well i had mine tuned at 38htz with only 14" or port per cube. it sounded great , had a great bandwith but if i were to meter it i would have added more port. pretty much if i had the port right and more power (it was on low power) it would have been louder but decaf on it was awesome even with being tuned in the upper 30s and again low power. if i had anotherone id know what to do with it this time (it was my first 18)