When there is no aliasing to worry about, i might set the cutoff to pi
again...
On low sample rates (22kHz), the lower cutoff is definitely noticeable.
Btw. I just implemented sharing of the interpolation table of the
delreadsinc~ object according to your suggestions.
It counts the number of references and frees the pointer when no object
uses it anymore.
Best wishes,
Clemens
Am 29.04.21 um 21:03 schrieb Charles Z Henry:
On Thu, Apr 29, 2021 at 12:08 PM Clemens Wegener <clemens@chair.audio> wrote:
Also: Is it really mandatory to choose a filter cutoff below pi, when the input
and output Sample rates match? For a simple static delay that should be the
case.
There is an exact requirement when what you're making is an
interpolator: it has to pass through all the original points!
For that to happen, your interpolating kernel i(t) must have
i(t)=1, t=0
i(t)=0, for non-zero integer values of t
An interpolator will have a cutoff freq at exactly pi rad/sec
So, if you're changing the cutoff frequency or amplitudes, it won't be
an interpolator. It will just be some kind of table reader.
And that's good for performance, I'd say, but your users will have to
know that (and you'll have to justify the choice if it's for an
academic purpose)
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