Can I improve tonality and keep room the same?

Hello, I’ve never posted on Audiogon before, but have lurked for a long time and been indirectly helped much from the experts here. I’m working on improving the sound of my system, and am humbly hopeful the Masters here may possibly be able to help.

My latest 2-channel system is light years ahead of my old one in terms of quality. Speakers are Revel Salon2’s, powered with Bel Canto Ref 1000 Mk II, through a Bel Canto Pre3. Sources are a LogiTech Transporter for digital, and a VPI scoutmaster with Clearaudio Maestro for LPs.

The Transporter and Bel Canto’s are all connected with XLR interconnects (not expensive ones). My “line stage” is an old Marantz 7C. I’m considering upgrading the Transporter to a Modwright. Also maybe replacing the Pre3 with a tube preamp.

The room is 20’ X 14’. Floor has wall to wall thick carpeting. The ceiling slopes from 10 feet high on the front speaker wall up to 25 feet or more on the back wall. It's a painted "popcorn" ceiling. It’s like the top of a huge horn. To the right of the listening position, the side wall is a "half wall" that extends a couple of feet above the top of the speaker.

I'm not following guidelines well for placement and room use.

It’s a dual-purpose room, with home theatre, quite a few fairly stylish furnishings, and I’m sensitive to GAF (Girlfriend Acceptance Factor).

I know it’s BAD, but I have a large flat-panel TV between the speakers, and a wood furniture "tower" (mostly just an open frame) on the outside of each speaker. The speakers are out about a foot from the front of the TV (this helped much with the sound). Each speaker sits between the TV stand and a “tower”. Each “tower” is about 2’ wide, so the speaker sits “out” from the wall about 3’, but it’s next to the darn tower. This pretty well fills up the front speaker wall.

But – perhaps surprisingly – the 2-channel sound is, at least to my ears, close to being completely acceptable. After hours and hours of experimentation, I found a very-sweet listening spot about 5 feet from the back wall, between the speakers. The balance changes dramatically when I move my head, just a little, side to side (not sure if that’s good or bad…).

The problem is… in 2-channel, the bass is fairly lean (which I don't think is attributable to the Salon2's...) and the highs are over-emphasized. For example, with a pronounced flute in a quality recording, its sound is overly bright and relatively loud, almost harsh.

I'm getting much more satisfaction from the system compared to when I first set it up a couple of weeks ago, I think due to listener placement experimentation, and perhaps because it is still being broken in. I bought the equipment used from Audiogoners, but it was almost-new, both in appearance, and according to the sellers (who I trust).

I know I am probably not close to maximizing the system's potential, but due to my desire to keep the room the way it is - not dedicating it to 2-channel – AND keeping the girlfriend happy - AND given that I'm almost satisfied with the sound - I just want to try a few more things to get rid of the treble glare and improve the bass.

Perhaps another sin, I’m using stock copper speaker wire and stock XLR interconnects. RCA interconnects are from Outlaw Audio.

Please, oh Masters, forgive my transgressions…

With a good recording without extreme treble emphasis, the system sounds great. Almost brings me to tears at times…

Removing the coffee table improved bass. GAF was low, but Hey…

I'm receiving AcoustiSoft software + measurement mic/preamp next week and will start taking measurements. Will "work" on bass first.

There is a lot of window space on the back wall and the left (long) wall. I've ordered cellular blinds with high sound-absorption ratings. The current blinds are wood. There's not much room for corner bass traps.

There are MANY acoustic influences in the room. Like a smooth-brick fireplace that runs all the way up the (high) back wall at the rear of the half-wall. Also, in front of the fireplace, is the room entrance. Here, there's a small protruding mini-“wall” jutting into the room (just a foot or so) with a rail to step down into the room (it's a sunken living room).

I think this room would be an acoustician's nightmare. I'm surprised the system sounds as good as it does. Maybe because of all the weird angles, reflections, furnishings, etc., it's achieving a good amount of diffusion(?).

I would really appreciate any ideas and products recommendations that I could try in spite of the constraints… I’m somewhat open to the idea of getting rid of the “towers”… or some of the furnishings… or the girlfriend (just kidding)…

But if there are things I could try short of that, I’d sure like to. I have a fairly open mind in terms of budget.

Thanks much in advance for your advice.