High displacement drivers in sealed boxes

Goals:
To build several sealed subwoofer cabinets with a couple drivers each that is capable of playing 115dB SPL at 14Hz. This will require goobs of low end EQ boost and I know the ContraBass might be a more cost effective solution, but I believe the bass sound of a sealed box is superior and I am willing to pay extra in search of this. Surprisingly sealed boxes and 14Hz are limited by displacement (Sd * Xmax) and not RMS wattage. Look at the graphs below. The quest for high displacement continues.

Data:
Sealed box calculations and plots for some high displacement drivers.
Maximum thermal and Xmax limited SPL are calculated for a varying frequency.
Note: the SPL thermo curve is also the frequency response of the system.

Aura 1808
Cerwin Vega Stroker 18S
Clarion Thunderdome (Qtc=.707, negative Vb!)
Clarion Thunderdome (Qtc=1.2)
Dynaudio 30W100XL
Earthquake Magma12
Fane Colossus 18 XB
Fane Colossus 24
HSU ASW 1201
JL 18W6
six JL 18W6 (just to show scaling)
McCauley 6174
NHT1259
Reflex PE 295 055 (this is the Dayton HD II)
Tekton KB 18
Tekton KB 21
Ultimate PW1550
Ultimate UWP1880DV

some miscellaneous plots of interesting comparisons
Read some Bass List high displacement driver in sealed box postings

Qtc=.707 critical specs and Xmax limited SPL at specific Hz:

driver	diameter	Xmax	SPL 1W 1m	W RMS	F3 Hz	box size (cu ft.)	14 Hz	20 Hz	30 Hz	40 Hz
Aura_1808	18"	.709"	98	800	89.32	1.53	100.3	106.5	113.5	118.5
Cerwin_Vega_Stroker_18S	18"	.75"	96	1600	114.75	0.49	100.8	107.0	114.0	119.0
Clarion_thunderdome (Qtc=1.2)	32"	.543"	97	300	21.76	53.9	108	114.2	121.2	126.2
Dynaudio_30W100XL	12"	.354"	92	450	38.9	4.12	87.2	93.4	100.5	105.5
Earthquake_magma12	12"	.75"	83.5	400	31.3	4.47	93.7	100.0	107.0	112.0
Fane_Colossus_24	24"	.740"	101	400	22.1	31.12	105.7	111.9	118.9	123.9
HSU_ASW_1201	12"	.551"	91	150	66.15	0.92	91.1	97.3	104.3	109.3
JL_18W6	18"	.5"	88.9	500	36.8	3.77	97.3	103.5	110.5	115.5
six_JL_18W6	18"	.5"	88.9	500	36.8	3.77 * 6	112.8	119.0	126.1	131.1
McCauley_6174	18"	.6"	94	800	41.6	7.79	98.9	105.1	112.1	117.1
NHT1259	12"	.512"	90	150	29.2	4.93	90.5	96.6	103.7	108.9
Reflex_PE_295_055	15"	.45"	97	450	36.3	6.12	93.2	99.4	106.4	111.4
Tekton_KB_18	18"	.748"	89	300	28.3	6.90	100.8	107.0	114.0	119.0
Tekton_KB_21	21"	.866"	92	400	28.1	12.04	104.7	110.9	118.0	123.0
Ultimate_PW1550	18"	.5"	97	210	36.3	6.28	97.3	103.5	110.5	115.5
Ultimate_UWP1880DV	18"	.52"	93	250	36.7	13.82	97.6	103.8	110.9	115.8

Analysis:
My 115dB SPL @ 14Hz goals can be satisfied by:

6 Aura_1808's
3 Clarion_thunderdome's
6 Cerwin_Vega_Stroker_18S's
2 ContraBass boxes
24 Dynaudio_30W100XL's
12 Earthquake_magma12's
3 Fane_Colossus_24's
16 HSU_ASW_1201's
8 JL_18W6
7 McCauley_6174's
18 NHT1259's
13 Reflex_PE_295_055's
6 Tekton_KB_18's
4 Tekton_KB_21's
8 Ultimate_PW1550's
8 Ultimate_UWP1880DV's

Notes:

The parameters and availablity of the Fane_Colossus_24 is questionable.
The Tekton drivers are made in Italy and no longer available in the US. The cost was high at about $1000 a driver!
The NHT1259 and the Reflex_PE_295_055 (Dayton HD II) is looking to be very hard to beat cost wise.
The Cerwin_Vega_Stroker_18S, Aura_1808, HSU_ASW_1201 drivers are not suitable for traditional unassisted sealed alignments.
The Aura 1808 is expensive at $750, it must be because of those neodymium magnets. Check out the Aura 1808 T/S parameters.
The Clarion Thunderdome 32" driver will work much better in an infinite baffle or vented alignment. Check out the thunderdome 32" T/S parameters.
The F3 of a ContraBass is 16Hz at 114dB
The McCauley_6174 is also available with a rubber surround that lasts/wears 3 times better than the foam surround one, the Fs of the McCauley_6174 with the rubber surround is 26Hz.

Check out my quest for bass page.