Hdc3.1 single 15 enclosure

[Cypress5000]

Definitely a newb guys.. Hdc3.1 15 2dvc tuned at 34.85hz and 3.78ft³ running off a skar rp-2000.1d I couldn't find exact recommendations for the box size so I went with the ones on soundqubed website for the newer model. My question.. is the box big enough/ or too big? Is that a decent tune for the sub? I expected alot out of the setup and frankly I'm a bit disappointed with it. Granted I havent sealed the box yet and it has some leaks but it seems like its lacking in areas. Coming from 2 12in kickers it hit the lows good but the fast repetition of metal and rock just isn't there. Is this because of the cone size difference? Or box/amplifier tune?