# Audio Synthesis with CircuitPython synthio ## Overview ![](https://cdn-learn.adafruit.com/assets/assets/000/124/368/medium800/circuitpython_fundamental_synthio.jpg?1694572924) https://youtu.be/q4MBm8w-dTM ![](https://cdn-learn.adafruit.com/assets/assets/000/124/652/medium800/circuitpython_propmaker_4692.jpg?1695225352) You can create your own polyphonic audio synthesizer on a microcontroller board using CircuitPython. The `synthio` module makes it sound great and it's easy to use. This guide covers the fundamentals of audio synthesis using `synthio`, including practical examples. You'll be building your own small-but-powerful synths in no time.  ### synthio History The `synthio` library was originally created as single-voice, monophonic square wave player for MIDI files. As of CircuitPython 8.1, `synthio` received significant development effort from [Jeff Epler](https://learn.adafruit.com/u/jepler) to turn it into a 12-voice, polyphonic synthesizer that uses a wide variety of waveforms, while adding filters, envelopes, modulation control, and a ring-modulation effect. Check out the full `synthio` [documentation here](https://docs.circuitpython.org/en/latest/shared-bindings/synthio/index.html#). Warning: ### Hardware Requirements While `synthio` is built into CircuitPython, this doesn't mean that every CircuitPython-capable board can run synthio effectively. Some chips to use for the best results are: - RP2040/RP2350 -- e.g., Raspberry Pi Pico, QT Py RP2040, Feather RP2350 - EPS32-S2 - EPS32-S3 - iMX RT1011 -- e.g., Metro M7 - SAMD51 "M4" (N.B., a bit hard to find these days) - nRF52 -- e.g., Feather nRF52840, CLUE Your chosen board will also need to to support one of the three audio output methods: - `audioio.AudioOut` -- output to a built-in Digital to Analog Converter (DAC) - `audiobusio.I2SOut` -- output to I2S DAC amplifier board - `audiopwmio.PWMAudioOut` -- output of pulse-width modulated square waves that will go through an external resistor-capacitor (RC) circuit to convert to audio We'll cover these in more depth later in the guide. ### Board Check You can check to see which modules are supported on any given board by checking the [CircuitPython.org](circuitpython.org/downloads) download page for that board. In this example, the Feather RP2040 has `synthio` listed, as well as two different audio output modules that will work: `audiobusio` and `audiopwmio`. ![circuitpython_frp2040_4-3.jpg](https://cdn-learn.adafruit.com/assets/assets/000/123/939/medium640/circuitpython_frp2040_4-3.jpg?1692919601) ## Parts You can run `synthio` on a wide variety of boards, as noted above. The simplest hardware to get up and running quickly is the PropMaker Feather RP2040, thanks to its on-board I2S amplifier and terminal blocks to screw in your speaker wires. ### Adafruit RP2040 Prop-Maker Feather with I2S Audio Amplifier [Adafruit RP2040 Prop-Maker Feather with I2S Audio Amplifier](https://www.adafruit.com/product/5768) The Adafruit Feather series gives you lots of options for a small, portable, rechargeable microcontroller board. By picking a feather and stacking on a FeatherWing you can create advanced projects quickly. One popular combo is our [Feather M4](https://www.adafruit.com/product/3857)... In Stock [Buy Now](https://www.adafruit.com/product/5768) [Related Guides to the Product](https://learn.adafruit.com/products/5768/guides) ![Video of a white hand pressing a button to briefly turn an LED strip into white lights. Also wired up to the microcontroller are a servo motor and a speaker.](https://cdn-shop.adafruit.com/product-videos/640x480/5768-09.jpg) ### Mono Enclosed Speaker with Plain Wires - 3W 4 Ohm [Mono Enclosed Speaker with Plain Wires - 3W 4 Ohm](https://www.adafruit.com/product/4445) Listen up! This single  2.8" x 1.2" speaker is the perfect addition to any audio project where you need 4 ohm impedance and 3W or less of power. We particularly like these speakers as they are small and enclosed for good audio volume and quality. This speaker _does..._ In Stock [Buy Now](https://www.adafruit.com/product/4445) [Related Guides to the Product](https://learn.adafruit.com/products/4445/guides) ![Enclosed Speaker with wires](https://cdn-shop.adafruit.com/640x480/4445-01.jpg) For the example videos in this guide we used the parts listed below. Note: any QT Py ESP32-S2, QT Py ESP32-S3, or QT Py RP2040 will work the same for the examples in this guide. ### Adafruit QT Py ESP32-S2 WiFi Dev Board with STEMMA QT [Adafruit QT Py ESP32-S2 WiFi Dev Board with STEMMA QT](https://www.adafruit.com/product/5325) What has your favorite Espressif WiFi microcontroller, comes with [our favorite connector - the STEMMA QT](http://adafruit.com/stemma), a chainable I2C port, and has lots of Flash and RAM memory for your next IoT project? What will make your next IoT project flyyyyy? What a... In Stock [Buy Now](https://www.adafruit.com/product/5325) [Related Guides to the Product](https://learn.adafruit.com/products/5325/guides) ![Angled shot of small square purple dev board.](https://cdn-shop.adafruit.com/640x480/5325-12.jpg) ### Adafruit Audio BFF Add-on for QT Py and Xiao [Adafruit Audio BFF Add-on for QT Py and Xiao](https://www.adafruit.com/product/5769) Our QT Py boards are a great way to make very small microcontroller projects that pack a ton of power - and now we have a way for you to turn many QT Py boards into powerful audio play projects that are super small! This BFF comes with a MicroSD card slot that can address up to 64 GB of... In Stock [Buy Now](https://www.adafruit.com/product/5769) [Related Guides to the Product](https://learn.adafruit.com/products/5769/guides) ![Angled shot of small square audio breakout board.](https://cdn-shop.adafruit.com/640x480/5769-00.jpg) ### or ### Adafruit I2S Amplifier BFF Add-On for QT Py and Xiao [Adafruit I2S Amplifier BFF Add-On for QT Py and Xiao](https://www.adafruit.com/product/5770) Our QT Py boards are a great way to make very small microcontroller projects that pack a ton of power - and now we have a way for you to add an I2S 3 Watt amplifier, for high quality audio playback, that can fit on the back of your miniature dev board. It uses just three GPIO pins that do... In Stock [Buy Now](https://www.adafruit.com/product/5770) [Related Guides to the Product](https://learn.adafruit.com/products/5770/guides) ![Adafruit I2S Amplifier BFF Add-On for QT Py and Xiao.](https://cdn-shop.adafruit.com/640x480/5770-00.jpg) ### Molex PicoBlade 2-pin Cable - 200mm [Molex PicoBlade 2-pin Cable - 200mm](https://www.adafruit.com/product/3922) When 0.1" is too big, and JST PH's too chunky, the ultra-slim "PicoBlade" is a reliable alternative. These are only 1.25mm pitch, but have a nice clicky connection. This cable is nice and long, 200mm in fact. It's got both small form factor (won't take up a lot... In Stock [Buy Now](https://www.adafruit.com/product/3922) [Related Guides to the Product](https://learn.adafruit.com/products/3922/guides) ![Molex Pico Blade 2-pin Cable pigtail ](https://cdn-shop.adafruit.com/640x480/3922-05.jpg) ### Also: ### Mini Oval Speaker - 8 Ohm 1 Watt [Mini Oval Speaker - 8 Ohm 1 Watt](https://www.adafruit.com/product/3923) Hear the good news! This wee speaker is a great addition to any audio project where you need 8 ohm impedance and 1W or less of power. We particularly like this speaker as it is small and comes with nice skinny wires with a connector on the end. It has a handy... In Stock [Buy Now](https://www.adafruit.com/product/3923) [Related Guides to the Product](https://learn.adafruit.com/products/3923/guides) ![Small, black, oval speaker with Pico Blade connector.](https://cdn-shop.adafruit.com/640x480/3923-06.jpg) ### Short Male Header Kit for ItsyBitsy [Short Male Header Kit for ItsyBitsy](https://www.adafruit.com/product/4173) These three  **Short**   **Male Headers**  alone are, well, lonely. But pair them with our [ItsyBitsy boards](https://www.adafruit.com/?q=itsybitsy), and you're in business! These 2.54mm / 0.1" pitch headers are... In Stock [Buy Now](https://www.adafruit.com/product/4173) [Related Guides to the Product](https://learn.adafruit.com/products/4173/guides) ![Angled shot of two short 14-pin plug headers and one short 5-pin plug header.](https://cdn-shop.adafruit.com/640x480/4173-00.jpg) ### Short Female Header Kit for ItsyBitsy [Short Female Header Kit for ItsyBitsy](https://www.adafruit.com/product/4174) These three **Short**   **Female Headers**  alone are, well, lonely. But pair them with any of our [ItsyBitsy](https://www.adafruit.com/?q=itsybitsy) boards, and you're in business! These headers are particularly cute and... In Stock [Buy Now](https://www.adafruit.com/product/4174) [Related Guides to the Product](https://learn.adafruit.com/products/4174/guides) ![Angled shot of two short 14-pin socket headers and one short 5-pin socket headers.](https://cdn-shop.adafruit.com/640x480/4174-00.jpg) - [Next Page](https://learn.adafruit.com/audio-synthesis-with-circuitpython-synthio/synthesizer-fundamentals.md) ## Featured Products ### Adafruit RP2040 Prop-Maker Feather with I2S Audio Amplifier [Adafruit RP2040 Prop-Maker Feather with I2S Audio Amplifier](https://www.adafruit.com/product/5768) The Adafruit Feather series gives you lots of options for a small, portable, rechargeable microcontroller board. By picking a feather and stacking on a FeatherWing you can create advanced projects quickly. One popular combo is our [Feather M4](https://www.adafruit.com/product/3857)... In Stock [Buy Now](https://www.adafruit.com/product/5768) [Related Guides to the Product](https://learn.adafruit.com/products/5768/guides) ### Mono Enclosed Speaker with Plain Wires - 3W 4 Ohm [Mono Enclosed Speaker with Plain Wires - 3W 4 Ohm](https://www.adafruit.com/product/4445) Listen up! This single  2.8" x 1.2" speaker is the perfect addition to any audio project where you need 4 ohm impedance and 3W or less of power. We particularly like these speakers as they are small and enclosed for good audio volume and quality. This speaker _does..._ In Stock [Buy Now](https://www.adafruit.com/product/4445) [Related Guides to the Product](https://learn.adafruit.com/products/4445/guides) ### Adafruit QT Py RP2040 [Adafruit QT Py RP2040](https://www.adafruit.com/product/4900) What a cutie pie! Or is it... a QT Py? This diminutive dev board comes with one of our new favorite chip, the RP2040. It's been made famous in the new [Raspberry Pi Pico](https://www.adafruit.com/pico) _and_ our [Feather...](http://www.adafruit.com/product/4884) Out of Stock [Buy Now](https://www.adafruit.com/product/4900) [Related Guides to the Product](https://learn.adafruit.com/products/4900/guides) ### Adafruit Audio BFF Add-on for QT Py and Xiao [Adafruit Audio BFF Add-on for QT Py and Xiao](https://www.adafruit.com/product/5769) Our QT Py boards are a great way to make very small microcontroller projects that pack a ton of power - and now we have a way for you to turn many QT Py boards into powerful audio play projects that are super small! This BFF comes with a MicroSD card slot that can address up to 64 GB of... In Stock [Buy Now](https://www.adafruit.com/product/5769) [Related Guides to the Product](https://learn.adafruit.com/products/5769/guides) ### Adafruit I2S Amplifier BFF Add-On for QT Py and Xiao [Adafruit I2S Amplifier BFF Add-On for QT Py and Xiao](https://www.adafruit.com/product/5770) Our QT Py boards are a great way to make very small microcontroller projects that pack a ton of power - and now we have a way for you to add an I2S 3 Watt amplifier, for high quality audio playback, that can fit on the back of your miniature dev board. It uses just three GPIO pins that do... In Stock [Buy Now](https://www.adafruit.com/product/5770) [Related Guides to the Product](https://learn.adafruit.com/products/5770/guides) ### Molex PicoBlade 2-pin Cable - 200mm [Molex PicoBlade 2-pin Cable - 200mm](https://www.adafruit.com/product/3922) When 0.1" is too big, and JST PH's too chunky, the ultra-slim "PicoBlade" is a reliable alternative. These are only 1.25mm pitch, but have a nice clicky connection. This cable is nice and long, 200mm in fact. It's got both small form factor (won't take up a lot... In Stock [Buy Now](https://www.adafruit.com/product/3922) [Related Guides to the Product](https://learn.adafruit.com/products/3922/guides) ### Short Male Header Kit for ItsyBitsy [Short Male Header Kit for ItsyBitsy](https://www.adafruit.com/product/4173) These three  **Short**   **Male Headers**  alone are, well, lonely. But pair them with our [ItsyBitsy boards](https://www.adafruit.com/?q=itsybitsy), and you're in business! These 2.54mm / 0.1" pitch headers are... In Stock [Buy Now](https://www.adafruit.com/product/4173) [Related Guides to the Product](https://learn.adafruit.com/products/4173/guides) ### Short Female Header Kit for ItsyBitsy [Short Female Header Kit for ItsyBitsy](https://www.adafruit.com/product/4174) These three **Short**   **Female Headers**  alone are, well, lonely. But pair them with any of our [ItsyBitsy](https://www.adafruit.com/?q=itsybitsy) boards, and you're in business! These headers are particularly cute and... In Stock [Buy Now](https://www.adafruit.com/product/4174) [Related Guides to the Product](https://learn.adafruit.com/products/4174/guides) ## Related Guides - [Adafruit QT Py RP2040](https://learn.adafruit.com/adafruit-qt-py-2040.md) - [Adafruit RP2040 Prop-Maker Feather](https://learn.adafruit.com/adafruit-rp2040-prop-maker-feather.md) - [Adafruit I2S Amplifier BFF](https://learn.adafruit.com/i2s-amplifier-bff.md) - [Adafruit Audio BFF](https://learn.adafruit.com/adafruit-audio-bff.md) - ["Mother of all Demos" USB Keyset](https://learn.adafruit.com/usb-keyset.md) - [Halloween Neon LED Signs](https://learn.adafruit.com/halloween-neon-led-signs.md) - [LED Noodle Lantern](https://learn.adafruit.com/led-noodle-lantern.md) - [Motion Sensor Bat](https://learn.adafruit.com/motion-sensor-bat.md) - [Kitty Toe Bean Keypad with Color TFT](https://learn.adafruit.com/kitty-toe-bean-paw-keypad-color-tct.md) - [IBM PC Keyboard to USB HID with CircuitPython](https://learn.adafruit.com/ibm-pc-keyboard-to-usb-hid-with-circuitpython.md) - [Tyrell Desktop Synthesizer](https://learn.adafruit.com/tyrell-desktop-synthesizer.md) - [Zelda Echoes Of Wisdom Tri Rod](https://learn.adafruit.com/zelda-tri-rod.md) - [Dune Worm Thumper](https://learn.adafruit.com/dune-worm-thumper.md) - [PlayStation Spinner Controller](https://learn.adafruit.com/playstation-spinner-controller.md) - [LED Matrix Alarm Clock](https://learn.adafruit.com/led-matrix-alarm-clock.md) - [Lemon Mechanical Keypad](https://learn.adafruit.com/qtpy-lemon-mechanical-keypad-macropad.md) - [NeoPixel Mini VU Meter](https://learn.adafruit.com/neopixel-mini-vu-meter.md) - [Lightsaber Prop-Maker RP2040](https://learn.adafruit.com/lightsaber-rp2040.md) - [Talking HAL 9000 with RP2040 Prop Maker Feather](https://learn.adafruit.com/hal-9000-rp2040-prop-maker.md)