Have you been at all bothered by a faint, low hum? I've read some complaints about this problem with the PSB Alpha PS1. Someone posted a response they received from PSB which said this was common among active monitors that employ class D amplifiers, but that the average listener would not notice the hum unless their ear was 1-2" from the speaker. For this reason, I've been looking for studio monitors that rely on older, class AB amplifiers, which some people argue offer better sound quality.