I'm just going to throw some stuff out there, it might be useful it might not.
With a single 12" driver you are usually limited to 110-113db max. With the speaker in the corner you should be able to get an extra 9-18db. At 12ft it should take about 800w to generate a 106db signal at your seat without
room or boundary gain with a 89 db 1w/1m driver. The Inverse Square Law teaches us that for every doubling of the distance from the sound source in a free field situation, the sound intensity will diminish by 6 decibels.
Here is a tone generator, please use the sine waves only sine wave generator