ATC SCM40

@steve59  With all due respect,  I work with ATC so I am terribly biased in their favor, but I have worked in the speaker industry for 40 years with many different manufacturers including those with large engineering departments (such as JBL).  I have seen a lot and I know the OEM market a bit and how manufacturers make money there.  The ATC mid driver is not comparable to anything that I have seen on the market over the past 40 years and even today, it still stands alone.  The mechanical design and execution are beyond anything possible in OEM as it would be impossible to turn a profit on it.  No one would pay $1400 for one and put it in a speaker.  It has features that are not easily explained to a speaker owner as they are a physics and material science master class.  A far larger motor, a much greater stability in linearity due to two [dome] suspensions, lower distortion especially under higher dynamic ranges (115dB potential in the SCM150 to reproduce enormous peaks).  It is completely hand made to get the results the company owner wanted.  

You cannot build that driver on a machine and the techniques to build it are so nuanced that there is no copy available from anyone.  I would cost a bloody fortune to reverse engineer and you couldn't sell enough of them to make it worth it.  That's why there is no equal out there.  I agree there are a few 3 inch mid domes that look like the ATC from the outside.  But remove the driver and look at them vs the ATC side by side and there is no comparison between them-from a design and construction point of view.    And DSP cannot fix distortion inside the driver- once it's there, it's always there covering up details.  .

Brad

@lonemountain I agree, the ATC dome mid is overall the most impressive midrange driver I’ve ever heard.  Question for you — I’ve read the mid they use in the 40 is different from the one used in the 50 on up.  Can you explain the design and performance differences?  My understanding is a major difference is in power handling capability but wondering if there are some sonic differences too.  Just curious.

@soix +1

@soix

There are two versions of the mid driver, the "normal" one in the 40 and the pro 25 and pro 45. Then there is the "S" version (for super dome), which is in everything else (50 on up). I remember when I was first getting to know these parts and found out the recone kits for repairing both were exactly the same. The only difference between the two was a larger magnet (larger motor) for greater power - which relates to higher power handling and greater dynamic range. So from a technical point of view there is only one ATC mid dome, with a version that employs a larger magnet. Everything else about it - the coil, the gap, the frequency response etc- is identical. The two versions sound exactly the same, the "S" version in the 50 on up is just capable of more output, more SPL, which matters in some situations but not all.  

Brad

@lonemountain Great info.  Thanks!