On my phone, the headphone jack is not working right. I use my phone to play music mostly, but recently, it went weird. I can hear every instrument fine, but the voice of the singer I cannot hear for the most part. I have wanted to fix this for a while, but I'm not sure how. Now, I am aware that this might be the file, as I download the song, and then pull it from my computer to my phone with the cord it uses to charge.
It is a problem with all songs, if I take the headphones out they play normally, with vocals. With headphones, the lyrics get screwed up.
There may be dirt or something in the headphone jack, or your headphones might be damaged. Try a different pair of headphones and see if they work, if they do then it's most likely your headphones, if they don't then look up ways to clean the headphone jack.
It's probably the headphones if otherwise the lyrics are ok. Have you tried to use them for another device? They should screw up sounds even for your computer or anything else; if so, you can either try to clean them or change/fix, because headphones tend often to break. And a spare pair is always a good thing to have.
Try other headphones on and check whether they are working. If other headphones are working then the fault may be in the original headphones. If its the same problem with other headphones then there's a problem with with phone.