how well a sub plays music has nothing to do with whether its sealed or ported, but everything to do with the quality of design.
How you perceive that quality probably has a lot to do with what you have heard in the past and were convinced sounded good.
Lots of people want a sub that will pound or give lots of slam/impact. As Jay pointed out, that comes from a boost in certain frequencies.
All of Axioms subs sound very good with music because they apply the same design philosophy to their subs as is applied to the speakers: play clean and flat through the designed operating range.
The SVS upped the bar when they released the PB13 and I expect that HSU and ED have followed with their most recent offerings.
