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What Makes ATC Loudspeakers So Special?


What Makes ATC Loudspeakers So Special?

Since opening our showroom in December, there has been one brand we stock that has clearly drummed up the most interest; a brand that seems to be generating a big following amongst audiophiles, musicians (such as Pink Floyd and The Rolling Stones) and the hi-fi press of late. You have probably guessed from the title of this blog post that yes, the brand I speak of is ATC Loudspeakers.

What Hi-FI? Magazine recently awarded the ATC SCM11 stand mount passive speakers the ‘Best standmounter £800-£1500’ prize  at their 2013 Awards show, claiming them to be ‘the most talented standmounters anywhere near this price’.

So, what is it that makes ATC Loudspeakers so impressive? Well, there was only one way to really find this out. A trip to the ATC headquarters and factory in Gloucestershire.

We got up early and excited to get on the morning train from Paddington to Kemble. Upon arriving we took in the fresh air of the Cotswolds and were set for the day. The ATC factory is situated in Stroud, it is a beautiful area known for its agriculture, it is a real calming and tranquil setting for the development of some of the best hi-fi equipment in the world. Maybe it is this reason that the ATC factory has such a relaxed and friendly atmosphere.  They even have their own chicken coop out the back providing fresh eggs year round.


But enough about the chickens, lets discuss what makes ATC speakers so great.

We were shown around the factory by the design engineers Ben and Richard. We got to see how every part of an ATC speaker was made, and they gave us really great detailed explanations of how and why. It was fantastic and so interesting.

The first thing to note is that all ATC loudspeaker systems and the majority of their components are handbuilt in-house. This really is quite rare for a UK speaker manufacturer, as most commonly companies will simply buy their units from other companies and put them into their systems or get the parts manufactured under licence. A company manufacturing their own components is extremely rare. ATC even hand wire their drive units.

The majority of ATC speakers (The ‘SL’ range) come equipped with ‘Super Linear’ technology. This is basically a method of eliminating the distortion of the input signal called ‘Hysteresis’ caused from the non-linear magnetic properties of the steel regions around the voice coil.  ATC has developed ‘Super Linear Magnetic Material (SLMM)’, a material that has high magnetic permeability and saturation levels and low electrical conductivity. Using the SLMM in their loudspeakers instead of steel has had a dramatic effect on the distortion. Ambient sounds and low level effects that were previously masked are now clearly audible and provide an enhanced sense of realism. The articulation of male vocals is markedly improved and pianos really shine.

Another feature of the latest ATC range that is unique is the new SH25-76 tweeter, from talking to Ben and Richard, I got a real sense that a huge amount of effort had gone into the development of this tweeter, and that they were supremely proud of it. For those of you who are not up on your speaker design, very few companies in the UK actually manufacture their own tweeters, more often than not companies will just buy in tweeters from foreign manufacturers and fit them into their speakers. Manufacturing the tweeters in-house has now given ATC the ability to fine tune the tweeters to exactly how they want them, and push the ATC sound to another level.


The tweeter shares technology with ATC’s famous soft domed mid-range drive unit and employs a unique dual suspension system suppressing rocking modes even at high power output levels. The ATC configuration of a short edge-wound voice coil in a long, narrow magnetic gap ensures exceptionally low distortion throughout its operating band and removes the need for ferrofluids, which can dry out over time, compromising performance. This is a unique concept which has proved incredibly successful for ATC. The SM75-150 soft dome mid-range driver has been utilised in ATC speakers for many years and has really set the bar for performance levels. With a usable frequency response for 300Hz to 4000Hz. It is able to handle this very important range without any crossover.


It is well documented that despite their success in the passive speaker market recently, ATC firmly believe that the only way to get the best sound you can from loudspeakers is to go active. I was intrigued as to why they felt active speakers were such a better option.

They told me that even a system which incorporates the best available stand-alone power amplifier will never achieve the performance of a similar active system. It seems like a big claim, but when you look at how the technology works, you soon see why this is the case.

For those not versed in the ways of active speakers, they are loudspeakers systems with individual power amplifiers built in for each driver. The low-level audio signal is first sent through a crossover to split the audio signal into the appropriate frequency ranges before being sent to the power amplifiers and then on to the drivers. ATC active speakers include active variable all-pass filters at each crossover point to correct the phase response of the drivers improving the imaging given.

Despite the obvious advantage of being able to control each driver sufficiently to its own needs, there are also some big advantages that active systems offer. The amplifiers in an active system are only required to operate over reduced frequency bands; because of this the intermodulation distortion (which is present in a passive system) will be dramatically reduced, by typically 20dB.

Also, in an active system the absence of a passive crossover, long cable runs and known amplifier damping factors all prevent the modification of the loudspeaker drive unit ensuring better controlled low frequency performance.

Finally, active speakers are just more powerful than passive speakers. For a given amount of amplifier power an active loudspeaker can be expected to produce approximately 6dB more level than the equivalent passive speaker.

Once we had finished the tour of the factory and learnt a bit more about the technology that makes them so great it was time for the really fun bit. The listening! We headed on through to the ATC demonstration room, inside there were the SCM11 passive speakers and the SCM50 Anniversary active speakers.


Listening to ATC speakers is a joy. They give a truly amazing neutral presentation of the music; it is an effortlessly natural sound. ATC speakers are fantastic all-rounders, it is extremely difficult to find downsides to their sound. They are clear and engaging with brilliantly controlled bass and beautiful highs.

As soon as they pushed play on the CD player I knew why the reputation of ATC Loudspeakers has become so great and continues to grow. This is a company that has been innovating loudspeaker design for 40 years and it doesn’t look like that is going to stop any time soon.

Oh, and the best part about this story is that since our visit we have got demo stock in of the SCM11s, SCM40s and SCM50As at our showroom, so I am now able to enjoy the amazing sound of ATC speakers every day. It doesn’t stop being exciting.

If you would like to try out ATC speakers, please get in touch by emailing contact@adairacoustic.co.uk to arrange a demonstration. You need to hear these for yourself.

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