I used these 2 subs in an active multi-channel stereo set up, using a DSP. These were my "proof of concept" subs; I've upgraded to 2 much more expensive B&W subs now. What I liked about these Energys is that you can bypass all controls, so your signal is directly coupled to the sub's amp without any pots in between. Yes, I am a crazy dragon chasing audiophile. I had to open up the smaller sub, then put the plate back on upside down (it still worked fine) but now the smaller sub won't power up. I looked inside again to find a loose connection, put the plate back on the right way, but don't no why it is not working, so this smaller sub is a throw in now. Someone with better tools may be able to find the issue. The price is just for the bigger sub basically. The S8 is (was) more detailed, about 3-4 dB down at the same volume, while the S10 digs down deeper, goes much louder, but is not as sharp. For the working, or both subs, $160 OBO. A friend in Victoria is the broker, so if I think you are serious enough, I can connect you to meet him for a viewing. Email me first! Thanks, Brian!