For anyone interested in such things, I have just finished making a transmission-line active subwoofer for use with my LS3/5As. \r\n\r\nI first saw the plans in the German DIY loudspeaker magazine "Klang + Ton" of October/November 2002. The thing stands 83.4 cm tall, 46 cm wide and - here's the good bit - only 13.8 cm deep. In other words, it can be hung on the wall or stuck flat under the sofa. The driver is an aluminium-coned Alcone AC 8 HE and the amplifier module (60W) a Detonation DT 50. The parts cost is EUR152, plus the necessary MDF. Only elementary woodworking skills are needed, but access to a router is necessary. \r\n\r\nI found it easy to put together and my first testing is good. It's at least as good as my old Yamaha NS-W1 subwoofer, and it's not only completely controllable with respect to frequency and volume, but its slimness allows it to be tucked away more easily than the squat, cubical Yamaha. \r\n\r\nProgress reports as I go on. If anyone is interested, have a look at \r\n\r\n[URL]http://www.rcmakustik.com/eng/rcm_rahmen.htm[/URL] \r\n\r\nGerman supplier Strassacker is now providing the necessary bits as a kit (speaker + subwoofer module + wire + wadding + screws)- for photos and details, see "Cheap Trick 198" at \r\n\r\n[URL]http://www.lautsprechershop.de/hifi/bau_ct.htm#ct198[/URL] \r\n\r\nand I'm sure they'd send it to England. The instructions are all in German (you get a copy of the "Klang + Ton" article), but drawings are a universal language). \r\n\r\nP.S. Progress Report (20.Feb.03). Now having lived with the sub for a while, I find I like it. It gives a nice bass lift without being obtrusive, just nice for my predominantly classical taste. I did try it with some jazz and rock, and again it performed well - the cone doesn't come flying across the room at you, but the bass is there, melodious and not just a thud. I also like the range of adjustment possible (frequency and volume). lowest frequency (50Hz) and about one-third volume works nicely in my room. Best of all, because of the slim dimensions, it slots nicely between two bookcases, out of the way. So, after 20 years of exemplary service, the Yamaha passes into honourable retirement (no doubt temporary) and I now have to decide what colour to paint the thing (still bare MDF).\r\n\r\n(6.Oct.03) Eventually it became dark brown. I initially did it with a tin of Breton blue that I had lying around the garage, but the Boss of Bosses objected that this did not match with the rest of the room, hence the brown. There is no evidence that either brown or blue has made the thing sound any better or worse or, indeed, any different at all. Pity, I was hoping to market speaker paint that tunes out electromagnetic radiation, damps the cabinet, makes the bass more melodious, etc.