Tune it higher unless it's already high , Bonhams bass heads were both quite tight apparently I tried it on mine and it worked for me . Another thing is to not bury the beater in the head but let it come back off the head every beat to let it ring more .
Weak to you from the driver's seat, or weak to your audience?
What heads do you have on there?
Mic'ed or unmic'ed?
I had a Gretsch Catalina Jazz kit with an 18" kick and it sounded amazingly full with an Evans EMAD and the stock resonant (front) head, which was basically a coated PS3. No muffling at all, tuned a tiny bit higher than you would expect for an small drum. I also had an Audix D6 on a Kelly Shu permanently mounted inside the drum and man did that sound nice through the PA.