One of the high E strings is muted on my 12 string .

[AJ6stringsting]

I picked up Fender 12 string guitar, lowered the string height , using the truss rod.

My first string of my high E is being slightly muted and not vibrating as well as second high E.

I inspected the frets to see if the string was fretting out on the frets and it wasn't.

When I looked at the bridge, it seems like the angle from the bridge pin is linear, compared to the others that are angled.

Could this be the cause of the string not vibrating / resonating properly ?

[Grant Harding]

Yes - that's really common. I'm assuming it's a used guitar and that the bridge saddle has been lowered multiple times so there's almost no break angle on that string over the saddle. A pic would help the diagnosis.

It might need a neck reset, but you can probably cut a ramp behind the saddle to reinstate the break angle. All of my older acoustics have been modified like this, so each string has really solid down pressure on the saddle.

 

Also - did you check the relief before cranking the truss rod? That's for neck shape, not string height.

[DeepEnd]

First, Setup 101 says you don't use the truss rod to adjust action. It's solely to adjust relief. On an acoustic you have to do things the hard way and sand down the saddle from the bottom. Second, yes, you need a certain amount of "break angle." Some folks say 45° or so, most guitars have on the order of 30° and they're fine. IMHO, 15° is often adequate. But as you've noted, on a 12-string the "break angle" can be much less for the octave strings, sometimes only a few degrees. One solution is to raise the saddle; the other is to "ramp" the bridge, which you can do if you're handy, using needle files or a Dremel. Here's an explanation from Frank Ford at Frets.com: http://www.frets.com/FretsPages/Luthier/Technique/Guitar/Bridges/StringRamps/stringramp.html. Before you do anything else though, make sure the guitar is properly humidified, then adjust the truss rod properly and either live with the result or sand down the saddle. Put a capo behind the first fret and hold the low E down at the neck/body joint, probably the 14th fret. Next, slide a feeler gauge between the top of the 7th fret and the string. There should be a gap of .010" or less. If the gap is larger, tighten (turn clockwise) the truss rod nut a bit, say 1/8 turn, and measure again. If the gap is significantly smaller, loosen the truss rod nut (turn it counter-clockwise) a small amount and measure again. Repeat as needed. Once you have that done, then start working on the action.

[Freeman Keller]

Pretty hard to diagnose without some more information. Did it sound OK before you adjusted the truss rod? Can you tune each E string to pitch open? Can you play each string at each fret and get a clean note all the way up the neck? If not, is it one fret, several, maybe at the body joint. What kind of shape are the frets in? Have you measured the action, relief and nut clearances both before and after you adjusted the truss rod? Have you checked the neck angle? How much saddle is sticking out of the bridge (particularly the high E strings but how about all of them)? Fender has done 12 strings with the first string close to the saddle and farther away, which one do you have? Is this a new guitar? This doesn't happen to have a Bridge Doctor or those funky bridge pins with the holes in the head for the strings? If you press down hard on the the string from the saddle to the pin does it sound OK? Is there any separation of the bridge from the top? Have you looked inside to make sure there aren't any loose braces and that the string balls are seated against the bridge plate.

 

A picture of that bridge would help. Edit to add, I would like to know its thickness too.