Close mic SPL measurements confirmed it was 10db as well.Is there not something else going on there then? The DNA-360 should be exactly 10 dB quieter than the 4594. If you go from an un-noticeable hiss at the seats to being able to hear it outside the room it must be way more than a 10 dB difference.
Even now the "hiss" can still be heard at the seats if you listen for it, but if you add 10db to the noise floor it's almost comical.
10db in the range our ears are most sensitive goes a long way.
I really wanted to use my CC4000 to power the BMS CDs. With the amp gains at max and the BMS plugged directly into it you had to get your ear within a few inches to hear the noise floor. Plug the MiniDSP into the CC4000 and whoa! HIIIISSSSSSSSS
I love the 10x10 for my subs, center, and the lower portion of the mains though. I'm using all 8 analog outputs on it.