Hey there, I’m working on a stereo pitch shifting delay in Plugdata on a rev 7 daisy, seated on a Funbox board. It’s quite a large patch and I am noticing I am getting a ton of noise, which changes in frequency based on the block size I use. Unfortunately I can’t get the block size low enough to drive the noise to a high enough frequency to be cut by the onboard output filter. Lowering the block size to below 40 causing audio errors and distortion.
Are there any other ways to make the noise high frequency or to just reduce the noise? It’s disappointing that I am still well within the SD memory but essentially can’t run a patch of this size with useable results.
Hi Dave!
I’m sorry to hear about the output being noisy.
It’s possible that the audio is distorted since the CPU is being pushed.
I recommend making a backup of the current patch and then start eliminating some parts. For example, how does it sound when the patch is mono rather than stereo?
Also, does your pedal sound distorted even with a patch that’s just the input going straight to the output?
Hi Takumi, thanks for your reply. The audio distortion only comes when I lower the block size, and with a pass through test patch the whine is much more quiet and I don’t have the distortion. I have become optimizing the patch but I ideally don’t want to lose functionality or stereo. Is it normal behaviour that a patch would fit fine on the Daisy but only be able to run undistorted with a high pitched whine? From what I’ve read online this issue likely wouldn’t happen with an old rev daisy seed.
Thank you for the confirmation. Lowering the block size will require more CPU usage which can lead to noise/distortion if you’re pushing it.
A patch can still be CPU-intensive even if you keep it at a small size from my understanding.
By the way, which flashing option have you been using?
What kind of controls do you have to your patch and how are you connecting these?
On Daisy the controls are updated once every audio cycle, so when you use a lower blocksize they are updated even more often which could result in a higher pitched noise.
Whenever you are transitioning controls to signal rate (objects with a ~) the best practice is to apply some smoothing using a line~ object. I usually use 10-20ms using a [$1 10( message. This assures that all signal operations get a continuous and smooth value rather than glitchy updates every audio cycle.
Not saying that this is the definitive cause of your issue, but it comes up a lot when users report noise issues when using PD/Heavy.
I’ve had the most success in compiling a .bin file from PD using the sram_linker_sdram.lds linker then flashing to the daisy using the daisy web programmer. Do you think that could have an effect?
Hmm that’s something to try! I have used line smoothing but not on all the ctrl sends. Has this removed the noise or just changed it’s frequency in the past? Because having a higher pitched noise would actually push it up to the frequency that the on board RC filter could handle on the Funbox, so higher noise wouldn’t necessarily be bad.
Tried this out and it didn’t have an effect unfortunately