HT and 2 channel in same room? 1 or 2 systems?

Mine is in the same room. If you have the proper space and acoustics why not. Ht receivers especially high end receivers have a “pass thru” circuit that allows for isolation of each pre amp and respective amps. I’m my scenario it works out great. 

@Johns21,

In my view,+1 Carlsbad configures it exactly how you may want it. I do it the same. Bypass for the avr, means one volume control for the entire theater system or use a second preamp input and use two volume controllers as sometimes the ratio of fronts to surrounds you will want to vary on the fly.

This is an excellent question and very appropriate for me.  I was very excited this morning to read the responses and potential solutions offered by the Gon’ers as I am currently building and trying to figure out the same issue.  IMO with enough research and asking enough questions to the right people, there is always a solution even if it’s a compromise.  But life is all about compromises that you can be happy with. For the OP, I believe the solution is a preamp with HT bypass and sub pass through and is neutral enough to not color the tube amp.  I would keep the tube with the LaScala’s.  I’ve heard them in a room your size and they are one of the top 5-10 speakers I would choose to try in that room.  For the rest of your system, or systems, of integrating subs across HT and 2 channel, here is what I intend to do.

In a mixed use dedicated room,  14x22 fully sound controlled to the best of my ability, I have prewired for 7.4.4 + 2channel mains and riser platform acting as bass trap/ theater seat riser.  I have acquired almost all of the following gear.  I lack the Pre with HT bypass and the DIY subs.  If I am overlooking something obvious, please let me know why this won’t work or you feel that the compromises seem more than it’s worth.  Also, this is my critical listening room, so the compromises need to be minimal.  
Denon x4200h AVR with Rotel amps driving LCR, SS, RS and Atmos. Sub out to miniDSP for passive DIY subs at side and back of room.  Front wide pre out to 2 channel Preamp with 2.1 HT Bypass to amp driving another set of LR as 2 channel mains and  acting as Front Wides when in HT mode.  LFE from AVR also sent to .1 on Preamp bypass into REL subs in front of room.  REL subs also wired high level from 2 channel amp for 2 channel listening.  Video sources sent to AVR and streamer sent to 2 channel Pre.  Room treatments are next but I obviously need to have the system setup and REW before I start on that.  The one issue I haven’t solved is the fairly large projector screen as a reflector between my mains.  My only option may be to use a curtain to pull over the screen for critical 2 channel listening but one thing at a time.  My room is not huge so compromises of speaker placement is a very big concern of mine, but it is what it is and a viable solution will present itself with enough trial and error and enough equipment in and out.  Hopefully, responses to this will help the OP as well as me.  

@speed121 

Congrats on your attention to detail. I would only add two things. Get a laser pointer/measurer and try and make the MLP equidistant between the front and rear channels. The second thing is HUGE, get the paid upgrade for Audyssey MULTQ-X and the calibrated mic. Your concerns about the screen will likely be a non issue and the tweaking abilities of this upgrade will let you adjust as needed. IMO wide channels are more important then height channels for an immersive experience. make sure to get them as close to 60 degree angles as possible:

Hi Johns

For many years I tried to build a 2 channel system using my home cinema amp but gave up in the end. The DAC in the AV amp simply isn't up to it. I proved this to myself when I bought a Audiolab MDAC+, the difference was amazing. Detail and Soundstage were the 2 biggest differences. This set me off on a bit of a hifi obsession, I now use a DCS Bartok as a DAC through BHK 300 mono's into Kef Reference 5's. Non of these form any part of my AV set up.

For that I use an ONYKO TX-NR 3030 Atmos 11.2 receiver, Kef Ref 4 speakers, Kef Ref model 200c centre, 4 x Kef Q95 Surround speakers and 4 x Kef Q95 Height Speakers and A kef TDM 45 Sub. Epson Projector.

I am fortunate to have a decent size room to accommodate all this stuff, 21' x 19' with a 13' ceiling height. My HiFi system sounds so much better than the AV set up that I spend 95% of the time listening to music now, via Qobuz.

So, to answer your initial question, Yes you definitely need 2 separate systems, especially if you want the best out of your 2-channel set-up

Mark