Absorbtion?

A friend of mine was also battling his L-shaped living/listening room. Currently he is putting his system in the corner diagonally toward the other corner of the L with good results. Maybe you can give that a try if space permits. Another possibility is getting a screen or some sort of room divider to corner off your listening area, again, if space permits.
BTW, play with different cables if you can. I have MIT cables myself and they are a bit on the warm side, which is great for my otherwise over-bright system, but maybe a little too warm for systems with more neutral-sounding equipments.

Good luck and happy Listening.

Something is suspicious here as the Cardas placement's whole goal in life is to reduce the effect of the room on the sound.

Perhaps you are too far off-axis. You might try some toe-in and see what happens.

Also, some speakers work well in a 'nearfield' setup and some don't. I don't know about your speakers specifically but you might look for some opinions there. How far away from the speakers do you sit in the dealer's setup?

HTH.

While this may be heresy to some, I've found that a slightly asymmetric setup works best in an L-shaped room. The end result is based on a LOT of listening, as well as a great deal of computer simulation analysis.

In my case the right speaker (the one near a side wall) is a few inches forward of the left one. The speakers are also positioned so that the inside corner of the "L" is near the point of first reflection of the left speaker to help balance the overall presentation.

Now someone will tell me how horrible a sound this must create and burst my bubble. And after all that analysis...

Thanks everyone so far. The sound does get more harmonic in the perfect nearfield but highs are still subdued. I sit a few feet behind the ideal nearfield cause of room asthestics. Has to be the room, this is the 2nd setup and 3rd pair of speakers used. I almost feel like stripping the room, padding and rug (hardwood under) also and starting over in a live room. Also have a smaller room that is 11x16x8 closed in rectangle w/hardwood floors and sheetrock walls/ceiling. Not bad measurments to start with except the 16long and 8ft height (multibles are said not to be ideal). Dealer tells me this room is too small. Is this room too small for the Aerial 10t with 300W Classe ca300? This is a live room that can easily be set up using the Cardas Method and perfect nearfield triangle. This room can also be treated anyway i want. One long wall has a cement firewall behind it and easy to run a dedicated 20amp line or 2. I really don't believe everything my dealer tries to tell me. I know more than most of the floorpeople, but so does everyone else! Give me your blessings that the 11x16x8 room is not to small. I'll go for it, lot of work!! Spks will end up 36.432 from side walls and 59.136 from center of woofer to woofer (pretty close together for 10Ts) and 59.004 from backwall and 59.004 to listening position with 73.992 left behind listening position. Can any rocket scientist evaluate this? Will it work? I know try it and see, but a huge choir for me if the room is too small. Thanks Mike

IMO your room is not too small. There are other issues at work here, synergy being the primary I believe.
Not sure where you're going with the 'glass' question but certainly it reflects. I had a pair of split glass doors on my heavy wooden component rack (which I very rarely closed anyway). One day the cats were roughhousing & banged hard into one open glass door, stripping out a hinge woodscrew. In the process of effecting a repair, I removed both doors from the rack. The rig was playing & as I was walking around the house I noticed an improvement (a reduction of midrange glare, which I had been trying to figure out for some time). Following some brief critical listening, we decided that those glass doors were never again going to be installed.