p:=Sd*Xmax*f^2*pi*rho0/(r*sqrt(2)) where p=sound pressure in Pa, Sd=eqv. piston area in m2, Xmax=max peak excursion in m, f=frequency in Hz, rho0=1.2kg/m3, r=speaker-to-mic distance in m. The sound pressure p can be converted to sound pressure level Lp=20*log10(p/pref) So with Sd=5000 mm2 Xmax=10 mm f=30Hz r=1 p=0.05*0.01*30^2*3.14*1.2/(1*1.41)=1.2 Pa Lp = 20*log10(1.2/0.00002)=95.56 dB

Piston Diameter in m

Speed of sound m/s

Distance to measurement in meters

one-way (+ or - not total) in m

Air mass in Kg/m^3

reference pressure in Pascals

Listening distance (1m)

frequency

For now, ignore the Sd above since piston is not round.Assume each PCB/piston is 100x550mm and there are 2 pistons in a Ripole config.

This Sd is roughly equivalent to two Peerless 12" Woofers.

Volume flow in m^3/sec for Ripole (two Sd halves) with Xmax of +/- 7mm.

dB

Xmax1 is the distance a piston SD is moving at a given SPL

To do: Plot SPL vs. frequency for a given Sd