Where to put budget

Trying to decide where to put my money for next improvement.  Deciding between surround back speakers, better subs, or room treatments. 

marantz 8802a on dedicated 15 amp line
(2) Lexicon rx-7 amplifiers on dedicated 20 amp lines 
oppo bdp 103
revel ultima studio 2 (left/right)
revel ultima voice 2(center)
revel ultima gem 2 (side surrounds)
(4) revel c783 atmos in ceiling 
(2) Svs pb 1000 subs
panasonic tc-p65vt60

room is roughly 16 x 17 but not a perfect square as front sits under a bay window.  System may be overkill for this room but five year plan is to make this room 20x28 so don't want to underbuy

what i am solving for:  I'd really like to get stand mounted gems for rear speakers to get the full 7.1 sound system set up/ full immersion.   I do have a decent set of revel 585 in wall speakersthat I could use for surrounds however I noticed a huge improvement and sound field when I switched from low end side surrounds to the revel gems. I think having gems in the back will me a good starting point from which to do anything else as I don't plan on upgrading them ( thinking of them as foundational). 

The base in the room is not how I want it.  I do have two subs and I have played with Odyssey I have moved them around but it still seems boomy.   Not sure if different subs or room treatments will improve this. 

Imaging is another area id like to improve for two channel but I'm a little constrained on how far out I can move the speakers.  Right now they are about 1.5 feet from back wall and 1 from side/back wall(it's an angle). Granted I don't have dedicated two channel going to these speakers but the equipment upstream is mo slouch and should give at least some depth. If anyone has recordings they'd recommend that have fantastic depth please advise.  My current budget is ~5k keeping in mind I don't want to do too much to the existing room as I plan to remodel it at some point. 

Bang for buck would be room treatment.  You have good equipment already so adding gems for the rear would be marginal. Not to mention you plan on expanding the room to dimensions that would be better conducive for a 7.2 setup. Additionally, you could use the room treatment could be reused after the reno. It'll likely address your low end coloration and deal with reflection to help improve imaging.

You're in very good shape now. Hold off on the 7.2 until you're in better room to appreciate it.

All the best.
Treat your room. Go to this link for more info: http://www.gikacoustics.com/

First thing, I don’t think the system is overkill for the room. I think you have some excellent electronics and speakers to enjoy!! The two downsides I can see are the quality of your subs and the room.

The SVS subs at $499 each are probably going to be a weak spot when matched with your higher end Revel speakers. The PB1000 is actually a pretty large cabinet, but only weighs 46 lbs. This tells me that they are using thinner wood for cabinet construction that isn’t well braced. I have heard other subwoofers that just rattle/vibrate the cabinet and it takes away from the sound quality. Also, at this price level, you are not getting a really good amp or woofer either. Don’t get me wrong, this is probably a very good value sub, but if you are listening at the $6k Revel level, you can do better! The boomy character of the sub can be from the cabinet construction, woofer quality or amp quality. Maybe look at getting a couple used JL Audio or Rel Acoustic subs. The JL e110 is a smaller cabinet than the SVS, but weighs more at 52 lbs. This means better cabinet stiffness, better woofer and better amp. There are many subs up for sale in your $5k price range -- JL Audio, Rel Acoustics, etc.

The other downside is your room. I have read that perfect square rooms are the worst scenario for acoustics. Your room is almost perfect square. You generally want a more rectangle room, but not a perfect rectangle, so your 20x28 is a good plan. If you have your speakers placed in the corners (which is the same as my room), you probably have standing waves bouncing between the corners. Check out GIK Acoustics website. My initial thoughts would be to stack two 24"x48" bass traps in each of the front corners (or the thickest acoustic panel you have space for). You can also put some bass traps with the FlexRange membrane in the rear corners. The FlexRange membrane will absorb more bass frequencies and NOT absorb the mids/highs -- used if you want to keep the high frequency energy in the room. I’ve found that there is a fine line where there is too much sound absorption. If you have carpeted floor, you can hit this point easily.

If you still feel you have problems with imaging, maybe start looking at upgrading power cords, interconnects, fuses.

One more comment. The things I suggested above can also be used in the 20x28 room, so the expense would not be wasted.

A couple recordings I can suggest (available in Hi-Res at HD Tracks):

Meloday Gardot - Lisboa (from album The Absence). The chime and bell instruments in this song are excellent for listening to imaging/depth. This song also has excellent deep/strong bass. Vocals and recording on this entire album is just outstanding.

Diana Krall - In My Life (from album Wallflower). I used this song to show how much midrange blare/ringing I have in a system. It’s very easy to determine this when you can hear the blare/ringing/boominess in her voice on this particular track. This really lead me to determine I had standing waves being reflected in the corners. My speakers are stuck back in the front corners as well (due to room size limitations). Other elements that can help clean up this midrange blare/ringing are improved power cords, interconnects and fuses. Some speakers are more sensitive to others. I have B&W Diamonds, which have a VERY strong midrange, so this problem is more apparent.

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I agree that your weak point in your home theater is you subs as well as wall treatment. I have an all Wilson Audio home theater probably similar quality your system. I have 2 JL Audio E110 subs and to be honest I only need one. When I shut of the second sub and close my eyes I can't tell the difference.  Will probably sell the second one if you interested.  But buy one first. I made the mistake thinking I needed 2. My room is about the same size as yours and I can feel the sofa vibrate during deep base levels. 
Good luck you have a great home theater. 
A room large enough to equally space the speakers from the listening position requires less, if any, processing to adjust for time/distance variables which can only be a good thing. 

You don't need a big room to enjoy the benefits of 7.1. More importantly is that the speaker systems tweeter/midrange units are matching. To a lesser degree but still important is the processors ability to setup and room correction.

I moved my 7.1 home theater from a smaller well dampened room to a larger less dampened room. While there were sonic differences attributed to the room size and damping the native or matrixed 7.1 remaines a more smoothly surround than 5.1.    


so Coming back to this I upgraded subs first  have made a huge difference. A pair of jl f212v2s absolutely shake everything and they are only at 20% do power. When I expand the room I think they’ll be perfect for double the space. 
From small ported old school subwoofers to modern sealed DSP units is huge upgrade. 
Did you ever reconfigure the rear and side speakers?