Found a fix for this last night, as I was equally irritated by the level of hiss in my Sennheiser in-ear heaphones...
Just go into Settings > Sound > Media Audio Effects > Wired Stereo Devices and DISABLE AUDIO EFFECTS.
My Razr Maxx came stock with this ON, and it was causing a ton of background hiss when playing any type of audio. Turning it off got rid of 80% of the hiss and brought it back down to an acceptable level.
Just go into Settings > Sound > Media Audio Effects > Wired Stereo Devices and DISABLE AUDIO EFFECTS.
My Razr Maxx came stock with this ON, and it was causing a ton of background hiss when playing any type of audio. Turning it off got rid of 80% of the hiss and brought it back down to an acceptable level.
