Feedback needed, 6x JBL CS-1214

Hello there! I am brand new in this forum and I need some feedback on my DIY plans to upgrade my system. First some background.

Location: Build is for Cyprus, Europe. Current location UK
Space: >2,000 sq feet open plan space
Speakers: Wharfedale Diamonds 10.CM, 10.5, 10.1, 10.DFS, Subwoofer: Wharfedale SW150
Source: Windows 8.1 with EqAPO and HDMI
AVRs:
-Sony STR-DN 840 7.2 - Surround Mode Output Power: 150 W per channel (6 ohms, 1 kHz, THD 0.9%)
-Sony STR-DH 820 7.2 - Surround Mode Output Power: 140 W per channel (8 ohms, 1 kHz, THD 10%)


Ok then. In order to save as much money as possible and based on my current system I came up with the following plan with which I need some help as I am not sure it is correct. I am looking for low end frequencies <=20hz as I am mainly enjoying bass heavy movies. I normally don't listen to reference levels.

My choice of drivers to is very limited as I live in the UK and prefer to buy locally to save on taxes and delivery. JBL GT5s and Infinity 1260w are nowhere to be found so my current choice is pretty much the JBL CS-1214.

The plan is to go with 4 or 6 drivers in individually sealed boxes of 1.5 ft3 which can be placed anywhere the listening area. and reach frequencies below 20hz. As these drivers need a lot of space to make vented and I also have a second 7.2 AVR in hand I thought sealed enclosures would be best as these drivers seem to reach xmax 12mm at around 30w after eq in WinISD. These seem to model quite nicely but I am not sure if my calculations are correct or if my plan to use the second avr as a sub amp is a good one. The system will look something like this:

Laptop -> EQed PCM signal to Sony STR-DN 840 7.2 AVR -> LFE signal to secondary Sony STR-DH 820 7.2 AVR -> Output full range to 7 channel mono/stereo. One sub per channel at 4 ohms or 2 subs per channel at 8 ohms (not sure if the second amp can handle 4 ohms?).

The following modelings are for 1x JBL CS-1214 with 30W power and 6x with 180W power.

113db seem too good to be true for the budget. If there are any flaws with the plan I would really like to know before I purchase the drivers! Is the plan and choice of drivers correct and suitable for my space and listening levels? Thank you! :smile: