flaky graph, Temple University ??
bah
not addressed at all, other than by Cathar as usual, is the pitch of the noise from the D4;
different frequencies 'carry' more than others, lower being less pervasive and objectionable than higher
the "A" curve (as in dbA) measures spl over a specific range, a high tone/whine can 'sound' louder than the dbA rating might suggest
pump users will sort this out pretty quickly
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