Earphones lose volume a second after I connect them
I have Apple earphones and they were working nice. A few days ago they lost volume and sounds at 50% of how they normally do. I realized that when I connect them to the computer, iPad or iPhone they sound at it's 100% for a second and then the volume abruptly goes down.
MacBook Pro (Retina, 13-inch, Late 2013), OS X Yosemite (10.10.4)