The player is a Cambridge Audio 640D. I don't know of any bass adjusment it may have.If you've every thumbed through the owners manual on any CA product, you'd probably ask yourself why they even write one..( For owners of the CA 540D dvd player,get your hands on the Oppo 970 owners manual, it's comprehinsive and is exactly the same menu etc,)
Using the Rad Shack SPL meter, The 640d is boasting the volume by as much as +4 db over analog vs. coaxial on the same songs. On kettle drums it will climb to +6 over the coaxial feed. While the dacs in the 990 add an extra clearity to the highs and mids, the 640d emphisize the lower bass regions.Once I add multi channel to the mix, everything evens out analog vs coaxial.Still here though, the 990's dacs give an added clearity to the highs.. I can't figure this one out?
I also tried 5 channel stereo with the rear 2 channels cut to -15, again anolog vs coax yielded no difference in volume.
I do have other questions but will for go asking until I have exasperated my limited knowledge trying to figure them out myself.