I m not sure i understand aliasing well... So anything that's sampled and played back without altering the pitch would not suffer from aliasing? When exactly does aliasing occur? during the DAC conversion, or before that? Let's say i set a karplus-strong resonator to a frequency of 30 KHz (assuming i'm a dog and i can hear a pitch that high), at a 44.1 KHz sampling rate, than what happens? No aliasing at all?



2010/3/31 Derek Holzer <derek@umatic.nl>
I was thinking about this the other day.... is it possible to have aliasing with Karplus-Strong? Because it's a delay line, nothing is being played back at any higher rate than it was sampled at, so no aliasing should be possible. Right? Math-gurus correct me if I'm wrong.

Otherwise, any signal generator needs to be bandlimited or oversampled:

http://en.flossmanuals.net/PureData/Antialiasing
http://en.flossmanuals.net/PureData/GeneratingWaveforms

Frank Barknecht has some spliced-transition trick he uses as well, I'm sure it will come up in a reply or two on this thread as well...

D.


On 3/31/10 6:27 PM, Pierre Massat wrote:
Hi!

I ve been reading the on-going debate about interpolation for a few
days, and it just occured to me that i don't how go about avoiding
aliasing more generally than with band-limited wavetables. If i wanted
to play a sample at a pitch higher than the original, or if i wanted to
use a karplus-strong resonator to generate notes, what would be the
proper way of ensuring that no aliasing occurs? Do people generally use
low-pass filters with a cut-off somewhere below the Nyquist frequency?
Or is there a trick that one can use earlier on in the signal path of a
patch?

--
::: derek holzer ::: http://macumbista.net :::
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