1kHz noise with Terrarium board

bretvh

Member
So as I have run into the 1kHz whine more, I've been messing around with changing the block size and/or sample rate. I can get the whine down to about 93.75hz with a block size of 512. Latency is not super noticeable at that rate. And the noise is less annoying. I suppose the block size could be even bigger to get the whine even further out of the human range of hearing, but I suspect latency would become more of an issue at that point. Has anyone else been able to find a way to deal with the 1kHz tone? I tried smaller block sizes, which got it outside of the upper range of hearing, but also resulted in some unpleasant artifacts. Conversely, I tried using a 96k sample rate and that just messes with everything. My reverb turned into a super downtuned and warbly pile of weirdness. It was almost cool. But not quite.
 
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bretvh

Member
Oh, and for reference, you can set your block size inside the main function after your seed.Init() call, with:

Code:
seed.SetAudioBlockSize(512);
 
The 1kHz whine is still bumming me out. I have tried lowering the blocksize down to very low, like 1 or 2 samples, and also have things start sounding strange.

I have a strange noise observation that I have been meaning to make a longer writeup for. I have made 3 Terrarium builds (one is not boxed up) and one of them has acceptably low noise, but the other 2 have enough 1kHz noise to make them unusable. I added a few extra leds to the low noise one, but other than that they should be the same builds. I have double checked and think I am using all the same components and have tried moving the same exact Daisy Seed between them and the noise stays low on the one build. I don't know if there is some difference in the pcbs themselves, but I received 2 of the pcbs at the same time - so I figure that is unlikely.

Has anyone else made a Terrarium that has almost no 1kHz noise? or have two that show very different amounts of 1kHz noise?
 

Dreamlands

Active member
Nope. Only sounds OK if I use it as a passthrough.

Another very specific thought I had to salvage this pedal was to use cycfi's very efficient "bitstream autocorrelation" pitch tracking code to drive the cutoff frequency of a lowpass filter, and tack on an analog lowpass to remove >= 4KHz from the output of the Terrarium. For single notes, this would in effect output the fundamental frequency. Would then pipe this signal into an octavia or green ringer style circuit. The intent would be to essentially automatically ride the treble knob to optimize the clarity of the octave up effect.
 
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bretvh

Member
For what it's worth, the 1kHz noise was not very bad on mine until I added in code to blink the LED in time with the delay. Also, my pedal seems to have developed a little ground issue that I have not taken the time to track down yet. If that fixes the whine, I will post back here. Should be able to do that this weekend.
 

PedalPCB

Administrator
Staff member
For what it's worth, the 1kHz noise was not very bad on mine until I added in code to blink the LED in time with the delay.
Did you use the LED class, or GPIO pins?

The software PWM frequency of the LED class might be finding it's way into the audio path.
 
At least for my 1kHz noise it is not the LED. I have turned off the LEDs and it did not change anything.

More processing (so more things going on) makes the noise worse and it clearly moves with when adjusting the samplerate and blocksize as noise freq = samplerate/blocksize.

I have also tried to implement the same 5V power isolating that the Daisy Petal has (even with the same isolator part number) and it does not seem to change much. I didn't really expect it to change much since the ground is connected through the isolator, but the Daisy creators seemed to think it was the magic bullet.
 

bretvh

Member
Did you use the LED class, or GPIO pins?

The software PWM frequency of the LED class might be finding it's way into the audio path.
Ah, I think I am using the LED class, because I was wanting to fade the LEDs in a while back and then never did that. I will give the GPIO pins route a try and see if I get any improvement. Thanks!
 

bretvh

Member
Today I replaced the damaged pot in my terrarium, and also reflowed the input jack ground connection. It's MUCH quieter now. I was noticing that flipping the toggle switches or footswitches were causing a pop, so I realized that either my damaged pot finally started to short out, or I had a loose ground on the input jack (which was cutting out intermittently if I moved it. I have not yet bumped it back up to a 48 block size or changed the LED code, but this is promising so far and may explain why the noise suddenly got worse on mine.
 

bretvh

Member
FWIW, I tried using the GPIO pins with no change and also just completely disabled the LEDs as @sonic_explorer did and the noise is still there. I'm having a hard time understanding how one would use this platform for a production pedal if their processor whines so audibly when it's working. 🤷‍♂️ While the block size hack brings the whine down to a much lower and less annoying frequency, I am noticing subtle and not-so-subtle differences in the audio quality of the effects when I set the block size to 4.
 

bretvh

Member
You guys. I am here to officially bow my head in shame. Here is a message I just sent to an acquaintance I've been sharing seed noise issue stories with over on Instagram:

"Ok, so I feel like an idiot here, BUT. I was swapping some pedals out of the chain with the terrarium and noticed the whine would stop when I unplugged power from the other pedals. I had them all going through a cheap DC brick. I thought it was a bad patch cable in the chain at first, but then I just went into only the Terrarium. Dead silent. I added another pedal, and as soon as I powered it up from the same DC brick, the whine was back. Putting the terrarium onto a separate DC brick on a different outlet and then chaining it with other pedals maintains the silence. I would say that a) my cheap-ass DC brick sucks because it's not all isolated jacks (I knew this), and b) I that I think the Seed is very sensitive to power supply noise."

This may not fix everyone's issue, but it did help mine tremendously.
 
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Dreamlands

Active member
I hear 1KHz loud and present using either my 30 dollar supply or my much nicer CIOKS supply.

I'm not aware of anybody decidedly solving this issue for general usage, as all of the 1KHz noise threads I've seen on the Daisy Slack appear to be unresolved.
 
@bretvh - I think using an isolated power supply will definitely help lower the 1kHz noise, but like @Dreamlands, it does not make it disappear for me. I have tried using a USB power bank, which is just a fancy battery and should be the cleanest power around, with nothing other than the Terrarium plugged into it and still have significant 1kHz noise.

I think when you daisy chain a noisy Terrarium with other pedals (or use a cheaper non-isolated supply with other pedals plugged into it) the noisy ground and power lines of the Terrarium are effectively poisoning the other pedals and raising the total noise level.
 

ryanpwm

New member
Yo just to chime in, none of you are going to fix the ground issue. And it's NOT the Daisy's fault. This circuit PCB is TERRIBLY designed. They are mixing a computer chip digital ground plane heavily with the analog ground. No wonder you're all getting noise. Seriously, whoever did this maybe knows about analog electronics, but no digital. You CAN'T mix a serious processor chip like this and the analog ground. Not to mention how they leave huge places open for ground loops within the PCB itself. They just decided to use the entire leftover PCB space as one giant ground, which like, yeah ok fine for your fuzz face's or whatever, but not when there's high frequency digital signals on the same ground.

If you want to make any real improvement, the best you can do is get a soldering iron get a thick wire and point to point connect it to the negative power pin that is the main ground for the pedal. Maybe you can reduce the impedance and force it to flow out of the pedal and not into the signal.

The ground plane is noised up by the digital stuff, which has more potential to go out into the audio cable grounds than it does the power ground. It's getting sucked into your other pedals, shot through them and back into the audio signal in a big loop. Which is why some have so much extra noise with out pedals. Power isolation might help there, but again, the noise is bleeding all over what should be a separated analog ground. So the pedal is going to have inherent noise anyways.

And ugh, like... the messed up ground potentials just laid out there. Literally right at exit for the digital ground is the analog signal input ground. And it's CLOSER than the actual power ground out. So no wonder there's a shit ton of noise.

Not to mention the decoupling capacitors on the TL072. Why on earth are they so far away from the chip??? And the chip ground isn't decoupled. It doesn't need to be, but considering how there's multiple other grounds that could see it as a good way to flow rather than the power ground why not?

Pedalpcb f'd up and it's giving daisy a bad name. By the real shit from Electrosmith. You wonder why they don't sell this product on their website?? Cause A, its not theirs, and B, it's a bad design. no decpouple.png Untitled-3.png.jpg
 

zgrav

Well-known member
Thanks for the interesting commentary and illustrations on the terrariuim pcb design after you peel away the unnecessarily scathing commentary about it. The suggestion that this is solely a Terrarium board issue is also at best an incomplete observation given the 1khz whine issues that are extensively discussed on the daisy forums. I wonder if there are some QC issues in the products since I have a couple of Daisy seeds that -- mercifully -- are really quiet.

I am happy that pedalpcb was quick to release a pcb shell for using Daisy in a guitar effect pedal. No doubt we will see other Daisy boards and perhaps a revised terrarium board that pay more attention to constructive design suggestions.
 

Dali

Well-known member
@ryanpwm , you seems to know a lot and willing to help make a better Terrarium version which is very nice!

I just find it unfortunate you decided to use that tone. You may be right at the technical level but really need more work on your social/internet skills.
 

MojoTrwall

New member
@ryanpwm , you seems to know a lot and willing to help make a better Terrarium version which is very nice!

I just find it unfortunate you decided to use that tone. You may be right at the technical level but really need more work on your social/internet skills.

If he could read too.

The title is 1khz noise WITH Terrarium board, which is a Pedalpcb board, sold by Pedalpcb.

And the post is asking in the terrarium board specificaly.
 

PedalPCB

Administrator
Staff member
Yo just to chime in, none of you are going to fix the ground issue. And it's NOT the Daisy's fault. This circuit PCB is TERRIBLY designed.

I won't get into a big discussion about the "quality" of the PCB design but it's at least worth mentioning that the noise issue is just as bad with the official Petal. This is not a problem exclusive to the Terrarium and was reported on the Electro-Smith forums before the Terrarium PCB was created.

Your point about the separation of analog / digital grounds is certainly valid, but I don't believe that alone is going to be the root of the problem.

You can hear the noise in this clip, which is an algorithm running on the official Petal before the Terrarium PCB existed.
https://soundcloud.com/pedalpcb%2Fdaydream-cascades
 
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