It’s been four entire days 
(since May 6) without anyone answering my Nyquist question: How to delete all samples that meet a certain condition using Nyquist per-sample processing?
I chose the “maintaining/improving this forum” category for this thread as not getting your primary thread answered at all 
is a serious issue in any forum! (Especially since other Nyquist questions did get answered way sooner!) Help would be appreciated …
Sorry to hear that. I effectively left the Audacity team about 3 years ago when Muse Group acquired Audacity. I had hoped that someone from the new team would have been fielding these kind of questions by now.
I’ll take a look at your other post and reply there.
Every audio interface and soundcard has an anti-aliasing filter.
And every proper down-sampling algorithm has an anti-aliasing filter.
If you make your own down-sampling algorithm with Nyquist without filtering (like if you simply throw-away every-other sample) you can get aliasing.
Hi Doug. The post you were replying to was a spammer (now blocked) using the old trick of hiding a link in their post.