boramides – have you tried listening to the recordings of the Salisbury sample set posted on Contrebombarde? Go to
http://www.contrebombarde.com/concertha ... ced_searchthen in the Organ search box look for “MDA – Salisbury Cathedral Father Willis”.
Click on “Search”, and you should have fifty three pages of performances to choose from. The site does use mp3 compression, which can obscure finer details such as reverb decay, but it might give you some useful sounds for comparison.
Recordings of the pipe organ are available on youtube, for instance a varied selection of music played by Michael Murray in an excellent recording by Telarc:
https://www.youtube.com/watch?v=5XcOfjlnbQ0The first fanfare is quite short, and at the end the decay of sound from the famous Tuba can be heard clearly. Of course youtube is compressed too – but you could buy the actual CD for maximum fidelity.
How many speaker channels are you using? Too few can result in types of distortion that sound like noise:
http://www.pykett.org.uk/EndOfPipeOrgan.htm