Looks as though the Mk.II has some new display modes Jean, what are these I wonder?....
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These are experimental but i believe they will have their utility. A more precise explanation will be provided in the manual.
but quickly:
Inwd stands for Inward direction. As you know the mk-I display the signal from the center out (
Outward) which seems strange because the sound does not come from the listener but from the speakers. This button will revese the display so that the sound will come from the outer circle toward to the center of the screen.
Full-W stands for Full-Wave display. In order to display the music level intensity, the signal must be rectified and then filtered to obtain a readable level display.
But this show a distorted signal which is usually not important because we only need the level, not the detail of the wave pattern.
This Full-W function will eliminate that distortion and display the entire wave patterns. How? I talked about Inward and Outward direction earlier. With the Full-W function, the signal will originate not from the center, not from the outer circle but from a mid-point. This means the negative portion of the signal wave will be displayed toward the center of the screen and the positive portion toward the exterior of the screen.
These functions were not possible with the LM3915 because the voltage references for the package comparators are fixed. They need to be different depending on one or the other selected mode. That is why i created specially designed comparator modules.
Matrix is a solution to mix the 5,6,7 & 8 inputs into the 1,2,3 & 4 channels. For example, ch 5 is the Center Front (CF). In matrix mode, the CF signal will be fed equally to the 1 (FL) and 2 (FR) chanels.
As you may have noticed, there are few other unexplained modes available but for the moment i will only explain these.
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but don't tell ! 
Matrix modes is explained in an earlier post i did today.
