I have a S15-d. Room volume has a massive effect on how the low end is presented with these cabs. Give it an eq bump around 50 or 60hz and it can carry a low B quite well in a small/medium sized room at resonable volumes, if you take it outdoors or into a larger room, particularly with a high ceiling and it's another story. It's probably one of the more musical cabs I've ever played, the roll-off on the high and low end is just right for "sitting in the mix" and staying out of peoples" way for many styles of music. It's a pretty amazing little box considering it's size, and the fact that it's basically a 30 year old design.