How well do these things work?

I have not noticed any quality degradation at all. I use them to adjust not only the amount of midrange sound, but its location (left-center-right).

Best of all, I am not using the big, expensive L-Pads designed for stereo use. I just went to my home appliance store and bought three dimmer switches designed to be used for incandescant lamps up to (I think) about 150 watts. I think they cost about $4 apiece. As I recall, they give a maximum attenuation of about a factor of three. I am probably only attenuating by 25%.

tanstaafl.

"There Ain't No Such Thing As A Free Lunch"