A little help maybe? "Muffled" sound above 12th fret

[mezzio]

The other say I changed the strings on my SECU24 to a lighter gauge, and since then have noticed, everything I play above the 12th fret sounds muffled. I thought maybe I was inadvertently palm muting, but that's not the case. I've been trying to practice different styles outside of my comfort zone, and it's hard to do things like hammer on and pull off when the string doesn't sustain at all. If I work the 11th fret and below, I can do what I need to do.

So what would cause something like this to happen? I'd really hate to think it's because I went with lighter gauge strings, I've owned a lot of guitars, and swapped a lot of strings, and never have I had anything like this happen... are PRS and SE guitars picky or might there actually be something wrong?

 

[andy474x]

Could be because your trem "laid down," or your truss rod relaxed a bit. Lighter strings put less tension on the trem springs, and the trem plate could be sitting too low. If it's touching the body, it's too low. It should be 1/16" up, about level with the top. Also check your truss rod, when fretting the first and last fret the neck should be just a bit concave and give you a little bit of space at the 12th fret.

 

[gball]

In agreement about the trem. You'll likely also need to check the truss rod, action (after adjusting the trem) and maybe intonation. I just went to 9.5's from 10's on only of mine and had to do all three.

 

[cwgatti]

Every guitar I ever owned, I had to have her set up when changing string gauge. I would suggest a set up. Then keep an eye on it. I had to do the same thing with a brand new American Standard Tele just this year. It was fretting out, and now the action is a little high. Nature of the beast i think.

 

[mezzio]

Thanks for the replies I would have replied sooner, but ended up sick as hell with some stomach thing right after I posted this, so checking the thread wasn't exactly top priority, lol.

The bridge is good... ever since owning a Floyd Rose back in the day, every guitar since regardless of tremolo type I've always taken measurements before removing the strings, so its sitting with a half of a mm from where it was.

I also tried checking the neck with a feeler gauge pressing different frets from the 12th fret and going up. It seems like what may be causing the muffled sound is the fret immediately after which fret I'm pressing is touching the string. I'm taking the guitar in on Monday to have the nut looked at, so ill have them just do a complete set up since I'm probably gonna be pretty much paying for it anyway, lol.