What is the difference between single pan balance and physical balance?

Answer 1

In music, pan knobs are used for mono input lines to control how they are mapped to stereo output lines. On the other hand, for stereo input lines, the knob is labelled "balance". So you should get a PAN control for mono lines and a BALANCE control for stereo lines (and none for lines with more than 2 channels).

In the Sun J2SDK, PAN controls behave like BALANCE controls for stereo lines and BALANCE like PAN for mono lines. However, this is only a convenience for compatibility. To write portable programs, you should not rely on this behaviour. (Matthias)

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Answer 2

A single pan balance has one pan where the object being weighed is placed, while a physical balance has two pans for comparing the weights of two objects. Physical balances are more precise for measuring small differences in weight compared to single pan balances. Single pan balances are typically used for simpler weighing tasks, while physical balances are used in more precise scientific measurements.