most accurate loudspeakers....

Well loud yes but at what distortion level? A car horn can produce a 120db tones anytime. That is why you do not use PA speakers in your home. There is a big difference between the need to simply amplified and the need to accurately amplified. And when I say accurate, I mean liner FR and low distortion. Two things that PA systems are not very good at.

Roypan -- the measured distortion levels produced by ATC at high spl are comparatively low (unlike many PA systems). That's actually a useful thing.

escalante femonts

Gregm- I have my doubts. The only independent measurements I have ever seen of an ATC speaker were not very impressive. On the contrary. The distortion levels of their dome midrange was completely unacceptable (Stereo Sound issue 155).
I must say, that to my ears, that is how they sound as well. Especially when driven hard. They get harsh and glossy sounding as soon as you push them.

Roy,

I have not seen the plots you refer to so perhaps you could PM it? Your observation that ATC powerful mid domes can sound harsh when driven hard is a fair one. ATC claim IM distortion in the inner ear affects hearing at extreme levels (could it all be marketing hype as you suggest - I don't know). What I do know is that they sound too harsh on certain recordings like Green Day and other hyper compressed modern CD's (ONLY when played extremely loud of course). Bear in mind, that it is principally the dispersion pattern of a dome mid which is desirable and not low distortion levels. It is well known that large dome mids are difficult to build with distortion levels as low as regular cones - ATC actually uses two suspensions to help maintain VC alignment.

So playing loud while maintaining accuracy/linearity similar to what can be achieved quite easily at low level, as you point out, is extremely difficult to achieve (exponentially difficult in fact). This is why most cheap headphones are very impressive in linearity and distortion figures compared to speakers! This is why there are a great many excellent speakers that go up to 100 db SPL.

Incidently, your Magico's apparently use constrained layer damping in the mid range cone. I read somewhere that ATC is doing this too on their entry line...lighter cones, smaller motors and yet well damped...a recipe for good sound to me! I must admit the Magico V3 sure looks impressive and the Ultimate is so extreme I doubt I'll ever see one let alone hear one! You could do us a favor and post pics of your Virtual System as I bet it is accurate ;-)