Dead Strings on MIM Precision

[maximumcaz]

Hi all-

This is my first post on here and I'm looking for some potential advice for fixing my bass.

I recently bought a 2003 MIM Fender Mark Hoppus signature Precision Bass used off of craigslist. Soon after buying it, I adjusted the intonation and saddles myself to lower the action. This resulted in a small amount of fret buzz on the 2nd-5th frets which was remedied by a guitar tech recently who loosened the truss rod to add a little relief. Now everything seemed to be perfect... no buzzing whatsoever and my action is about 4mm at the 12th fret which feels perfect for me.

However, I've only used the bass once live since the neck was adjusted and I noticed now that the E and A strings sound ULTRA dead. These strings have only been on for about a week and a half. I even re-wound the E & A and still sounds bad especially acoustically.

Does anyone know what the problem could be here? Perhaps the nut? Or does my neck have too much relief now?

One other thing to note is that this Mark Hoppus signature bass has the strings going through the back of the body, not the saddle... could this be a factor as well?

Thanks!