timmydos

Just thought I'd add to this comment - I have the exact same thing happening and it started around a month ago on my Promedia set from around 2005. Intermittent, but frequent, hissing at various levels. I have unplugged all speaker connections between PC and Sub but it only goes away if I cut power at the Control box or power outlet.I tried re-routing the power cable to reduce interference, with no effect. I tried all manner of software settings in Windows. I'm baffled by it and would also love to get in on any expert suggestions.These speakers are great, so I hope it isn't an end-of-life scenario. Tim