*daylia*, The problem with many tuners is that they are only accurate within some published margin of error. If you read the sheet that comes with one, the manufacturer usually includes the accuracy with words like "accurate within 3 cents" or "+ or - .5 cents."

As I recall, the popular Intellitouch tuners that clip onto the headstock of a guitar are accurate to within 3 cents. It may be 2 cents but this means that your E string could be 2 or 3 cents high and still register as right in tune. At the same time, your B string could be 2 or 3 cents low and still register as right in tune. A difference of 4 to 6 cents between those strings will sound dreadful to most listeners.

There is a new line of PacRim tuners sold under various brands including Meisel and Intelli that claims accuracy of + or - 0.5 cents. This tuner also has a simulated needle display instead of lights or arrows.

The wonders of technology notwithstanding, the best and quickest way to tune an instrument is to learn to tune by ear as *daylia* describes. It's the ear that must be pleased, not some physicist or engineer. Electronic tuners are best used to accurately tune just one string of your instrument then tune the instrument to that by ear.

      - Mark