I have an acoustic guitar called "Jasmine" by Takamine.

Background info as follows:

Purchased in December.

At the end of March I was told I should restring my guitar. Being a complete newbie to guitars, I asked the clerk at the store for some light strings for a standard acoustic guitar.

Well the strings provided were "Lay's SIT Strings" Pro lightt RL-1150
.011 .014 .022 .030 .036 .050

Upon restringing with the help of someone who has been playing for 30 years, my 6th string had a strong RATTLE.

We tried various solutions none worked.

*While I was away in another room this guy decided to turn the "bolt? Peg? or tunning rod?" inside the neck of my guitar. I don't know how much they turned it, or if he turned it back.* - Fyi he had told me before we restrung that he has never messed with that aspect of the guitar, in all his years of playing. He told me never to mess with it.

In the end the problem did not go away.

I went out the next week and bought larger strings.

Martin Acoustic SP light .012-.054.

Conclusion- The string rattle is 90% gone. Huge Difference! Although I am left with a new issue.

When I practice I can hear a wierd oscillation that I have never heard before.
I think the first and second string are causing this. More the first though. You can play a G chord and upon the hitting of the last string the high pitch oscillation comes in. If I had to describe the sound it would be similar to running your finger around the lid of a wine glass to make it "sing".

Help please! How do I get rid of that noise? Is it because the guy messed with the tuning peg?

Thank you,

That thing is called a truss rod.

I would take it to someone to have the intonation checked.
your first rattle was most likely because of the strings.

.011 .014 .022 .030 .036 .050

is the string guage for "custom light" strings. not Light.

the martin SPs that you bought are light, and probably more suited to the guitar. When you put lighter strings on a guitar, the action(height of the string from the fretboard) goes down.

for your future reference, the rod that is inside of your guitar neck is called the truss rod.

as for the new sound that you're hearing... i have no idea. my guess is that it SHOULDNT be the source of the noise. but of course, since i cannot see and try your guitar, i cant be sure of anything.

hope that helps you somehow.
That weird oscillation noise is exactly what I'm also hearing on my Seagull S6. For me the high pitch vibrating noise comes from my B string. When the string is strum or played somewhat hard, the more noticeable the noise. I'm planning to take my guitar in for some expert tunning soon though.
Thanks Captivate and for the info. It helps a bit. Guess I should go check with someone on it.