i would prefer Sheffield Lab CD, various songs in the CD eg. Jazz, Classical, Bass, Ochestra, Instrumental, Acoustic, Unplugged and so on. Usually what i do (sound tuning) for my friend is using this Sheffield Lab CD and thereafter their favourite CDs for fine tuning.
Why Sheffield Lab?
It was recorded proffesional in Sheffield Lab and from diff diff sound engineer. Also included with the CD Label, the explanation of what you are expacting from each song track. So try this ONE CD which cost about RM45 (8 years ago) and feel the deep bass around 25 - 35 Hz. Probably you can just feel without hearing :D
Happy ICE