interpolation algorithms for delay lines, etc

Cool. I've never got to grips with interpolation. Good to have something to look at.

Cool, thanks for sharing. :)

Very nice. I'm working on a delay-ish type plugin right now! It's like you read my mind. Thanks :)

Very nice, I hope this comes in handy. I didn't want to turn this into a TLDR kind've post, but there are limitations to these different methods. If you have a continuously varying delay (i.e. every sample), for instance, the recursive algorithms probably aren't for you, maybe the "smooth" method instead. Something like the Hermite might be, but you'd need to make sure you get four data points, that is, two samples before and two samples after the spot where you want to get that fractional delay. I guess the point of it all is that having algorithms which don't kill your top end as much as the linear method allow you the freedom to choose how exactly you want to filter the results.

I've had occasional attempts to play with delays but I never figured out how to smooth out changes to the delay time. I'm guessing this is the stuff I need to know but I'm not sure how it would be applied. Say I have a buffer of 100 samples for the current delay. If the params change so the buffer becomes 130 samples, how would I expand the buffer content to the new size? Not trying to preserve pitch or anything fancy, just a tape delay speed up/slow down thing.