Look at the Galante Audio Rhapsody. It's not "smaller than a breadbox" but it is not as big as a horn system. Bass supposed ly to 50 hz, but I've not heard them; I have the larger version, the Symphony, which is 12 inch (98 db), rather than the Rhapsody's 8 inch (95 db). These do go pretty low (maybe 40) and sound great with a 2A3 amp in a "live" room. Brian Galante himself answers the phone, so service is first rate. Both models are occasionally for sale here on A'gon, which is how I got mine. They have a website: galanteaudio (all one word)
