Chris,
I'll store the picture away for a future avatar.
What I was referring to is the recreation of transients. The speakers should, all, move forward when the transient hits. If they move backward they have not retained absolute polarity.
It gets sticky because most US microphones are wired 180 degrees out from most European ones. Sometimes both US and European microphones are used in a recording.
But what it brings to the table is a clearer voice, the true strike of a drum stick on a cymbal, the proper "pop" of a drumstick on the rim of the snare drum, the proper pluck of a pick on a guitar/mandolin/banjo/dulcimer string. The music becomes more lifelike.
PJ says too many albums are recorded with instruments in no particular polarity. Some are most of mine are not. A "Best Of" album is very likely to have this problem.
The CD and polarity meter allowed me to check a friend's system. It has groupings of three "Ticks" on it. The first two are proper polarity and the third is 180 degrees out. The meter should register green, green, red. Out of polarity registers red, red, green. My friend's midranges were out and it made a discernible difference when when we flipped the midrange amp output wires. He has a 4-way quad amplified system.