off axis or tilted speaker placement ?

Hi,

I have a long and narrow L shaped room in the basement where I put my system (30'x 12' x 7'). Played numerous ways of placement but still not happy as there is definitely some kind of room mode comes into play, e.g., some notes in piano solo works just does not sounds right, and imaging is not quite good.

My system: Harbeth Compact 7ES3, Exposure 2010s, SB3 and a Tubemagic D1 DAC. Here is what I tried so far and none works:

1. speaker against short wall with 5 feet to the back wall and 3 feet to the side;
2. pull out speaker further 7 feet even 10 feet
3. put speaker against long wall but since I only have 12', it is quite awkward as my chair is almost backup to the wall.
4. toe in vs no toe in.

Finally last night I decide to try the following: speakers against short wall but about 8/9 feet away, and instead of firing it straight down the L room, I tilt both such that the center of two speakers and listening position forms a line that is not parallel to the long wall but tiled at a slight angle. This seems to improve the room mode and also imaging.

Wonder if this makes sense. Any other suggestions to try ?

Thanks