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Originally Posted by pauldenton
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*snort*
That data would place the Laing D4 at a mere twice the volume of an Eheim 1048.
No way on our green earth is that true.
Perhaps if they sat the Eheim 1048 resonating heavily on a piece of wood and then took the readings....
The Eheim 1048, if not vibrating on something, is near totally inaudible at 12".
Secondly, and as a bit of an eye opener for those who know their physics, the sound pressure level drops off at an inverse square to distance.
If sound is being
properly measured at 1x distance (12"), then if properly measured at 3x distance (36"), then the sound level would be 1/9th the amount at 12" distance.
The dBA scale is a log-base-10 scale. This would mean that at 36" distance, the dBA level would be 9.5dBA lower than at 12" distance.
Now take a look at the Eheim 1048 lines again, and we see a 2dBA separation between 12" and 36".
Primarily the results don't match any form of understood physical theory.
Secondarily for there to be such a small difference, one would have to assume that the Eheim 1048 was vibrating against a larger surface and at 36" vs 12" distance the actual distance of the sound-meter from the thing making the noise (whatever the 1048 was sitting on) did not really change much at all.
As we all know, it is possible to construct tests to suit our needs. Its the issue of making it believable that's the problem.