I did a little experiment today, while tuning my guitar.. I tuned the whole guitar with the tuner but my tuner somehow stopped working while I reached the low e string.. [I tune from high e to low e].. so I tuned the low e by my ear... and that thing sounded heavy .. I recorded it. And played a few songs.. but a little later when my tuner started working again.. I came to know that the low e string was not in perfect tune.. it was a bit down.. so I tuned it back up... although now it was in perfect tune, but it didn't sounded heavy like before.