If the tone of your note sounds buzzy or kind of dull and plunky, it could be that not enough pressure is being applied with your fingertip. This could be due to the fact that your fingers are still getting used to the guitar, and are not yet strong enough to hold down steady pressure.
But it could also be because your fingernails are a little too long, impeding your ability to get good solid pressure against the fingerboard. Or, it could be that your guitar's action is too high, meaning the strings are suspended too high off the fingerboard and make it extra difficult to press them down adequately.
Experiment with fixing the tone of your plunky note by adjusting your pressure. If you figure out what the problem was, be sure to make a note of it, and let your hand memorize how you went about fixing it.Â
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