150db

hi, right now i have a very desent build, moderate experiance and knowledge. current setup for reference i guess: 2012 ford focus hatch back, 1x dd audio 715d2, dd audio cc 6,5" set, soundcubed 3000.1, dls ca-p44 (4x 100w @4 ohms), stetsom dsp. not sure how much db im pushing but to state...

here's the deal. i have a FI Q 18 in about 5 cubes sealed in my scion tc. running off of a Cadence Dakota 2400 maxx...1200 rms @ 1 ohm amp. Today we metered it and I got about 138.9 dbs...which isnt horrible but definitely isnt good. I want to get to around 150dbs. Someone suggest a bass...