Hi,

I'm newbie and I'm trying to find a way to implement simple echo system or any other generic IIR filter based on difference equation...

I've found some information on possible ways but each has its own downsides :

• fexpr~ should do it, but is limited to block size, when I try to change it, then dac complains....
• I've read in some PD tutorial that ("untested feature") one could make size of the block 1 and then make it's own IIR filter, but again dac will complain...

Can I implement generic DSP system with help of difference equation that would work ok on live audio data ?

Thanks in advance,

regards,

Bulek.

newbies don't jump straight into fexpr~!

do you wanna explain a bit more for us old timers?

Hi,

I've found solution how to use fexpr here :

http://puredata.hurleur.com/sujet-2279-change-block-size-analyse-audio

I've put the part with fexpr~ and another block value into subpatch - and that's it...

Thanks,

regards,

Bulek.

Are you just trying to do a simple echo delay? Because if so, you'd be much better off using [delwrite~] and [delread~] or [vd~].

@Maelstorm said:

Are you just trying to do a simple echo delay? Because if so, you'd be much better off using [delwrite~] and [delread~] or [vd~].

Hi,

thanks for reply and help. Yes, you're absolutely right. What I'm trying to do is to show Puredata to my students for DSP class and first step would be to show them how to implement generic DSP system by using difference equation - we use that concept a lot during lectures and exercises...We don't have time to go into details, but just quick introduction. I think that knowing about great open source tools is essential for them....

So for a intruduction, I show them FIR block and fexpr blocks, and point out that there are other more efficient ways to do the same in Puredata...

Really great system, I also see that you've contributed great amount of useful patches...

Thank to you and to everybody else....

Regards,

Bulek.