BL .. have had a 15 and an 18 tuned in mid 40s as well as tuned in low 30s.. got loud in any enclosure with 1500 watts daily was very durable and sound pretty good for a SPL oriented woofer.. be sure to get it with FW coild and coolin option.. do not get extreme lead as will make wierd sounds and really isnt necessary.. also 3 of my teamates have has AQ HDC3.. they are a loud woofer with lots of mechanical noise and dont sound very good .. also had issues with spider packs coming apart.. and auqio Q is much more difficult to take apart for re coneing..