Andy Gulliver wrote:
... and don't forget to allow for the effect of the Coriolis force, as outlined
in the following which is from a Hi-Fi forum a few years back (around the time
people were using green ink round the edge of CDs):
Another consideration is the coriolis force which causes electrons
to spin around the edge of plated through holes as they pass
from one level of the board to another. Since the direction
of spin around the hole does not change whether the electron
is going down the hole or up the hole, the component of current
around the hole is a full wave rectified or frequency doubled
version of the total current, causing second harmonic distortion.
SECOND harmonic distortion? On AUDIO signals? Oh, must be really
BIG vias. You can calculate the resonant frequency of current circling
around
a via hole, and it is going to be well into the microwave region.
Also the coriolis force changes direction from the northern
to the southern hemisphere and changes magnitude with latitude,
being strongest at the poles. This is the reason the right
stereo channel sounds better in the northern hemisphere and
the left channel sounds better in the southern hemisphere.
The Coriolis force is very weak on things the size of meso-atmospheric
cyclones, generally many hundreds of miles across. The Coriolis force on
femtograms of electrons in a space less than a millimeter across is going
to be swamped by many orders of magnitude by thermal noise.
For balanced performance all audio circuit boards should
be mounted vertically and in a north south direction. This
not only reduces coriolis effects but also minimizes
Hall Effect voltages due to the earths magnetic field.
Unfortunately I don't have an exact date, but ISTR it was early April that year
:-)
Many of these high-end audio guys are so far from any scientific basis that
they don't reserve stuff like this for the first of April! Check out some
of the audio experimenter magazines - wild stuff.
Jon
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