-end speaker solutions, though in a home theatre sense they can create a sense of envelopment and image scale which knows few peers.