Vandersteen 3A Signatures with 2 dB difference between L and R Speakers

make sure they is in phase

a slightly less tight connection can effect signal strength/volume. either end of speaker wires. either end of interconnect.

verify all tight, measure, _____?

switch the speakers themselves. measure again ___? if difference moved with the speaker, it's the speaker. If difference remained as it was, it's the equipment/chain.

Another reason to have remote balance control. I won't live without one of these. You need the remote control, it won't work without it.

https://www.ebay.com/itm/274870895426?mkevt=1&mkcid=1&mkrid=711-53200-19255-0&campid=533...

 a few are available now, sometimes none, 

https://www.hifishark.com/search?q=chase+rlc-1

Thanks everybody for your responses.  I have been trying varying the cables between various components and no difference.  The last one I will try are the speaker cables to amp connections (I'm bi-amping so there are 2 pairs per side).  If there is still no difference it is definitely the speakers.

There is a return period for them, but want to avoid it unless it's something that is likely to deteriorate over time.  I'd like to enjoy these speakers for the next 10-20 years time frame at least.

Is there an opening on one side of the room that is not on the other side like a doorway?  Until you put them side by side in the center of your placement area you won't be able to get any room differences out of the equation. 

verify tight and in phase and level controls on speakers set same.
swap at amp end only L to R, both low and hi frequency bi wire,  IF level change to opposite problem, it’s amp or upstream.

2db is way out of spec if speaker in same acoustic space w same input.