i have an ibanez GU30 tuner, just wondering what is that 440Hz do? it is adjustable, u can dial from 435 - 445 Hz, what is that for? i misplaced the manual! kindly enlighten me.
440hz is what is called 'concert A tuning', its the hertz at which a perfect A vibrates. (This all has to do with sound stuff etc.)

I wouldn't really see why anyone would want to make it 441hz or anything, and on my LU20 theres already a drop tuning function which shows if its going to Eb etc. So, my advice is to keep it at 440.