Hi,
You are absolutely right! The PB-1000 is a nice little sub, but it can't produce those numbers. That review has been quoted before, and it's almost impossible to know what the actual numbers would be, just based on what the reviewer says. Here is his description of his measurement methodology:
"Measurements were made at 3 meters and scaled up to represent the results at 1 meter."
If we assume that the measurements were made outdoors and away from any structures, then you could subtract -6dB from the measurements listed. But, the fact that he started at 3 meters might suggest that he measured indoors, and that would inflate the measurements. But, he also doesn't say whether he measured peak SPL's or RMS. The difference between peak SPL and RMS SPL is another -3dB.
Typically, if you were scaling a measurement to 1m, you would also be measuring peak SPL in order to conform to the original CEA-2010A spec. If he measured that way (outdoors), you could subtract -9dB from his measurements. As you know, all of the measurements on the page you cited were done outdoors, at 2m, and they were RMS measurements.
I really can't figure out exactly how he measured from his description. But, best case, you would subtract at least -6dB (and probably -9dB) from his numbers. Just for comparison, the newer 12" PB-1000 Pro measures 101.1dB at 20Hz. Based on that, I would guess that the PB-1000 would be around 100dB or a little less at 20Hz.
SVS PB-1000 Pro and SB-1000 Pro Subwoofers Conclusion | Audioholics
Regards,
Mike