Also, something is not right with your room dimensions. Either one dimension is not correct or the total volume is not correct. If the dimensions are OK then your room is about 2200 cu ft and that's a large room for a single L12. A ported subwoofer like the LV12R will do better or even dual L12s. If room volume is correct (assuming one of the room dimensions is not), then follow what Alan P. is recommending.
Enrico Castagnetti @ Rythmik Audio
Media Room: Ascend Acoustics Sierra Towers w/ RAAL, Horizon w/ RAAL & Sierra 2s | Rythmik F12SE (x2) | Emotiva XMC-1 | Emotiva XPA-3 & XPA-200 | Oppo 105D | Bluesound Node 2 | Sony HW40ES |
Desktop: Dynaudio BM5 mkIII | Rythmik L22 | Apogee Quartet | 27" iMac|
Bedroom: B&W 685 S2 | Rythmik LVX12 | Marantz NR1606 | Emotiva XPA-200 Gen 2 | Samsung UN50JU6500 |