Now that is hard to believe with a properly calibrated system. My speakers are 106db/watt efficient and I can't hear hiss from that distance. I seriously doubt your speakers are more efficient than mine.

There are only two variables that would make the hiss more or less audible with a properly functioning 950:

1) The efficiency of the speakers. This is assuming there is nothing in the speaker's design which boosts the high frequencies beyond what would be flat response.

2) Proper calibration. If the calibration is improperly performed so that the 950 is providing more gain than is necessary for 75db SPL at the listening position using the internal test tone, then hiss will be audible.