Distortion in phaser module

Software Development
1

Hi all, I am desperate for help here. I am trying to implement the Phaser module from DaisySP and get terrible stepping and distortion in the signal.

I have tried setting all of the different parameters and cannot get a clean signal or good phaser sound. I have tried attenuating the signal before sending it to the phaser but that hasn’t made a difference. I’ve even programmed the phaser example with the Daisy Web Programmer and that has distortion as well.

The other modulation effects, like the flanger, work perfectly with no distortion.

Can anyone please help?

2

While I also experienced the stepping in the phaser I’m curious about the distortion, which I did not have. Can you share some dry/wet samples, and more information about your circuit?

3

I think I may have just found a culprit (although I don’t understand why).

I was using the AudioCallback function with the Interleaving buffers. I just changed it over to the AudioCallback with the standard input/output buffers and it appears to be clean now. I am slowly adding the rest of my app back in now to make sure nothing else was causing it but the different callback parameters seem to be the issue.

4

Hi, reviving this thread because I’m having the same issue where the Phaser examples have a lot of digital crackling, even though I’m using the non-interleaving buffers. Did you end up figuring out what was causing this? The other modulation effects work fine for me as well. I’m plugged into a pedalPCB terrarium.

Could you share your working code so I can try to load it onto my unit? I’d really appreciate it.

5

Hi, sorry for the delay. If I remember correctly, it was the interleaving buffers that fixed the issue.

Here is my code if you’d like to give it a try (I was also building this on a Terrarium PCB)

6

I can’t imagine how the interleaved vs non-interleaved buffer can affect this, unless you were just indexing into the buffer incorrectly.

The Phaser class operates on one sample at a time. It doesn’t know where that sample came from, or where it goes, and any overhead difference between the two buffer types is too small to affect the CPU load.

7

Thanks for the reply! I am having some trouble with your github repo though. Still need to try flashing from my Mac with an older pull, I’ll post updates.