Wilson Audio Sasha sound imbalance

My experience has been that for whatever reasons the channels may have an imbalance. Swapping sides is the first thing I do, then I adjust positions (loudspeakers and me) until it is optimized. Loudspeakers often have different outputs, sometimes substantial, often sold in matched pairs.   

Wilsons won’t come out of the factory mismatched, I promise you that. If the resistors don’t get it done, call Wilson and see what they recommend. Also, make sure your binding posts are tight!

I replaced the resistors, and the imbalance exist.
Its really in the vocal area more then anywhere else.
Eg: The centre image for instruments such as drums comes in the centre but vocals seem a tad off to the right.

Anything I can do to test the drivers?

1. Try swapping the speaker cables only.
2. Measure the exact distance from each speaker to your head where it would be when you're seated.
3. Get yourself an SPL meter and check both speakers are matched by measuring the same frequency for each speaker individually.
4. See if you can find a copy of 'Best of CHESKY' Classics & Jazz and Audiophile Test Disc - Volume 3. They have some microphone techniques on that CD that should help with locating center vocals. Or something similar to this type of CD. 

Call it an audio band aid if you must, but I miss the days when equipment had balance and tone controls.

I did purchase a schitt lokius a month ago and could not be more pleased to be able to make minor adjustments.  I have soft dome scanspeak tweeters and I find adding just a touch of emphasis is the cat’s meow.  So little, but tuned just to my preference.

But no way to make any adjustments to left or right channels independently.