"Will take [jsautter’s] advice and get some local expert input on getting the room right before moving on."
Kudos to you for going to an expert for advice on room acoustics!
If you don’t find someone locally, may I suggest Jeff Hedback of Hedback Designed Acoustics. Jeff is an award-winning acoustician whose services are still reasonably priced. I used to give out advice on room acoustic treatment until I went into a room that Jeff had done from afar (he doesn’t need to be there - he sends you files to play back and record, from which he does his analysis). Hearing what a real professional can do made me retire from being an internet amateur acoustician. The only product Jeff sells is very specific knowledge and advice for your room, and he can work within whatever constraints you have as far as room decoration and materials budget.
"Duke envisions correctly that speakers located at end of one long wall facing opposite long wall and only several feet from the side wall so there is a lot of asymmetry regarding speaker placement."
Thanks for confirming that.
"Could reorient speakers to face the length of the room but would block windows with nice view."
I once designed a custom pair of speakers for a couple whose window view was the Grand Teton mountains. I made ’em fairly short so their intrusion on that incredible view was minimal. But in that situation, there was no feasible option to position speakers on an unwindowed wall, as you have already done.
So let’s work with the view-friendly configuration you’re already using. I think the most problematic aspect is the asymmetrical acoustic situation with a wall (presumably treated with a lot of damping) on one side, and a big open space on the other. So my guess is that you get essentially zero highs surviving their encounter with the damping material on that nearby side wall, relatively little upper mids, and probably some lower mids (the effectiveness of absorption decreasing as the wavelengths get longer). Then I would guess that the room side has enough undamped surfaces that you still get some high and upper mid reflections from that side, after a nice long time delay.
(In general early reflections tend to be detrimental and late reflections tend to be beneficial, but in any case we want the reflections to have a spectral balance that is fairly similar to the first-arrival sound. If we absorb too much of the short wavelength energy, the reverberant field will have an overly dull spectral balance, which will tend to skew the perceived tonal balance accordingly even though the first-arrival sound has plenty of highs. A significant discrepancy between the spectral balance of the first-arrival sound and that of the reverberant field can even be a source of listening fatigue. I can go into more detail about this if you would like.)
The approach I would take in a situation like yours, where there is a wall on one side and a lot of open space on the other, is to start out with speakers that have very little early sidewall interaction (in the form of early reflections in the mids and highs) to begin with. One way to achieve this is with speakers that have fairly narrow and fairly uniform radiation patterns, along with a lot of toe-in. One beneficial side-effect of such speakers is, the tonal balance tends to hold up well throughout the room, assuming the room isn’t overdamped (which can remove too much of the shorter wavelengths).
"I do feel like there is a feeblenesss to the sound which may be related to room size and speaker placement."
A very large room requires a LOT of air-moving capability in order to get a good solid low bass foundation (ESPECIALLY if it is open into other rooms), but in return a large room will have inherently much smoother bass that a small room (and "smooth bass" = "fast bass"). I’m generally into using multiple small subs in smaller rooms as a way to approximate the in-room bass smoothness of a larger room, but you've naturally got that covered, so in your situation I’d lean towards two fairly high-output subs as a more cost-effective solution.
Duke
dealer/manufacturer