Hi,
Just thought I would share my experience playing with acoustic foam inside of my 1801b. I had originally lined all sections of the sides, top and bottom of the speakers with acoustic foam (some Black Hole 5 and some Walmart matress pad), plus the polyester batting behind the woofer. I was always slightly bothered by a tipped up response, with a bit of harshness in a number of female vocal recordings. The speakers also sounded thin in larger rooms. I thought it was more related to the tweeter resistor values I had chosen. I listened to the speakers for about a year this way.
I looked through the board here and saw Dave's recommended stuffing brew. Not having remembered how I had stuffed the speakers, I took the woofers out and looked. I ripped out the stuffing that didn't adhere to the recommendation, which seemed to be not quite half of that I had put in, and must say that the speakers sound quite a bit better after doing so. I am getting more detail with mid-bass, richer bass overall, and better overall between the lower frequencies and the higher frequencies. The slight peircing of female vocalists has been reduced as well.
Alan
