What does Auro Upmixer do exactly?

[polmuaddib]

I am new to Auro. Bought Denon 4500 AVR few days ago, posted about it in different threads. Had a chance to listen to some Auro 3D upmixes from 2 channel music and i must say it sounds much better then 2 channel version. My subjective impressions are: volume increased as the most active channels are LRC and front height channels. I dont' hear much from surrounds. Also i hear HF spectrum amplified. Nice. Some drawbacks i find are that S sound is unbearable. It is amplified unreasonably. It really bothers me. I feel that dynamic range is reduced. But that is my impression only.
So, does anybody know what the Auro 3D upmixer is doing? Changing frequency response, dynamic range, loudness, favours some channels???
Thank you.

 

[phoenixdogfan]

One of the things initially promised by Smyth Research on its release of the A16 Realiser was an Illusonic 3D Upmixer. If anyone know what the Illusonic does, in addition to the Auro, I'd appreciate being informed about it as well.