High pitched, bird chirp-like sound effect, heard in trance

[Flyy66]

I've heard it in several songs (usually in trance), but could only find a few instances when I went back to check. I've included them here (Virtual Self - Particle Arts and BT - Flaming June):

https://vocaroo.com/17pGya0Q41Ns

There's this kind of symmetry on the spectrum in the Virtual Self song, which is indicative of aliasing from a sample-rate reduction effect, but none I could observe in the BT song, which makes me think it might not be core to the sound.

Any guesses?

[Benedict]

I remember that being on lots of things like 808 State

Lots of reverb.

Mostly I assume a really fast LFO controlling a Filter around the top of its range on a fairly bright sound. Again, lots of reverb (and perhaps echoes)

You can hear elements of that process in these tracks where I make insect and similar sounds



(particularly Pt II Tropical Jungle)