> A major problem with polar plots is the near-universal use of log
> (dB) scales for the plots. This distorts the shape of the plot
Dan,
Sorry to disagree but the reason we use decibels is because we hear in
decibels. A linear cardioid plot looks as if there is very little side
pickup, instead of just being a little less sensitive which is how it
sounds.
Similarly, starting first at say 5 metres, if you double the distance
to 10 metres, wind the volume back up, then double it again to 20
metres, the level still drops by the same amount to the ears and to a
dB meter (6dB each time). On a linear scale, it would drop twice as
much the second time. The same applies to a polar plot.
Our hearing range is about 90dB from threshold to pain. That is a
linear energy ratio of 1 to 1,000,000,000. If we didn't have decibels
we would have to do a multiplication or a division every time we moved
a level control.
David
David Brinicombe
North Devon, UK
Cogito cogito ergo cogito sum - Ambrose Bierce
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