Aeolus is a synthesised (i.e. not sampled) pipe organ emulator that should be good enough to make an organist enjoy playing it. It is a software synthesiser optimised for this job, with possibly hundreds of controls for each stop, that enable the user to "voice" his instrument. First presented at the 2nd LAD conference in Karlsruhe, end of April 2004. Main features of the default instrument: three manuals and one pedal, five different temperaments, variable tuning, MIDI control of course, stereo, surround or Ambisonics output, flexible audio controls including a large church reverb.