Hi Guys, Doing mixes of original material at the moment with band. Working on project and using NIMBUS for reverb on a number of tracks. I decided to mixdown the track today via export to wav .. all well until it got to the end of the export to wav when out through my seinnheisers came a shrill multi whistle tone even without the track playing, to stop it I killed the audio engine temporarily but put engine back on and noise back. I listened to the resultant wav and it was nothing