There were two stages at Woodstock: The main stage where all the performances took place and a much smaller free stage for alternative performances (not only music).
Main Stage Edit
The main stage was made of wood and was built shortly before the festival, organized by Chip Monk. It was about 20 × 15 × 15 meters and was covered by a big canvas. The towers for the speakers were made of metal and arranged all over the area. Everything was removed after the festival.
In order to speed-up the changeover the stage had a turnable platform which was separated into two parts. The idea was to use the front for playing and the back for setting up the equipment of the next band so they only had to turn the platform around. Unfortunately the equipment was too heavy for the podest so the casters broke soon and it couldn't be turned anymore. The crew had to go back to traditional set-up and tear-down.
Opposite the stage was the FoH (Front of House which hosts sound and light engineers, soundboard, etc.) in a primitive tent. At the back was the recording equipment. Everything was recording on two eight-track recorders which was later used for official releases and the movie.
Free Stage Edit
Beside the main stage there was also a much smaller alternative stage (also known as the free stage) built by The Merry Pranksters and the Hog Farmers. It could be used for free performances. Reports claim that Joan Baez played some songs on this stage before going to the main stage.