Retrieves the actual Tempo percentage setting for the given player. The Tempo percentage can be modified calling the SetTempoPerc method.
This method doesn't work with sounds with more than 2 channels (5.1 or 7.1) or if the EnableMixingFeatures property has been set to BOOL_FALSE.
Further details about songs mixing can be found inside the How to mix your songs section.
The Tempo variation expressed in percentage.