Just to lighten up the issue of 15" sub is 'slow' or 10" sub is 'faster' etc.
read up here : http://www.adireaudio.com/Files/TechPapers/WooferSpeed.pdf
p/s: heavy woofers = woofer with high moving mass i.e those 15" or 18" or maybe even 12"
light woofers = woofer with smaller moving mass i.e can be 10" or 8" or even 12" depends on what it is compared to.
read up here : http://www.adireaudio.com/Files/TechPapers/WooferSpeed.pdf
p/s: heavy woofers = woofer with high moving mass i.e those 15" or 18" or maybe even 12"
light woofers = woofer with smaller moving mass i.e can be 10" or 8" or even 12" depends on what it is compared to.