Hi, just wanted to see if anyone had any thoughts on an issue I am having with my B string. I have a Taylor 414CE, in case it is relevant. After the guitar is fully tuned, when I play a D chord, I noticed that the B string is slightly sharp. I threw my Snark tuner on just to be sure, and sure enough it is. It is in tune when the string is not pressed down, but goes very slightly sharp when pressed down at the third fret.
Any thoughts?
Chris
One of a few things…
Most likely your pressing too hard OR the nut is cut too high and it needs more force than it should
It also could be an intonation issue but that’s less likely
Is this recent or has it always done it?
If it’s recent it could be that maybe it’s a movement in your neck due to change in the weather and or use of central heating. It’s quite normal for this to happen unless you either stabilise conditions where your guitar is stored and played. If the weather is cold and you’re using central heating unless you humidify your guitar it will start to dry out and the wood will move, this can be destructive if not managed correctly. It could also happen if you store your guitar in a cold room and bring it into a warm room to play it.
Either way look into using a humidifier either in your guitar bag if that’s where you store it or in the room where it’s stored. For the in bag/case type you should be able to get one from Taylor, Amazon, Music Store etc.
Check the pin holding the string into the bridge is still snug, this was causing me to have one string going immediately out of tune a while ago
It doesn’t sound from his description that the string itself is going out of tune. The open string is still in tune, but when you play the third fret on the B string that is out of tune.
I just found this statement on a blog that may be of interest.
The standard method of fret spacing is based on the scale length of the instrument. The frequency of the vibrating string is based on the scale length and is further affected by string tension and string weight. The height of the string also has impact. The higher the action, the greater the string tension must be increased and thus the more sharp the string goes as it is fretted. While most people think of action as being all about playability, it also has a significant impact on tuning accuracy when fretting a note.
So the first thing to check would be the action on the guitar.
A good exercise is to start fretting the note while looking at your tuner. Find just the right pressure for the note to be in tune (which should just be when it starts to sound clearly) then see how much more pressure it takes to go sharp. Higher frets make it easier to push too hard and pull a note sharp.
I see two camps forming in this thread. One where it is a guitar problem and the other a player issue. I tend to blame operator error when I can, humans are like that. But I certainly could be wrong.
This response is in the camp of the guitar having the problem. 
just a couple easy checks I haven’t seen recommended:
It’s probably one of these things like Rob says. Take the guitar to a luthier for a setup so they can check it and lower the nut slot if need be.
It could be a change in neck relief too etc as others have said but I would think that less likely esp if its done this from new
Thanks Rob, I’ll go back and check my technique, as well as the guitar.
Sounds good, thank you.
I honestly don’t know how long it’s been happening. I’ve only lately been getting back to the guitar and I noticed it. I’ve been keeping it humidified in the case, since it is quite cool in the office in the winter. I’ve never had a problem keeping it in a good humidified environment or humidified with the Humidipaks from D’Addario.
All is snug.
Once I touch it hard enough making the D chord to get it clear it is in tune, any harder it goes slightly sharp. I just pulled a tuner app on my iPhone that is a little more detailed rather than use the Snark. I see what you mean… If I used my second finger on the B string third fret, it does not go sharp. When I use my third finger like I would in the D chord, it goes sharp. I must be more confident with my second finger and not push as hard. Maybe there is still a guitar adjustment needed, I don’t know. But there is certainly something I need to practice. Thank you.
Thanks for the help on the tech side. I’ve been wanting to go over those anyway, and have no idea what’s the proper tension. Regarding the tuning pegs, how tight should they be?
I think I’ll do that.
not sure what you mean here. string tension is proper when the string is in tune - but I suspect you mean something else.
Tight enough to stay in place with the string tightened. basically, I use a tool that is about the diameter of a full-sized screwdriver handle and make it firm, but not as tight as I could. Think about the threads on the nut and avoid stripping those with too much tightening. I only needed to tighten mine twice - as the guitar got used to my climate. I have needed to tighten on two guitars, so it seems to be a common thing. On a third guitar, I knew to tighten on day 1, and haven’t needed to do again.
Thanks, sequences. The tension I was talking about was the tension on the nut, but I obviously have no idea what I’m talking about, so let’s just leave it with your advice. 