I haven't found that 18" yet. Anyway, I was reading a review a while back about the effect of increased bass output in small listening areas. The article was primarily about automotive sound systems. He displayed a response curve in open air and superimposed a curve obtained inside of various cars. A small car interior had about a 30db max boost starting below 100Hz that he called the "pressure pot effect". Do you know at what point a room will exhibit this effect? Say, below "so many" square feet we have a noticable increase and above this area is negligible. I have a little over 250 square feet. You said that generally a 500 square foot room would be the minumum for a cornerhorn; so what happens in a room 1/2 that size? Do I lose the bass extension because the sound wave doubles back and cancels? I sure don't want to waste my time if another enclosure design would give me better low bass extension. Until I can get the proper 18" JBL driver to experiment with, I will probably turn my 4508 (4648-8A) into the corner. Its a LOT better than nothing.

Richard