I have all new equipment now (H/K 330 with Athena bookshelf speakers). Last night my wife was out of town so I had a chance to really drive the system. I had it as high as -15 on the volume for some time while listening to a CD.
Is this too loud? I was afraid that i might be causing damage at that level. I read that the speakers should not clip but I'm not sure what that sounds like.
No, no, no. -15 is maybe HALF of the system's full potential. Especially with an HK, you can comfortably run that receiver at 0dB with anything but the loudest recording (Such as The Fast and the Furious, I'd leave that at -10)
Clipping refers to losing the top and low end of the sound wave, it sounds like a Bose subwoofer, muddy, inaccurate sound, you should hear it easily.
You could also hear a very high pitched sound during the loudest passages. It lasts for about a second, not very long. you shouldn't experience it at all, considering the receiver you are using and the power requirements of the Athenas.