Anyone have a cheaper Delay module in core?

What's it for?

For some things you absolutely need interpolation otherwise it kills the sound, for others you really don't at all. Usually it's a compromise.

e.g. for reverbs, you can use delay lengths that are integer numbers of samples, and get a really great sound (better than interpolated), but then you can't smoothly change or modulate the delay length without very noisy artefacts.

hmm, linear interpolation will increase artefacts, the problem with that in a physical modelling context isn't so much the audio quality, but the consistency of response.

e.g. for something like a karplus style model with the delay in a feedback loop, if the pitch requires a delay setting that has more error due to the linear interpolation, then it's decay characteristic will change compared to a pure setting with less error. It might decay more quickly, or more slowly, and it will also potentially effect the timbre and the amplitude. Of course, this will vary depending on sample rate, so it's not trivial to tune out of the system. Probably cheaper to just use better interpolation in the first place, which will reduce the problem, though not remove it entirely.

It would be worth setting up some A/B tests with linear vs cubic vs laplace or something, making sure to test/compare lots of different pitches and different sample rates, trying to find where the linear interpolation is at it's worst before deciding which to use.