I recently had the pleasure of spending the day at ATC's factory near Stroud. Everything about ATC is refreshingly un-corporate, including their very down to earth factory in the beautiful Cotswold hills in the south west of the UK.

I've long been an admirer of ATC's products and of their approach and, while I thought I already knew at least some of the answer, the question I had at the front of my mind was this: Their products sound wonderful but with most of the other high end monitor manufacturers I could think of there was a USP, a design feature which differentiated them from other available systems. Unique designs or materials, complex electronics or clever waveguides. ATC's speakers appear old fashioned and even a little dull. What's so special about them?

Simple Doesn't Mean Easy

ATC put good drivers together with well designed crossovers and put them in a box of the correct dimensions - is it really that simple or is that this approach isn't as simple as it sounds? 

A clue to explaining the approach taken by ATC lies in the name - The Acoustic Transducer Company. ATC manufacture all their drivers in house and on a tour of the factory the fact that so much of the tour was spent on the transducers themselves, specifically the voice coils and the magnet assembly was proof if it were needed that this approach, while simple, is far from easy. This approach requires attention to detail and decades of accumulated knowledge in how small, incremental improvements add up. 

Engineering Led Approach

This engineering-led approach extends right through the design, from voice coil to cabinet and is reminiscent of the purist approach to recording to which most of us aspire - Get the right sound at source, don't "fix it in the mix". In the same way, while DSP and speaker correction can achieve amazing things, the idea of getting it right at source just feels like the right way to do it.

ATC speakers aren't built to a price, they are built to a spec. The family sound is consistent through the use of high quality drivers and crossovers. I'd never understood the naming of the products but the number refers to the volume of the cabinet in litres. For example the SCM25a has a 25 litre cabinet. With increasing size comes greater bass extension and SPL but the family sound remains. Interestingly the smallest speakers, the SCM20 and the new SCM12 differ from the rest of the family in that as well as being 2 way designs, they are in unported infinite baffle cabinets.

Quality Control

The test area for drivers is where components get tested for consistency and durability. I took a short video of a 15" driver being driven to maximum excursion and the travel available in these drivers is surprising. As someone who has witnessed the death of more speakers than I care to remember I have to say I've never seen a driver throw itself around a room as much as that and survive!  

SCM12 Pro

The new SCM12 is the most affordable ATC monitor yet and as a passive-only design it fits perfectly with the new demand coming from post rooms upgrading to accommodate higher channel count formats such as Atmos. In scenarios like this, passives have distinct advantages in terms of ease of use and not needing to run power out to multiple active monitors. 

Cabinets

Apart from the now discontinued SCM16A which had a cast metal cabinet, all ATC's cabinets share similar wooden construction. The 2 way monitors are infinite baffle, the larger 3 way designs are ported and none feature any of the ubiquitous waveguides found on so many other monitors. This lends the ATC monitors a distinctly old school appearance. The logic behind waveguides is to control the directivity of the frequencies exiting that driver. Keeping sound away from walls will, in theory, reduce the influence of the room but as low frequencies and much of the midrange is effectively omnidirectional this can only be achieved across part of the spectrum using waveguides.

The edges of the flat baffles are bevelled, sharp corners cause the sound to re-radiate from the edges causing comb filtering, and in the largest 3 way models the arrangement of the midrange and HF drivers is offset to ensure a different distance to the cabinet edge in each direction, even if it does make them look lopsided.

Listening

I've heard big ATCs before and they sounded jaw-droppingly good. The issue with experiences like that is I'm never sure how much was the speakers and how much was the room. The listening room at ATC is principally aimed at their hi-fi products and as such resembles a large living room rather than a properly treated studio control room.. This room has a couple of absorbers on the mirror points on the walls but apart from that is plasterboard and carpet.

Even Dispersion Gives A Wide Sweet Spot

Listening to a pair of SCM100s the reproduction was clean and effortless. Headroom and bass extension weren't even worth thinking about, imaging was even and solid. It's all there. The biggest impression they left on me was how obvious the benefit of their even dispersion was. I mentioned earlier about how they don't use waveguides. Because of this there is little difference between the reflected (off axis) sound and the direct sound.

I'm sure this contributed to the spaciousness and width of the soundstage. I'm also sure this helped provide the wide sweet spot. As I moved from left to right there was a smooth crossfade from one speaker to the other, as there should be. So often I find that with minimal movements I lose the contribution of one speaker completely.

Simple Done Right Gets Complicated

My initial thoughts when visiting ATC were that if there's no secret to what ATC do, and it works (and it clearly does) then why doesn't everyone do it?

There are of course other high quality monitor manufacturers who share ATC's approach and I'm sure they have all found that it takes a long time to identify and improve the details which all have to be in balance with each other to build products like this.

A new technology or a revolutionary product offers something to shout about. But while those brands are releasing dodecahedral speakers with graphene tweeters, ATC will be quietly identifying a new formulation of ferrite powder to make inserts in their ceramic driver magnets to minimise eddy currents in the flux... You see what I mean? It's not revolutionary whizz-bang stuff but each of these things add up. One of the most noticeable things compared to visiting some brands is that ATC are so open about what they are doing, probably because they know its not about what you do but how well you do it!

Many thanks to Ben Lilly at ATC for showing me around.