Wow. Nice size room and screen! Yayy you. 12 seats? Youre the proud father of a very large family, or you will be entertaining. Congrats either way.
Id think the biggest obstacle in erecting a good to excellent HT system, is when someone wants to mitigate the intended aim or goals of an actual home theater rig. Namely by adding this item to their designs ,
and for music as well.
That simgle compromise confounds me, and Im quite guilty of making it. My answer was provided me by separating things into individual systems. In your case perhaps via a pass thru option in the pre/proc.. in mine, just separates entirely will suffice
and maybe a tube CDP or TT.
Im sure you get this but Ill add it in to be sure. Audio and theater rigs are in fact very different animals. Only the components seem to indicate some correlations
though not the actual content of each. HT wants snap crackle, and BANG! Music wants sizzle, slam, and smooth extension. Occasionally some of the HT attributes yet in a different context
Its pretty hard to have breaking glass, gun shots, helicopters, missles, lightening, monsters and rain sound like they should when played in a musical system with the same impact they have in theater systems
the jump factor is a prerequisite for HT!
Ive never employed panels at all. My observations & auditions of them however dont lend them to providing HT excellence though IMHO. I say go cones throughout. Id say too, rethink the sub or subs for that size room. I believe two will be your best bet. I do like my DD 15 in an < 2800 cu ft. closed off room. Id also think about dipole surrounds to lessen the point source info and increase the information those sitting off prime real estate positions will receive.
Anthem does a good job with their pre/procs. Id go with other amp (s) though. Krell amps offer much for HT SUCCESS. Id also look for a pre/proc with MACROS, so you can configure all the lights, projector, amps, etc to initiate sequentially for a stunning presentation. Triggering on & off this and that, lights, curtains, screen deployment, etc. with but a single button push of the master remote sure makes you look like the expert you are
and the cool factor is off the scale.
My Onkyo receiver will do that so I assume a good processor should too.
HDMI 2.0 is now on the scene in limited fashion, so at least go with 1.3a there. A nice Blue Ray player isnt a lot of money now either. A good item there can do all the decoding for you via analog anyways. HDMI DOES give you great sound and video though too
and saves $$$. I run a 26 ft HDMI cable to my PJ without any issues at all. $60 - $75 via Blue Jeans incld ship. Also for other components at $12 - $20 depending on the lengths you may need. Only until I get well into my IC cables does the sound improve noticeably
and I do mean well into
HT Magic IIs, SR Resolution Refs, Nirvana SX, etc. Ive found Audio art a tuff to improve upon calbe, until you get well into the $400 > $500 per set range.
Personally keeping the Lynn speakers and adding to them if they are in fact acceptable is where Id start, unless you just want a change. Id focus on good strong amps, subs, cabling, and ease of operation.
Had you thought of built in wall speakers? The resultant cosmetic is super clean and expands the overall room size by not subtracting speaker foot prints and their resultant configurations. Id strongly think that way were I to do it all over again
or on the scale yours is headed.
With all HDMI cabling through out, power cords can become quite the thing at each end of the signal train
sources or amps.
Im very happy with what my HT array supplies me, and its not a full on HT rig. The Silverlines do very, very well in HT but save some impact from the most leading edge of information, given their Dyn Audio drivers. Musically however as the result, they remain quite enjoyable
with SS power. Better with tubes though for sure. The DD sub makes all the difference in the whole of things Ive always felt that they did have a great effect with HT RIGS AND SHOULD SOME COMPROMISES BE NEEDED, LOOK ELSWEWHERE THEN AT THE SUB WOOFERS TO GET IT..
For me to improve overall, only adding a 3ch amp, and maybe thereafter a dedicated processor would be required to really elevate things. BTW I used Canare 4s11 speaker wire and am impressed, especially with a couple runs of near 40 ft to the rears which the Onkyo receiver runs now with out issue driving Silverline SR 15s on Sound anchor stands.
Given your screen size, the audio does need to be as congruent as possible to fill out the effect. Pretty good duynamic speakers with good to very good amounts of power and a great sub or two, should do the trick.
One last note
its more of an embarrassment to explain why something isnt just right in the audio or video end when Im entertaining someone, so do spend time in there getting all the bugs out, and instructing yourself on exhibiting a seamless presentation for your guests by previewing the proposed content before they arrive
by setting .volumes mostly so you are hands free during the event when the lights go down.
Very good luck.