HD600 do have nearly zero subbass... I have heard them and they sound exactly like they measure: http://www.innerfidelity.com/images/SennheiserHD600.pdf
HD650 are a different story... They were significantly more veiled, darker and slower than I expected them to sound.
Basically, you want something at least as good/balanced as HD800 or K712 Pro subbass-wise to be fully satisfied with every sort of music:
Edited by emertxe - 9/29/13 at 8:20am