The ATC Loudspeakers
SCM0.1/15ASL Sub features ATC's incredible SL Driver, a 375mm (15 inches) diameter woofer, it is the largest of the SL driver options and offers the lowest 3rd harmonic distortion of any large woofer we know, typically reducing it by 35dB. A massive built-in 1000W ATC high speed amplifier delivers over 118dB spl at 28Hz, an amazing feat. This sub is floor loaded to couple with almost any room properly (far better than any front loaded type sub). It also offers a nice user interface that addresses Billy Woodman's philosophy of "no bass management". The ATC sub has a dual XLR (L/R) input, an amp gain control, a LP filter with user selectable frequencies of 2K, 180Hz, 120, 90, 70, 50Hz. There is also a "contour" control that enables a peak type filter (boost) into the amplifier at around 100Hz if you want to compensate for AC3 or source deficiencies.
ATC recommends no "bass management" or, no roll off for the main speakers when used with a sub. This bass management filtering artificially colors the main speaker sound and introduces filter/phase problems. ATC's thought is that bass management was largely created to protect woofers in tiny satellites, not to improve overall response or transition between sub and mains. Run the main speakers full range and the sub at the widest possible bandwidth, then lower the LP filter freq to the sub from there. This generates a nice result and creates a smooth transition between mains and subs.
The ATC sub package is flat to 28Hz and is very clean. True low distortion woofer output below 100Hz is a thing of beauty and we've heard it ONLY in the ATC. Do not expect to be "knocked down" with huge quantities of bass. Much of what we think is massive bass is really just loads of distortion at 200Hz to 300Hz! Sometimes this distortion can approach 40 to 50% of the total sub output! So word to the wise, do not buy this ATC sub for showing off to clients. It is a precision tool and engineers window into the "below 100 Hz" world of a mix; a near perfect mate to ATC mains. If you are making judgments on bass content we see no other way you can to do it properly than with the ATC sub.
A single ATC SCM 0.1/15ASL will deliver output SPL of 118dB (1W/1M). IF you need more output you must add units. A single 1-15 sub is 118dB SPL, 2 is 121dB SPL, 4 is 124dB SPL and 8 is insane!
ATC also makes a SCM0.1/12SL sub which sounds great but is designed for lower output and smaller rooms. It is fine for small production rooms but we do not recommend this unit for the typically larger studio control rooms.