Rotary - Classe Audio CP-500 - V2.4 Owner's Manual

rotary

The rotary knob on the front panel does not directly control the volume. Instead, it
controls circuitry that does so with greater fidelity and precision than traditional volume
potentiometers could ever achieve.
Since the volume control circuitry is under software control, it is possible to customize
its behavior under various conditions. To better understand why this is so valuable,
consider two scenarios:
Person A places a high value on precision in achieving exactly the volume
setting that makes the music most realistic; being able to easily change volume
setting by a fraction of a decibel is critical to his enjoyment of the system.
Person B just wants to jump easily from low volumes to a reasonable listening
level, and is less concerned with the finer points of precision than with getting
what he wants with a quick twist of the knob.
You can see the problem in these scenarios: Person A wants extremely fine gradations on
the volume control, which will require many rotations to go from extremely low setting
to normal listening levels; Person B wants to get from one to the other with a "quick
twist" of the knob, requiring coarse gradations in order to cover so much range in so
little space. What happens when Persons A and B live in the same house? Or if Person
C wants to have both, depending on their mood at the moment? (In fact, most of us are
probably like Person C.)
Classé solves this dilemma by altering the response of the volume control, based on
several factors.
Since it is rare to listen at extremely low (barely audible) volumes, the low range
adjustment of the volume control allows for faster response to knob input when the
volume setting values are low. When activated, you will get from extremely low to
middle volume control settings a bit faster than you would otherwise. This effect can
be subtle, and may not even be desirable when the speakers used have extremely high
sensitivity (since this results in using the lowest part of the range more than you would
otherwise).
The most significant factor in the perceived responsiveness of the volume control is the
speed at which the knob is being turned. We all naturally tend to move volume knobs
more quickly when we need to make a bigger change, and we tend to slow down as
we approach our desired volume. Thus, if the CP-500 sees the knob moving relatively
quickly, it uses coarse steps to effectively accelerate the action of the circuitry. As the
knob begins to turn more slowly, the CP-500 will actually increase the resolution of the
steps, which slows down the action of the volume control and yields greater precision in
choosing an appropriate setting.
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