Sound Level Meters and Real Time Analyzers can measure the acoustic level of frequencies below human hearing.
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I know , that's what I mean by :
"dbSPL is an actual acoustic measurement , doesn't have the IEC curve like dbA , so it's not what humans are hearing but the actual acoustic output. It's what instrument are "hearing ".
Anyways , it's sad to see "serious" companies playing with numbers to make people believe stuff that don't exists so they will buy it.......
Here's an example of published numbers from another manufacturer , it's a dual 21'' sub , 7200w peak , so you'd think that thing would create an earthquake , but no , they say 20-400hz @ -3db
That's more realistic....
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8hz - 95hz @ -3db ....... come on !
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Below is a chart from an article testing a Bag End S21E.
Note that the sub is fairly flat @ 80dB & 90dB.
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That's a good example !
You can see that there 16/18db between 15hz and 70hz , would probably be 25/30db if you would see it 'tlll 8hz.
So that speaker response should be written as 30-80hz +-0db , or 15-100hz +-18db from what we see here.
From the link you posted:
"The 21-inch-diameter driver used in the S21E was the largest in the survey, offering nominally 36% more radiating area ("bore") than the 18-inchers that will appear in Part 3. In this case, the increase in sheer driver real estate does not necessarily transfer directly into pants-flappage factor. In a system that rolls off at 12dB/octave throughout its operating range, it takes a considerable low-frequency boost to produce the same sound pressure at the lowest frequencies that 1W produces at 64Hz. At 32Hz, the power required to perform this feat is 16W; at 16Hz, the power required is 256W and at 8Hz the power is a sobering 2kW—well beyond the manufacturer's recommended limit of 800W. And at frequencies where one feels bass as much as hears it—below roughly 25Hz—the aforementioned electronic boost, and the ear's natural insensitivity to bass at low to moderate playback levels, combine to impose excursion demands that a single driver—even a 21-incher—simply can't meet. "
You can see that there 16/18db between 15hz and 70hz , would probably be 25/30db if you would see it 'tlll 8hz.
So that speaker response should be written as 30-80hz +-0db , or 15-100hz +-18db from what we see here.
From the link you posted:
"The 21-inch-diameter driver used in the S21E was the largest in the survey, offering nominally 36% more radiating area ("bore") than the 18-inchers that will appear in Part 3. In this case, the increase in sheer driver real estate does not necessarily transfer directly into pants-flappage factor. In a system that rolls off at 12dB/octave throughout its operating range, it takes a considerable low-frequency boost to produce the same sound pressure at the lowest frequencies that 1W produces at 64Hz. At 32Hz, the power required to perform this feat is 16W; at 16Hz, the power required is 256W and at 8Hz the power is a sobering 2kW—well beyond the manufacturer's recommended limit of 800W. And at frequencies where one feels bass as much as hears it—below roughly 25Hz—the aforementioned electronic boost, and the ear's natural insensitivity to bass at low to moderate playback levels, combine to impose excursion demands that a single driver—even a 21-incher—simply can't meet. "
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Yes... but dB levels are indicated in quotations in that diagram which means they're not really "real".
Sorry... I couldn't resist!
