Hi everyone!
I'm trying to develop my own reverberation pedal for guitar based on FV-1 chip, but I am new to DSP development. I have studied some information about digital signal processing for audio implementations, but it still seems somewhat compicated. As I've understood, SpinAsm allows to write assembly code for modelling digital filters, but I feel difficulcy with understanding asm commands particularly. Could you help me with my task and give some advice or recommend materials about reverb algorithms and FV-1 programming?
Reverberation pedal
Moderator: frank
Re: Reverberation pedal
Hello Forthan,
My first suggestion would be to download some of the Spin reverb code examples which have many comments in the code as to what the each section of code does. This can then be looked upon as building blocks of each piece of code and much easier to understand as little sections.
Also refer to the spin assembly manual for code meanings. come back with specific questions on how the code is built and I an sure many of us here will be able to answer.
It can be a big learning curve but there is only one way to learn.
My first suggestion would be to download some of the Spin reverb code examples which have many comments in the code as to what the each section of code does. This can then be looked upon as building blocks of each piece of code and much easier to understand as little sections.
Also refer to the spin assembly manual for code meanings. come back with specific questions on how the code is built and I an sure many of us here will be able to answer.
It can be a big learning curve but there is only one way to learn.
www.stanleyfx.co.uk
"It's fairly straight forward, if you want to start it press start, you can work out the rest of the controls yourself."
"It's fairly straight forward, if you want to start it press start, you can work out the rest of the controls yourself."
-
Digital Larry
- Posts: 338
- Joined: Mon Nov 12, 2012 1:12 pm
- Contact:
Re: Reverberation pedal
I believe that most of the Spin supplied reverb examples are variations on the "Dattoro" structure described here:
https://ccrma.stanford.edu/~dattorro/Ef ... nPart1.pdf
They generally have two to four cascaded all passes up front for the first "smearing" and then the reverb ring consists of two or four sections, each of which consists of a couple more cascaded all passes going into a longer delay line with feedback (aka a comb filter).
The delay lines in the reverb ring have to be a certain minimum length or it starts sounding more like a resonant flanger than a reverb. I've also heard tell that delay line lengths should be mutually prime so as to try to avoid resonances.
You may also come across "Schroeder" and "Freeverb" structures. For whatever reason, I have not seen any/many of these implemented on the FV-1.
Spin ASM is interesting because it represents all pass and comb filters exceedingly efficiently. Exactly why it is so good for building these structures. So, you have to learn what an all pass filter looks like, and a comb filter, and then you will start to see those patterns everywhere in the given reverb examples.
Also note that a number of the algorithms use the chorus feature to do reverb "smoothing". This was one of the hardest things for me to wrap my head around. Also you may see "the same thing done different ways".
https://ccrma.stanford.edu/~dattorro/Ef ... nPart1.pdf
They generally have two to four cascaded all passes up front for the first "smearing" and then the reverb ring consists of two or four sections, each of which consists of a couple more cascaded all passes going into a longer delay line with feedback (aka a comb filter).
The delay lines in the reverb ring have to be a certain minimum length or it starts sounding more like a resonant flanger than a reverb. I've also heard tell that delay line lengths should be mutually prime so as to try to avoid resonances.
You may also come across "Schroeder" and "Freeverb" structures. For whatever reason, I have not seen any/many of these implemented on the FV-1.
Spin ASM is interesting because it represents all pass and comb filters exceedingly efficiently. Exactly why it is so good for building these structures. So, you have to learn what an all pass filter looks like, and a comb filter, and then you will start to see those patterns everywhere in the given reverb examples.
Also note that a number of the algorithms use the chorus feature to do reverb "smoothing". This was one of the hardest things for me to wrap my head around. Also you may see "the same thing done different ways".