"What I mean is the song is the song (the digital data), from a digital standpoint unless it get modified in the digital realm,"
It does get modified in the digital realm by xmos chip or similar when converting the streaming signal to something that can be transmitted via cable which sounds like optical in your case. Optical typically has the lowest resolution/sq compared to usb AES or I2S. I would try a usb connection if the hardware has that option and as others have said, seems like a setting somewhere could be the main culprit....