These two post have been made on the SOund on Sound forum and as I can't answer them maybe you can post some help here that I can pass on.
1) no its not one of the patches. It has started doing this today after working flawlessly since installation. Every time I load an instance this high pitched, digital sounding, loud whirl appears, sometimes it goes when I select a patch, but then Atmosphere behaves erratically - occasionally not recording any midi data. All the my other Logic Pro and third party audio instruments work fine, including Stylus.
Any idea of what this can be?
Many thanks in advance
A reply posted to the above
2) I don't know what it is, but I get the same kind of thing with Trilogy.
I daresay a re-installation might cure it, but Spectrasonics demand so many hoops are jumped through for installation, it's hard not losing the will to live whilst doing it.