A positive pressure to a microphone diaphragm will (in most mics) produce a positive voltage at its output. If the correct polarity (see WFTD archive polarity) of the signal is maintained throughout the signal path this should ultimately produce a positive voltage at the speaker terminal, which will (on most speakers) cause the speaker to move forward creating a positive pressure wave in the listening position. This is known as absolute phase (see also WFTD archive phase): The original polarity of the source sound is thus reproduced in phase by the loudspeaker for listening.