I did extensive comparisons between the SCST and the regular one. The W15's go about 3 Hz lower than the ER15's, and I found the bass response a little cleaner at normal listening levels. At the same time, the midbass was a little leaner than the regular woofs, and the W15's can't be pushed quite as hard as the ER15's because they have a little less travel. Overall, the sound was certainly very detailed. I don't consider these rock speakers--the HT2 TL's will pump out a lot more bass before complaining--but they are very refined and clean, as you would expect with drivers of this quality.