Martin Logan ESL X

Have you had other speakers in the room that worked well?  It could be a room issue that you can fix, although not cheaply, with room treatments.

If it isn't the room, you could have a problem with low output from the electrostats causing you to have to turn it up too much.  Very seldom is too much bass a complaint with ML.  Check that the cables and jumpers are all tight so that you are getting good signal to the electrostats.  

Otherwise experiment with room placement.  

Take them out of the room and see if you have the same problem.  If you do, then there is a problem with the electrostats.

Have you pulled them out at least 3 feet from the wall?

The GIK 4” bass traps will tame the bass. But before you buy anything just pull the speakers out into the room about 2 -3ft at least from the back wall and at least as much from the side walls. That’s a free and easy way to manage boomy bass. And check tone controls on your receiver/integrated. You may have the bass turned up…worth double checking that!