[Jason Lawrence]

We use the Martinsound MultiMax EX system in our studio. It has multiple surround inputs and sources as well as multiple speaker outputs, including small mono. It also does downmixing from surround to stereo and helps you calibrate with the built in pink noise generator.

We have been really happy with this box. We bought ours for about $3K at Sweetwater.

Their site:
https://www.martinsound.com/pd_mmu.htm

Sweetwater info page:
https://www.sweetwater.com/store/detail/MXMLR/

Hope this helps.