I know I'm possibly opening a can of worms here but I have to say what I think on this subject. Because I find it ridiculous that there are people attaching various types of heavy metal plates on their guitars and expecting the guitar to have a longer sustain because of it. So the question is, how does mass affect vibrational frequency? Any object that can vibrate is capable of creating a tone. Two factors determine the frequency of the vibration: the Mass of the object and it's tension. As the Mass is increased, the frequency and the pitch decreases. For example, men in general have more mass in their vocal folds than women and therefore have lower voices.