You have not sent me a link to your current sub. If you can send me a link or exact details of your current sub I can render an opinion. Just because a driver is larger does not mean it has to be a better sub, in equivalent applications.
You still have not sent me a link to your current driver and box. I can't find any details of that 12 inch driver you quoted. However here is another 12 in Dayton sub I modeled previously. There are no xmax problems and the F3 is 17 Hz. The spl is a little lower than yours above 50 Hz, 111db versus 114db. However it maintains that spl to 20 Hz, where your 15 drops to 102 db.
Name: Dayton TIT320C-12
Type: Standard one-way driver
Company: Dayton
No. of Drivers = 1
Fs = 22.2 Hz
Qms = 6.12
Vas = 73.91 liters
Cms = 0.0977 mm/N
Mms = 525.8 g
Rms = 11.98 kg/s
Xmax = 18.7 mm
Xmech = 28.05 mm
P-Dia = 304.8 mm
Sd = 729.7 sq.cm
P-Vd = 1.364 liters
Qes = 0.47
Re = 3.07 ohms
Le = 3.17 mH
Z = 4 ohms
BL = 21.89 Tm
Pe = 500 watts
Qts = 0.44
no = 0.166 %
1-W SPL = 84.35 dB
2.83-V SPL = 88.6 dB
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Box Properties
Name:
Type: Vented Box
Shape: Prism, square (optimum)
Vb = 4.303 cu.ft
Fb = 17.28 Hz
QL = 6.283
F3 = 18.18 Hz
Fill = minimal
No. of Vents = 2
Vent shape = round
Vent ends = two flared
Dv = 3 in
Lv = 28.27 in
