Nestled in rolling countryside on the edge of the Cotswolds, it would be easy to mistake ATC’s headquarters for a collection of farm buildings, rather than home to one of the world’s most respected studio monitor brands. Technical sales manager Ben Lilly has picked us up from the train station, and after a short drive and a cup of tea we’re straight on to business with a tour of the factory… ATC are one of very few speaker manufacturers who make all their drivers and amplifiers in-house, with all other parts made to their own specification within the UK. This self-sufficiency means they are in complete control of the technology and quality of their components, enabling them to optimize all aspects of their speaker systems from start to finish. We’re first shown into the winding room where the voice coils for all ATC drivers are made. A gleaming robotic assembly line rapidly churning out coils into a hopper basket? Nope… instead, we’re ushered into a traditional engineer’s workshop redolent with the smell of well-oiled metalwork and solvent. One side of the small room is stacked with neatly arranged reels of enamelled copper wire and on the other, Ros is meticulously building each individual coil on what looks to be a fairly antiquated winding machine… The copper wire is first flattened on the same machine that has been flattening ATC’s copper wire since 1976. Why? Because edge-wound flat wire can be more densely packed… 30% more copper in the gap than a comparable coil wound with round wire means greater efficiency (less amplification to achieve the same SPL). It also means fewer air gaps, and less air means faster heat dissipation in the hard working coil resulting in less distortion and a more linear response. After the coil has been wound, the relatively fragile and sticky glued assemblies are oven baked to set the adhesive hard. Once cooled and tested, they’re ready for the next stage… As we progress through the manufacturing stages and see the drivers gradually take shape, with the finished coil being built up alongside other diaphragm components (cone, spider, rubber surround etc), it quickly becomes evident just how much attention is paid to each step in the process. Ben is a mine of detailed technical information and explains how the manufacturing process has been continually tweaked and improved over time. The largely mature and clearly long-standing workforce is, to a man and woman, happy to discuss their work and there’s a clear sense of pride in doing things properly with a real eye for detail. What they used to call craftsmanship… After completion of what ATC call their “software” components, we’re shown the magnetic “hardware” and a slightly intimidating hand-operated magnetizing machine where the steel cores that form the driver magnets are individually charged. We’re assured the business end of this is contained inside the machine’s small circular cavity, but I can’t help taking a couple of steps back with my phone securely planted in my back pocket. You can’t be too careful! In the Quality Control rooms, we see finished tweeters being tested. ATC use a unique dual-suspension tweeter design incorporating many of the design features of their mid-range drivers. This allows ATC to achieve a very narrow magnetic gap, which results in exceptional directional control of the voice coil and significantly reduced rocking modes – a torsional motion in the diaphragm that causes unpleasant sounding enharmonic distortion. The tighter air gap also allows more efficient heat dissipation away from the coil. Tweeters are individually calibrated and the results recorded and filed – any drivers that fail the stringent tests being destroyed. The very tight tolerances obtained mean you should be able to directly swap components regardless, but these logged profiles mean that if you’re unlucky enough to fry a tweeter, ATC can supply a replacement that is as close as absolutely possible to the original. Like I said… attention to detail. And if you’re ever worried about blowing a bass driver – you would have to be going guns to outdo the stress tests ATC put their drivers through. All bass and mid drivers are stress tested with a high-amplitude sine wave signal. This checks for rub and buzz, spider misalignment and reveals any loose particles that may have sneaked their way into the motor gap during assembly. It also pre-stresses the unit significantly beyond its normal operating range to expose any potential issues that may develop further down the line. You might want to turn your speakers down for this bit… Back in the main building, we’re shown how the power amplifiers are hand soldered, assembled and soak tested before being installed into the cabinets. The finished speakers are QC’d using a Klippel diagnostic system to ensure they fall within ATC’s “golden reference” spec before being released for shipping as a matched pair. And in case you wanted to know how to clean your ATC studio monitors, they have an opinion about that too... a J-cloth and Windowlene for the best results! Perhaps the most impressive part of the tour is a clearly demonstrated desire to hunt out marginal gains wherever possible – anything that helps achieve the best possible product. I ask Ben which other speaker manufacturers keep him up at night. Tellingly, he explains it’s not something that concerns him – at ATC they just want to ensure they make their product in the best way they can.

Full range monitors… Free range eggs

And you have to love a company that keeps a chicken run tucked away behind the carpenter’s workshop. ATC staff can buy half a dozen of Gloucestershire’s finest organic free range eggs for £1.30… and with Sainos charging £2.15 last time I checked, that seems like an eggs-ellent deal (ouch!)

Final thoughts…

It’s easy to forget that, in the scheme of things, audio professionals constitute a very niche market. The manufacturers who make our equipment are often small companies like ATC, formed by passionate enthusiasts who aim to contribute something innovative and useful in the pursuit of audio excellence. It is hugely refreshing to spend a day with a manufacturer where the only talk is of discussing the myriad ways they seek to optimize their product… profit margin, cost/benefit analysis and turnover aren’t mentioned once. Make no mistake… this is a no-compromise technical product. Spending the day at ATC, it’s easy to appreciate the price of these monitors. This amount of time-consuming, labour-intensive hand construction and sheer attention to detail doesn’t come cheap. But when you think that every adjustment you make in your mixes is judged on what you hear through your monitors, it’s the one part of your system it pays to get right. Thanks to Ben and everyone at ATC for a very enjoyable day.