I have to add to @dpac996 that it isn't just the integration of the ATC drivers, it's that they are all designed to achieve low distortion reproduction-this is NOT what most transducer designers aim for. Low Distortion Driver Units sound simple and obvious but it's truly a rubik's cube of objectives. For example, many performance attributes depend on other attributes and you cannot have all of them- you must choose. For example, there is a clear link between efficiency and LF performance in a driver: want more efficiency? Expect less bass- and vice versa. Low distortion requires very large motors (magnet structures) to exert more control over driver motion. These larger motor structures are very expensive to make and so not big sellers to speaker manufacturers who buy a lot of drivers. Because they don't sell well OEM, they are almost impossible to find and when you do they are 2 or 3 times the price of much more common cheaper drivers. Almost no one makes their own drivers anymore; years ago everyone made their own. ATC still makes all their own drivers in house in their own UK factory and doesn't sell any drivers OEM anymore (even though they began as an OEM manufacturer). This is their primary advantage.
A good example is the KEF story, who was one of the first to actively research and design/build their own drivers. One well know product they designed and built drivers for was the famed LS3/5a, the "BBC Monitor", supplied as a driver/crossover kit to various different [British] manufacturers who were licensed by BBC to produce this speaker for the BBC. So all of the early LS3/5a designs had KEF drivers and crossover inside, with no reference to KEF on the outside. Harbeth, Chartwell, Spendor and many more all used KEF drivers for their BBC speakers. BBC would license two manufacturers per year for these, which is why there were so many different brands of"BBC monitors". Some have even claimed some unique ownership of this design when it was really all KEF.
Most speaker makers today don't build their own drivers, they buy them,. Drivers require expensive employees and equipment to build and most manufacturers don't have enough sales to support a driver factory. So finding a low distortion driver on the OEM market like ATC is impossible-there too much price pressure to make enough money building/selling them to support it and ATC used multiple design innovations that are extremely difficult to copy. ( a dual suspension mid dome for example that is designed to work between 380Hz and 3500Hz).
High power drivers are unique too and yes, they are readily available OEM because the live sound speaker market is extensive and much larger than hi fi in sales. The most popular drivers in hi fi are low cost ones that don't break but are usually not at the bleeding edge of performance. Companies like Peerless, SEAS and Focal (and MANY others around the world) sell hundreds of thousands of drivers to all kinds of different speaker builders. More often than not the same drivers are sold to multiple manufacturers.
So the point to all this is the real secret to ATC is they "build their own" low distortion drivers which are properly integrated and account for a big portion of why they sound "different". A very common reaction to ATC is "wow, I hear stuff Ive never heard before" which is a direct response to hearing low distortion for the first time. This is what makes ATC popular in studio use, where it's a huge advantage to hear things others miss.
Brad
