Fret rattling?

[azfryguy]

I am setting up my friends bass and its an Ibanez SRX 300. So its not the best in the world but far from the worse. He has been playing for a couple years now and his main instrument is drums. He is a great player and a great friend so I want to do the best possible jod I can. After I polished the frets cleaned everything and put it all back together I started to set it up like a normally do. I tuned it up put a little bit of bow in the neck (like Jerry Drozd suggested) and use a 32 ruller at the 15th fret to messure and set up the string height. I was playing and all was well until I realised when I play a little bit harder than normal the string I am playing on starts to rattle, not buzz, but rattle. It's a very odd sound and it is only on some frets I.E

E-all of them
A-all of them
D-1,6,7,8,9
G-1,2,3,4,6,11,12

I cannot describe it any better so you will have to work with me here. If anyone has any suggestions please let me know

Thank

[96tbird]

Try new strings. The outer windings can unwind a bit and then slap against the inner core. Bend new strings at right angle before trimming them to lock the winding in place and as you tighten them, make sure the string doesn't twist... let the ball end rotate freely until it settles into its notch. If not, trussrod?