does anyone use subwoofers in their setup?

[brit]

ok so basically ive set my room up pretty well at the moment so that i have a pretty constant and linear system in regards to the sound output at all frequencies.

a 40 hz room mode means that at 40 hz, the system is 10 to 15 db louder than the other frequencies (and we all know that a 10db increase is actually double the volume)

ill take some photos over the weekend when im working on my system to demonstrate what i mean and how it looks when measured on software

Many thanks for this explanation - now looked up room modes on t'web - helpful. I am afraid that I have not yet ventured into the realms of room "tuning" (if that's the right word!) and possibly won't as it seems fraught with it's own set of problems - bass traps and all that. Anyway hope you resolve your 40Hz room mode .

David