A year long upgrade to Schiit Saga, Schiit Vidar, Silverline Preludes matched with a fabulous Volkswoofer leaves just the Marantz CD6004 as a target. That CD has been flawless in operation - built like a tank! But I still feel I am missing some crispness, detail, and sparkle in upper mid range and treble regions. Some audiophile reviews mention this tendency - a low end emphasis with a CD6004. I agree. My system sounds heavier at the bottom than I prefer. With some recording I would even call it muffled. Reading that the source is the key, would anyone have a CD player or DVD/CD player upgrade recommendation that might improve those upper regions?