Hey guys, new girl here... So love my Mazda but had an issue that started today... The bose stereo, if the mp3 player or phone is plugged into the audio jack it sounds like crap now... Hiss, less bass, things like that... Another cord same thing. Put on the radio and we have to turn it up louder to hear it and the sound quality is diminished also...any ideas?

 

Sounds like your bose amplifier is dying.

 

I would start by checking the connections on the headunit. Might be a loose connection causing the problems. I would suspect it's between the headunit and the amplifier.