ESPSYNTH86 doing R2D2 stuff

MapacheRaper · Joined: Feb 15, 2018 Posts: 166 Location: Spain

The audio comes directly from the mic Phone, so excuse the quality. Live it sounds way clearer and crispier

It´s a generative patch doing kind of R2D2 sounds from some wavetable oscillators, FMs by wavetable LFOs and a semiimplementation of the karplus strong algorithm.

The hardware is a wemos d1 mini, trought a 4051 multiplexer and running the fantastic ESPSYNTH86 software by Budi Prakosa:

https://github.com/esptiny86/espsynth86

The video is here:
https://www.youtube.com/watch?v=uRPdX0R1gKY&feature=youtu.be

MapacheRaper · Joined: Feb 15, 2018 Posts: 166 Location: Spain

The basic wiring diagram

Remember to power the 4051 with the 3v3 and GND coming from the ESP board (not shown in this sketch schema) and add as many pots as you want following the same logic until 8

conection schema.jpg

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PHOBoS · Posted: Thu Feb 21, 2019 8:03 am Post subject:

I am not really sure what you are doing but it sounds great. Razz

(pin 7 of the mux shoudn't be floating though)

MapacheRaper · Joined: Feb 15, 2018 Posts: 166 Location: Spain

PHOBoS · Posted: Thu Feb 21, 2019 9:18 am Post subject:

ah I see, I was a bit confused about the patch diagram assuming it doesn't actually run on a PC.
So it's a bit like a Nord micro modular ?

badgeek · Joined: Mar 01, 2014 Posts: 2 Location: indonesia

MapacheRaper · Joined: Feb 15, 2018 Posts: 166 Location: Spain

Welcome to the forum, Budi! party time!

Yeah, I would love to do an eurorack version of the pcb with a cool design, but Im still learning kicad. It´s a pity cause I have the design crystal clear in my mind but the footprints and library stuff of Kicad drives me craaazy!.

Grumble · Posted: Thu Feb 21, 2019 2:49 pm Post subject:

Hey...this is very interresting Shocked

cementimental · Joined: Jun 07, 2011 Posts: 14 Location: London

Sorry to revive an ancient thread! Great sounds and thanks for sharing what's almost the only info about ESPsynth86 online, outside of the github :-S

I had been looking for a node-editor-based synth library for a board that's currently cheap and easy to find, so was excited to recently discover ESPsynth. Got it basically working thanks to the wiring info in your post but I'm having some issues. On the offchance that you will even see this all these years later I thought I'd just run it by this thread Smile

I'm programming the board using Arduino IDE, it compiles and uploads fine, multiplexer knobs operate correctly, but it's just that the audio is extremely distorted. The waveform exhibits extremely loud spikes rather than clipped peaks, so it looks/sounds more like some kind of buffer underrun or digital crossover distortion.

When I make a simple test patch with a volume control VCA I find that the distortion seems to suddenly appear as soon as any sound goes above 50% volume. At low volumes the waveforms look and sound normal.

I've tried NodeMCU and Wemos D1 Mini boards, hear the exact same distortion on either one.

I'm using the PDM output settings with a simple resistor and cap filter. Don't have a proper DAC to hand but I tried a little MAX98357 amplifier board kit, it was hard to tell thru a tinny small speaker but it seemed to be having the same or a similar issue, didn't sound right at all.

Have tried different sample rates and bitrate in the code but that doesn't help, as well as all the different board settings I can.

I'm using a CD4051 multiplexer for the input knobs but the problem is definitely unrelated to any issues with that, as it occurs with test patches without the multiplexer connected at all

MapacheRaper I tried your patch downloaded from the youtube comments and it too sounds completely distorted, not at all like it does in the video.

Any ideas would be much appreciated thanks. Smile

But yeah, olde thread about a library that doesn't seem to have been used much at all so no worries if not Smile

PHOBoS · Posted: Thu Jan 30, 2025 2:13 pm Post subject:

Since it's a digital output and you say it's working otherwise could it be a hardware problem ?
Maybe a resistor to ground (say 10K) at the output after the 10uF cap might help.

cementimental · Joined: Jun 07, 2011 Posts: 14 Location: London

Thanks for the reply, have tried that but alas it doesn't help. It definitely sounds like something wrong software-wise, it's a very digital sounding underrun/distortion kind of sound.

Wondering if I somehow did something wrong in the first place while installing the board and libraries etc.

I had to edit one or two things to get it compiling without errors in the first place, e.g. based on some forum info somewhere I added "compiler.libraries.ldflags=" under "compiler.elf2hex.extra_flags=" in the existing platform.txt file in Arduino15/packages/Espsynth86/hardware/esp8266/2.5.0/platform.txt (don't fully understand why but without that it wouldn't compile at all)