11-Oct-2015, 19:23
I don't think a Phantom would explode if you open it, as I don't expect any static pressure difference vs outside air.
I have no idea about how the 1.2 ton force to seal the box is meaningful for us, beyond being a parameter of the manufacturing process.
Regarding the internal pressure, I did the math earlier when this figure was released, and could confirm:
Nominal volume is 3 liter (for each woofer). Excursion is +/-12 mm, as read on the web.
Volume change, each way, is 1.2 cm * pi * (10 cm)^2 = 377 cm3 = 0.377 liter peak
Relative volume change is 0.377 / 3 = 12.6% peak (+/-12.6%)
PV = nRT => assuming temperature is constant, relative pressure change = relative volume change = +/-12.6%
Rounding atmospheric pressure to 10^5 Pa, amplitude of pressure = 12.6 kPa pk
RMS pressure = peak pressure / sqrt(2) = 8.9 kPa RMS
https://en.wikipedia.org/wiki/Sound_pres...sure_level = 20 * log10 (pRMS / 20 µPa) = 173 dB
So the 174 dB in Devialet's white paper looks correct, and pretty unusual in less loud and/or compact speakers.
Hope it helps.
I have no idea about how the 1.2 ton force to seal the box is meaningful for us, beyond being a parameter of the manufacturing process.
Regarding the internal pressure, I did the math earlier when this figure was released, and could confirm:
Nominal volume is 3 liter (for each woofer). Excursion is +/-12 mm, as read on the web.
Volume change, each way, is 1.2 cm * pi * (10 cm)^2 = 377 cm3 = 0.377 liter peak
Relative volume change is 0.377 / 3 = 12.6% peak (+/-12.6%)
PV = nRT => assuming temperature is constant, relative pressure change = relative volume change = +/-12.6%
Rounding atmospheric pressure to 10^5 Pa, amplitude of pressure = 12.6 kPa pk
RMS pressure = peak pressure / sqrt(2) = 8.9 kPa RMS
https://en.wikipedia.org/wiki/Sound_pres...sure_level = 20 * log10 (pRMS / 20 µPa) = 173 dB
So the 174 dB in Devialet's white paper looks correct, and pretty unusual in less loud and/or compact speakers.
Hope it helps.
