I'm planning on slowly upgrading the stereo in the bedroom, which at the moment consists of a personal CD player and reasonable pair of JBL PC speakers. Can anyone recommend a musical sub for <100? Is there such a thing? It needs a line in and line out port so I can connect the smaller speakers to it. The plan is to later add a more capable small hifi like the Denon DM31 and some better speakers, so the sub ideally will need a normal rca connection. I'd like to be able to hide the sub under the bed so it needs to be less than 12" high (and forward-firing?), there's not much space available! Not asking much am i? Are there any "cheap" subs fit for this? It doesn't have to move the earth, just give me better bass response at medium volume.