I've noticed some intermittent noise coming from the front left speaker (B&W 685) connected to my Denon 2311. It's not present in either of the direct modes, just when the processing is used. It's not really that noticeable when there's sound coming through but I sometimes notice it during quiet passages.
It doesn't come from any of the other speakers or sub. I've tried turning all other electricals off close to it or the speaker cable so pretty sure it's not picking up noise from anything.
Does anyone have any experience of this? Is it just a 'feature' of using surround processing or is more likely some sort of problem?