Most of the time, what makes a “bad” singer is the terrible pitch accuracy, which actually has to do with your brain. Most everyone is physically capable of singing well when you look at their vocal chords and the “natural” equipment you use to produce a tune. The problem lies in the fact that people who can’t carry a tune or pitch accurately do so, because their brain doesn’t have the ability to compare its output with its target and then adjust to match. This is why sometimes no matter how many times you listen to a song and then try to reproduce it, you just can’t match the same sound. Even if you can hear yourself making the wrong sound, people whose brains can’t make the correction just insist on making the error. Unfortunately, you can’t make your brain do something that it doesn’t understand how to or just refuses to do.