Your thoughts about ATC loudspeakers

I’m interested in the ATC SCM-40 from their HiFi series and would like to hear from people who have owned or spent a lot of time with ATC speakers. This is a fairly new model and may be a bit of a departure from their classic sound.

At the show in Newport last weekend, I was quite taken by these speakers. I went back the next day and heard the same things that I liked about them, but a couple of red flags also went up:

Microdynamics – not sure these speakers do them well and microdynamics are critical to communicating inflection and nuance and to making music sound alive

Imaging, specifically wrt depth. Nothing much outside of the plane of the speakers, so recording venue info is not there and even instrument and vocal body may suffer a bit.

Were these shortcomings of setup or associated gear, or is this what ATC does?
Ag insider logo xs@2xdrubin
ATC speakers in general are not easy to drive (unless you’re buying their active version ) buying their pasive speakers can get you to a serious problem because hungry wats speakers require powerfull amplification and this cost money, a lot of money.If cost is no object ATC can be excellent choice but most of us have a limited budget so we have no choice but to look for other brands with more efficient speakers.


Agreed. Good points.

ATC tend to go well with big Bryston amps or amps around the 200+ watt range. Definitely not suitable for anything under about 150 watt tube amps like big Audio Research or Macintosh amps.

ATC active amps are solid state with MOSFET output stages and biased such that they are Class A to 2/3 power. So active ATC is really the best way to go with this particular brand. And this brand is best avoided by those folks who prefer to drive their speakers with tubes or those who want more personal control over the sound.

And there is No Best Speaker suited to everyone! Only the best speaker for each individual within the context of their preferences, requirements and experience. One can only say that ATC are a world class speaker chosen by many (but not all) golden eared professionals with rather specific musical requirements for a truthful presentation that allows for ease of important mix/mastering decisions of the source master tapes/files.

I'm the OP of this thread and I'm pleased that it's yielded an enduring, informed discussion. As for me, I remain interested in ATC but have not made a move. One concern that's emerged for me is whether ATC speakers do well at low volume listening. Some don't, as you know, and that could be a non-starter for me. I'm also interested in the comparison between the v19 and the v40. My local dealer prefers the 19; however, he uses a subwoofer with both models, which I am not likely to do. Anyone compared the two?


ATC are voiced for realistic live music levels. So turned down to levels of a TV or a radio and they will sound anemic in bass (see equal loudness curves). You can of course simply boost the bass at low levels and it will sound great.

ATC bass is not resonant like some ported designs and this means bass will not be boosted or bloated even when cranked.

ATC help sound engineers design the mixing to sound good at a loudness level that suits the music. Obviously the normal loudness listening level is different for various genres. Anything intended to be listened to at moderate to low levels needs a bass boost and anything intended to be listened to at Rock highest levels needs to have less bass.

If you always listen moderately or softly then much of the benefit of ATC massive drivers (that are low distortion even at high SPL) is going to be wasted or remain unused. Our ears can handle a huge dynamic range and much of the detail can only be entirely heard at realistic levels. If you play at a maximum of 80 dB SPL at the listener then you have around a max of 40 to 50 dB dynamic range audibly available above the noise floor. If you play such that the highest sounds are 110 dB SPL then you have an additional 30 dB of audible detail that was not available at low listening levels. It is key to understand that by cranking it you are able to hear a further 30 dB below the noise floor at a soft level and only a very robust over-engineered design of speaker can deliver this. Large ATC are like 70 dB down in 2nd and third harmonic distortion throughout the mid range - this is very clean and this is why the SCM 40 will sound clearer than the 19 which has the 3 inch mid grafted onto a 6 inch woofer.
My philosophy is to build the most accurate system possible and then if there are situations where I want to deviate from neutral for one reason or another, deal with that separately.  You can get a digital equalizer that can be used to improve low volume playback.  You could get a syrupy sounding tube pre, or maybe just a tube buffer, if you have things you like to listen to that way.  There's nothing wrong with changing things when you want a different sound, but if you start with something that is pretty far from neutral it'll be hard to guess what will happen if further color is added.