I also have an HK 3490, with the TV's optical out going to the receiver.
This same thing was happening to me, and I found a workaround for when it happens. Simply switch inputs on the TV back and forth, and it should be normal again.
Honestly, if you're not planning on doing any engineering with them, you're better off spending your money on a decent amp and passive speaker combo.
You'll get more quality that way, especially with a pretty hefty budget like that.
Quote:Originally Posted by mosi *edit*
I had a quick read on the LPF in the manual of your sub. You probably already know but if you have hooked it like rig->receiver(LFE out)->sub(LFE in) that LPF knob is basically disabled and the...