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[sdiy] TeensyLooper

[sdiy] TeensyLooper

2026-01-29 by Heitor Alves

Hi All


TeensyLooper
An audio looper with reverse capabilities and low latency, reverb and based on the Teensy (4 and 4.1) platform.

This project is born out of the "need" for a simple audio reverse tool for my live setup. It will be connected to the AUX1 send/return bus on my console but the main use will be to record and reverse spoken words from old vinyl records. A unit that samples a few seconds of audio (mono) and reverses it playing it in loop mode.

The base is a Teensy 4.0 and it has a 4 second sampling time @ 44.1khz sampling rate 16 bit resolution. You can use a Teensy 4.1 that will increase the sampling time to 8 seconds.

First interaction:

one input one output Rec button Kill button Loop or single shot switch Reverse or forward switch

Code for 4 seconds To Do:

PCB
Front Panel
test reverb FX Code
Test add ons (second interaction)
Second interaction:

Added GATE/TRIGGER control for record and kill function Added Reverb FX (via code and Open Source Library) Added Reverb Size potentiometer Added Reverb WET/DRY potentiometer

Feel free to try it, hack it, change it. Any suggestions are welcomed and if you find bugs or improvements let me know :)

I'm no serious coder so i admit i used chatgpt for the coding part. Hardware wise it's pretty straightforward :)

Thanks for taking time reading this

Re: [sdiy] TeensyLooper

2026-01-29 by Benjamin Tremblay

Some kind of heart emoji is in order. 

I tend to overbuild my Teensy projects until they do way too many things. This is using all the Teensy (and chatgpt) goodness to do one thing well.

And yet, it seems there’s one thing that could be added, perhaps some granular controls. Most basic would be to move a single start/end of sample around at same or variable loop length.
It gets “granular” when the controls have coarse/fine modes.  With great restraint we can forego an OLED waveform display.
But then, shucks, you need at least one ADSR envelope, preferably 2 so you can move the grains (any or all points) differently than the amplitude with the envelope. 

Yeah, this is why you should never let me get involved with design… It snowballs. Menu diving gets into everything. 
The simplicity of this project is beautiful.

Benjamin
Show quoted textHide quoted text
> On Jan 29, 2026, at 7:09 AM, Heitor Alves via Synth-diy <synth-diy@synth-diy.org> wrote:
> 
> Hi All
> 
> https://github.com/HeitorAL9000/TeensyLooper
> 
> TeensyLooper
> An audio looper with reverse capabilities and low latency, reverb and based on the Teensy (4 and 4.1) platform.
> 
> This project is born out of the "need" for a simple audio reverse tool for my live setup. It will be connected to the AUX1 send/return bus on my console but the main use will be to record and reverse spoken words from old vinyl records. A unit that samples a few seconds of audio (mono) and reverses it playing it in loop mode.
> 
> The base is a Teensy 4.0 and it has a 4 second sampling time @ 44.1khz sampling rate 16 bit resolution. You can use a Teensy 4.1 that will increase the sampling time to 8 seconds.
> 
> First interaction:
> 
> one input one output Rec button Kill button Loop or single shot switch Reverse or forward switch
> 
> Code for 4 seconds To Do:
> 
> PCB
> Front Panel
> test reverb FX Code
> Test add ons (second interaction)
> Second interaction:
> 
> Added GATE/TRIGGER control for record and kill function Added Reverb FX (via code and Open Source Library) Added Reverb Size potentiometer Added Reverb WET/DRY potentiometer
> 
> Feel free to try it, hack it, change it. Any suggestions are welcomed and if you find bugs or improvements let me know :)
> 
> I'm no serious coder so i admit i used chatgpt for the coding part. Hardware wise it's pretty straightforward :)
> 
> Thanks for taking time reading this
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy@synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace@synth-diy.org

Re: [sdiy] TeensyLooper

2026-02-01 by H.Sergio Alves

Thanks for your words Benjamin!

I’ve now added reverb to the project using the free verb library and controls for room size and mix, also added a sample start and end point adjustment using encoders. I’ll update the GitHub soon :-)
Show quoted textHide quoted text
On Thu, 29 Jan 2026 at 13:05, Benjamin Tremblay <btremblay@me.com> wrote:
Some kind of heart emoji is in order.

I tend to overbuild my Teensy projects until they do way too many things. This is using all the Teensy (and chatgpt) goodness to do one thing well.

And yet, it seems there’s one thing that could be added, perhaps some granular controls. Most basic would be to move a single start/end of sample around at same or variable loop length.
It gets “granular” when the controls have coarse/fine modes. With great restraint we can forego an OLED waveform display.
But then, shucks, you need at least one ADSR envelope, preferably 2 so you can move the grains (any or all points) differently than the amplitude with the envelope.

Yeah, this is why you should never let me get involved with design… It snowballs. Menu diving gets into everything.
The simplicity of this project is beautiful.

Benjamin

On Jan 29, 2026, at 7:09 AM, Heitor Alves via Synth-diy <synth-diy@synth-diy.org> wrote:

Hi All


TeensyLooper
An audio looper with reverse capabilities and low latency, reverb and based on the Teensy (4 and 4.1) platform.

This project is born out of the "need" for a simple audio reverse tool for my live setup. It will be connected to the AUX1 send/return bus on my console but the main use will be to record and reverse spoken words from old vinyl records. A unit that samples a few seconds of audio (mono) and reverses it playing it in loop mode.

The base is a Teensy 4.0 and it has a 4 second sampling time @ 44.1khz sampling rate 16 bit resolution. You can use a Teensy 4.1 that will increase the sampling time to 8 seconds.

First interaction:

one input one output Rec button Kill button Loop or single shot switch Reverse or forward switch

Code for 4 seconds To Do:

PCB
Front Panel
test reverb FX Code
Test add ons (second interaction)
Second interaction:

Added GATE/TRIGGER control for record and kill function Added Reverb FX (via code and Open Source Library) Added Reverb Size potentiometer Added Reverb WET/DRY potentiometer

Feel free to try it, hack it, change it. Any suggestions are welcomed and if you find bugs or improvements let me know :)

I'm no serious coder so i admit i used chatgpt for the coding part. Hardware wise it's pretty straightforward :)

Thanks for taking time reading this
________________________________________________________
This is the Synth-diy mailing list
Submit email to: Synth-diy@synth-diy.org
View archive at: https://synth-diy.org/pipermail/synth-diy/
Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
Selling or trading? Use marketplace@synth-diy.org

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