Thanks, all, for the suggestions.
Alas - I ensured the metronome is turned off; went into Windows control panel and turned Sounds > Sound
Scheme to “No Sounds”. I went into Program Events and double checked that every system sound is listed as “none”.
But I still get event sounds in Cubase. And only in Cubase.
Not typical Windows sounds. It’s making piano sounds. When I click “play”, it sounds C6. When I hit ‘stop’, I get B5. When I select track 1, I plays C1. Select track 2, get D1.
This is Cubase 7.5, Windows 7-64, through an RME UFX connected by USB. I have shut off/disconnected all input intruments, so it can’t be triggering an external MIDI or anything.
Update - I turned off the Fireface and turned on the computer speakers to take the UFX out of the equation. Same result, just out of the computer speakers in stead of the mains.
Update 2 - I should note that when I start Cubase, I get a message “Missing Ports” - Microphone 1 & 2 In Unmapped and Speakers 1 & 2 Out unmapped - but I’m guessing this is because I’ve disconnected everything.
Update 3 - I’ve disconnected tracks 1 & 2 from input and output busses, no change.
Update 4 - I just noticed - when I click on something that makes a sound, there’s a spike in the MIDI Out Activity meter of the Transport Panel. And, when I open th eVST Performance window, it’s showing a small but non-zero average load and small but non-zero fluctuating real-time peak, even though nothing is happening.
This last point seems significant - but what to do about it?