Hi guys.... I am currently working on putting together a custom vintage sounding sampler in PD....

I realized that most tutorials, exemples and ressources online are very concerned about ANTI-ALIASING (ie how to not get aliasing in the sound).... My goal is pretty much the opposite ... I DO want aliasing and I want the texture of the aliasing to change when the playback speed of the wav file changes... So I am guessing the pitching part has to come after the part that introduce aliasing to the sound...
So far, I am playing with the phasor, samphold and a vslider to pitch up and down .....

I would like to know if there are any other ways to do this and/how I can improve the process ?

Thanks in advance (while I keep browsing the web looking for ideas and inspiration )

@dadasane yeah the easiest way is to sample every x samples without any filtering.. Of course, you can only reliably get "predictable" aliasing at integer divisions of the sampling frequency afaik.. you could also upsample first, (and use an upsampling filter) and then decimate (downsample) in order to get more resolution

if you want to sample at other frequencies besides integer divisions of the samplerate, you have to do some kind of resampling - figure out the "correct" inter-sample value, then interpolate back to the original sample rate by low passing the hypothetical "sample-and-held" signal below the nyquist frequency

Yeah the frequency is by no mean an multiple of the original sampling rate (44.1Khz).
I'll figure something out.

Thanks Seb

So I have searched and searched again and the best way for me to acheive what I want is to be able to modify the playback speed AFTER the sample and hold .... And this is where I am stuck....

Basically my patch load the wav file, then I have a phasor with a hslider to control the playback speed and another one for the sample rate and then I have the sample and hold and then I end up on the tabread and the dac ....

Is there any way to control the speed at which the rabread actually go through the array ? (I am not even sure that it would have the desire effect) ... Once again, my goal is to pitch up or down the aliased signal in order to generate even more aliasing .

@dadasane Why not load the sample in an array, play it through the sample rate/bit depth reduction and record the output into another array, and then have the sampler read that instead of the original sample? I made a sampler like that once and it sounds interesting, it might not be exactly what you're after but you could try it all the same. Another important thing is to use [tabread~] instead of [tabread4~] for more crunchiness.

I'm not sure how you would do it faster than realtime but for short samples of a few seconds it shouldn't be a big issue, and you can save the aliased samples as well.

I have managed to do what I wanted... And yes I am using tabread

Here is a demo : https://mega.nz/#!8oVn0QQK!ywcBonPZhRAeA7lWpPKRUZGTgziW1woOxelL44AqLUg

@weightless Do you have an example of the implementation of loading the sample in an array,and recording the output into another array ? I would like to give it a try

@dadasane Here is the sampler I mentioned. I left it before finishing it but it kind of works like a hardware sampler would in principle. Open sampler16~-help.pd, load and play an audio file in the yellow abstraction on top (this would be the equivalent of your live input, you can connect an adc~ there as well). Then on the purple abstraction click the red R button, this records 1 second of the live input with the specified bitrate (you can change both length and bitrate in the number boxes). I suppose you can add the samplehold~ mechanism to reduce the sample rate as well as the bitrate. Once you see the updated waveform you can play it like a sampler. Might not be what you were after, but I like how it sounds.
I hope I've included all abstraction to make it work, let me know if something is missing. You also need shadylib for the envelope.
sampler16~.zip

@weightless hey it's seems to be great but I " store.param $0 sustain" is missing
...
still got it some where?
thx