I really appreciate your input guys!
Re-reading my initial post, I realise I might have gotten a bit hung up on sibilance. The sound is just a bit brighter than I would like, and I think that the sibilance is just a result of that. Also, I might be over-exaggerating when I say "sibilance" as it's really relative, I've got nothing to compare to. I don't want to give the impression that the situation is horrible (then toeing the speakers etc would hardly help), I just want to smoothen the high frequencies out a bit.
Originally Posted by Fruit
How about trying another specimen of an Audyssey microphone. The one you've used may be faulty; it might not have responded correctly to those frequencies so Audyssey tried to compensate.
Yes, that might be worth a shot, if I can find one.
Originally Posted by MagnumX
I got increased sibilance to the point it was objectionable the first time I ran Audyssey (compared to with it off). Trying again with the toe-in changed a bit on the front speakers (forget if i toed them in more or less, though) and moving the mic around a bit more seemed to get rid of most of it (or if I only ran Audyssey up to 250Hz in the editor). But if you get the increased sibilance with Audyssey turned off, it's likely something with the speaker and/or room having too much energy around the 5kHz-8kHz band (sometimes a bit higher depending on sensitive your ears are). Also, if you have the Audyssey editor, you can actually tailor the curve to drop a bit in that region to get rid of some or most of it. Adjusting the speakers and/or some absorption room treatments might help a little too if the room is very bright sounding.
I've re-run Audyssey a few times, but didn't actually change that much in-between takes. Adjusting the toeing of the speakers sounds interesting, it didn't even cross my mind that it could have an effect on this.
But regarding your last point about the Audyssey editor, please tell me if I'm understanding things correctly:
The NR1508 has a manual EQ that could probably help me out here, but in order to engage it, MultiEQ has to be disabled, together with DynamicEQ (which I really enjoy when listening at low volumes). But you are saying there is away to actually tweak MultiEQ itself, lowering the 5kHz-8kHz (or there around) band a bit?
When you say "the Audyssey editor", do you refer to the iOS app "Audyssey MultiEQ Editor app"? The app description contains a list of supported AVRs and NR1508 unfortunately doesn't seem supported. Is there another way of editing the curve on the NR1508?
Again, thank you for helping out!
Edit: The iOS app mentions this: "Enable/Disable midrange compensation to make the sound brighter or smoother". Can "midrange compensation" in any way be related to my problem?