op the hg 15s are not going to be a good match a 15 inch driver is going to be slow
nor do the ls60s go as low as a pair of subs try a pair of kef kc 62s or kf 92s for a superior bass
if you are looking for an upgrade te kef reference 3s wll match much better with your subs
Dave and troy
audio intellect nj
kef dealers