The HPF is engaged when the switch is in the down position. It is a
-12dB/oct filter designed for minimum phase shift in the pass band to
be as transparent as possible.
Super-wide Stereo signals are those where the Left and Right channels
are phase inverted versions of one another. When played back on
headphones or speakers in a good acoustic space a super-wide stereo
signal gives a sense of impossible width without a definite sense of
positioning in the stereo field. Because allows smooth
control of a stereo image from Reversed Super-wide Stereo through
Mono and all the way to Super-wide stereo you can dial in and process
the exact amount of width and positioning you like for your stereo
signal.
Note that the Left input is not normalled to the Right when there’s
nothing patched to the Right input as is common in Stereo modules
which can also be used with Mono signals. This is because patching
identical signals to both Left and Right inputs results in no Side signal,
for obvious reasons. If you’re interested in processing a Mono signal
into Stereo with then patching to just the Left or Right input
and leaving the other unpatched with give you equal signals on both
the Mid and Side outputs so you’ll have plenty to process and create
your stereo signal.
Instead of being limited to only operating in the region from Mono to
Super-wide Stereo, the through-zero capabilities of the allow
you to reverse the stereo image so the Left channel is on the Right and
vice versa. This allows you to create signals that are mirrored through
the stereo axis.