Why audio sounds different in the Mountain Lion over 10.6

Hi

I just upgraded my system OS 10.6.8 to the latest 10.8.4, and I found that audio on the 10.8.4 sounds different.

I did some tests and I can say that audio when listening on the 10.8.4 has less bass content and the hi-mids are more agressive.

I running the audio studio on my Mac Pro and this was a big dissapointment for me.

Also I rendered audio file from Logic Pro 9 on the both system and they are the same, but when you listening on the 10.6.8 it sounds correct while on 10.8.4 sounds different. I have the same audio drivers from RME Fireface 800 on both systems. In tests I used identical Logic arrangement file on both systems.

I just don't like the sound on the new system at all. It is worse than it was on the 10.6.8.

I switched to the Snow Leopard again and I regret that I puchased your latest OS. Why it is done? Apple?