What Removes the Vocals When an Audio Jack is Partially Unplugged?
There are two quite common, extremely annoying issues we’ve all experienced with wired audio jacks. The more maddening one is when the wires start crapping out and one of the speakers or headphones drops audio, requiring constant wiggling of the wires to resuscitate the dropped audio. A similar, though more fixable problem is when, suddenly, the vocals drop out of a song, but the majority of the audio is left intact. The fix for the first issue is to usually get a new set of headphones, and treat the wires a little better. The fix for the second issue is generally to shove the jack farther into the receiver. Easy peasy, but if the jack was unplugged, why did any sound play at all, and how come the issue always seems to target vocals, rather than another track?
A question most of us has pondered, but don’t necessarily have much experience with audio or electronics to answer ourselves. Stack Exchange user editor put pride aside, braved the knowledgeable community, and asked what some people with a certain level of experience would consider a fairly common knowledge question. As always, the community received the question well, and provided an answer that is simple enough.
Stereo headphones form a circuit of a common ground, a left amplifier output and headphone, and a right amplifier output and headphone. When the audio jack slightly slips out of the hole, the ground contact is usually broken, but the rest of the contacts are still being made. Vocals tend to be put into the “center” of a stereo image, which is what is lost when the ground contact is broken. However, if the ground contact is broken but the audio jack is still plugged in enough, the left and right channels are still active, so any audio that was different enough to be kept on the different channels can still make it through. The vocals, or other audio that is mixed equally into both channels (and thus, in the “center”), fade away or mute entirely, essentially because the only connections being made are the separate left and right channels.
Luckily for anyone that has a pair of headphones, the problem is easily remedied by making sure the jack is plugged in securely. If you experience the wire-wiggle issue, well, it’s time to get a new pair of headphones and make sure you don’t crumple them up into your pocket under your phone all the time.
(via Stack Exchange)