I've been running one 1000F with bench tested 335 watts in a 0.7 cu ft 3 1/2 inch deep enclosure, behind rear seat in pickup. I was pleasantly surprized by lower than expected roll off point for a shallow sealed 10 inch sub. It starts to roll off slightly around 40-45 hz and rolls off noticably at 35-30. Can't complain at all with the low subbass extension. The efficiency is not 90 SPL probably closer to 86, still quite good for a shallow sub in a small enclosure. This thing doesn't sound like a 12 in a big box, however it produces bass notes acurately and with good definition and depth (except near subsonic frequencies). Sounds good with rap, especially with a litlle bass boost; and really good with metal quick tight and full. I definitely think I got my moneys worth, good shallow 10.