silly question

[Newton Hunt]

Hi Richard,

Why don't you ask complicated questions?

These are simplistic answers to a very complex subject relating to human
hearing, vibrating membranes, materials, impedance, acoustics and lots
and lots of other stuff I don't know.

You hear things differently by location because of

a.  Phasing, 

b.  Nodes and antinodes

c.  Sound source

d.  Source plane.

Phasing is when two sounds are different enough to produce a beat.  If
the sound source comes from two different locations they become out of
phase at some location or other, hence an apparent reduction of volume.

The antinode is the peak of a sine wave and the node is the point where
is cross the zero line, when graphed.  In practical terms this means
that if your ear or mike sit in a node of a frequency it will be
diminished in volume.  Conversely if the mike is located in an antinode
the volume will appear louder.

Sound may well come from several different location of a board, one
purpose of the ribs, and if your hearing is in a node or a phase beat
the sound will appear quieter.

If you stand perpendicular to a sounding plane (in front of a speaker or
soundboard) you will get the full benefit of the vibration.  If you
stand parallel to the plane you will not hear that much.  Tuner's
location is not the best to hear the piano.

Put it all together, sometimes we can hear good and sometimes we don't,
especially when out on the floor from fatigue or booze. :)

Have a great weekend all.

		Newton