Hi @ PD forum

As usual I'm back with basic questions. It seems very frustrating to be constantly blocked by very simple problems which are often not really explained (or not that I can find) elsewhere.

Problem this time is on windowing (and I suppose arrays). How does this work properly? I'm busy trying to understand certain aspects such as a 'crown' ... what is this? I understand it's a type of wave-form with a size of 22050 but where can I find some information on this and what there are used for?

In Johannes Kriedlers book he often talks about 'crowns' and has them as small windows - are these actual size or just an image, or are they meant to be in a sub-patch? He also talks about 'windowing', but what exactly is this, just a sub-patch with an [inlet] or [send/receive] box in the new patch?

Sorry to ask such basic questions, but unfortunately none of this is explained clearly anywhere (or not that I've noticed). If anyone could clarify these point - I'm sure I'll have other questions - I'd be most grateful as I'm going round in circles on this one.

I've included a loop-generator patch from Kriedlers Loadbang (one of the many) where he keeps mentioning 'windowing' and 'crown' ... but unfortunately I can't get it to work, probably due to not understanding the above problems. Feel free to add bits and comments etc if it's of use. Or even links to explanations on the web also.

BIG thanks in advance.

http://www.pdpatchrepo.info/hurleur/loop_generator.pd

Hey, can you post a link to where in the book he's talking about those things? Sometimes people use those terms a little differently, so it would help to see what context he's using.

Hi Maelstorm

Me again, still asking simple questions.

I'd be happy to post the link, do you have the book or should I look through the internet version and find a way of explaining 'where' I find the problem?

Big thanks.

He has it all online here:

http://www.pd-tutorial.com/

Edit: sorry, read your post too quickly. Yeah, post a link from the online version. It will be more beneficial to others reading, anyway.

I've quickly checked the book (online and pdf version).

Section Wave Shaping : 3.5
Example : patches 3-5-1-3 wavgorithm+sin+fenster.pd
Page 13 of 23.

The example that starts mentioning a 'crown' (you'll see what looks like a little array) and also 'windowing' in the comment next to [*~ 22049].

I tried to make this patch but came to no good, at least it doesn't work, I couldn't even generate a wave - as you'll notice the first part. If I can't get the thing to work that means I can't understand the solution/workings.....aaah!

Thanks again.

Okay. After looking at that, I got the impression he had already tried to explain what a crown is, and I found it here:

http://www.pd-tutorial.com/english/ch03s04.html

in the 3.4.2.5 Loop generator section.

A window is really just an amplitude envelope, though you normally see the term "window" referring to a very short amount of time, such as in granular synthesis or FFT.

But in this context, it's just an amplitude envelope whose purpose is to eliminate clicks. It does this by making sure the sample starts at zero and fades in, and then fades back to zero when it reaches the end. Doing this ensures that when you loop the sample, it won't suddenly jump from one sample value to another. Those jumps are what cause the clicks.

The crown is just a specific window shape (you also might see it called a "trapezoidal" window). It's basically just a quick fade-in ramp, a sustain, and a quick fade-out. Crown shapes are generally useful for long samples in which you don't want to affect the sound, you just want to fade in and out to get rid of clicks.

Also, the actual length of the window does not define it. It can be 100 samples or 22050 samples or whatever. Longer windows just require less interpolation.

I've attached a patch that shows a cheap way to get a crown window by taking the positive half of a cosine, amplifying it, and then clipping it. I also included a Hann window and an example of both in use so you can see more clearly what they do.

Hope that helps.

http://www.pdpatchrepo.info/hurleur/windows.mmb.pd

Big thanks Maelstorm, I'll check through this info and get back to you, thanks again.