Why cant my subs get low b very well?

so to start off i have a big variety of subs due to good deals good brand etc, i have a kicker comp vr brand new in a ported box 1.5 cubic feet i beleive, a 10 inch orion cobalt (first sub i ever had) thats in the prefab box right from orion, and last i built a sealed box 1.5 cubic feet for my rockford fosgate p1. my friend has 3 10 inch rockford fosgate p3's in a fairly large sealed box ( deeper then usual box) and it hits lows like no other. my high and mids are about the same but the lows are straight up terrible. i have a 1000 watt 15 year old kenwood amp thats 2 ohm, would this be the problem? my friend also has a rockford fosgate amp i believe its 2500 watt max brand new so would buying a new amp maybe solve why it cant get lows like it could?