<!--[if gte mso 9]><![endif]--> So now the question regarding the drivers and the maximum sound pressure level they can produce.
The following numbers come from actual measurements done at two meters on a ground plane. They are the Dual Funk Audio sub detailed in this thread:
12 hertz 115.5 db 12.5% distortion
14 hertz 121.5 db 6.5% distortion
20 hertz 127.5 db 7.75% distortion
25 hertz 128 db 7% distortion
32 hertz 130 db 4% distortion
40 hertz 125 3.5% distortion
50 hertz 123.5 7% distortion
63 hertz 126.5 5.6 % distortion
In a room you can get significantly more sound pressure level. Add a minimum of 6 db to each number due to dual boundary reflection. As you drop below 30 hertz you can add 9 to 12 decibels to each number due to room gain and dual boundary reflection.
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