I've set my system to 80hz, and lowered my sub. I tought that I lived 24h with my sub open yesterday, but when I went to check it, it was off (damned GF!!). I lowered it and turn it back on, I'm now in the first 12hours of sub usage (without any remarks). I'm curious how long it will last this time. I must have set the volume to zero, I can't believe it was on for 12 hours.