Still, I think it would be difficult to properly integrate the M66 with a Home Theater setup - there are no analogue subwoofer inputs. And even with the two-channel stereo analogue pass-through, you couldn't utilize any of the unit's Dirac Bass processing features for the four sub outputs. Even so, this might be my primary choice for a two-channel preamp; it's got such great features and performance.
I don’t see why that would be the case. It should be very easy to integrate and provide exceptional results too. The M66 has 4 sub outs with DLBC and ART is coming later, it’s going to make a fantastic job of integrating the L/R speakers with the subs and I can’t see any AVR doing a better job, certainly not one without ART. It’ll be head and shoulders better than your typical YPAO/Audyssey/Dirac only AVR/AVP.
The integration the M66 provides between mains and subs will be accessible by the AVR, as it’ll just see the mains as very capable full range speakers. So with the AVR set as large mains and no subs, then all bass from other small channels will be re-directed to the M66, which obviously in turn does its thing with the integration of the mains and subs.
Running the AVR calibration will also compensate for any delays when setting distances for all speakers. Then finally bypass the AVR correction on the mains as the last step (most allow this, all the ones I’ve had do and that’s YPAO and Audyssey based).
This setup is exactly what many people are doing already who run Lyngdorf 2ch systems as their HT bypass setups and it works very well, as RoomPerfect makes a typically better job than your average YPAO or Audyssey AVR.
Perhaps if you have a Storm or Trinnov you might not want to have the M66 sticking it’s ore in, but that feels a niche case. I‘d suspect most people (like myself) who are looking at the M66 and wanting HT bypass, are using far more regular AVR’s/AVP’s.