How A Vintage Toy Piano Was Transformed Into A Polyphonic Digital Synthesizer

Lead Software Developer at Modal Electronics and author at AskAudio Magazine by day, Liam Lacey is a freelance maker and creative technologist by night (well, outside of working hours, but you get my point). 

Not content having transformed a vintage toy piano into a MIDI controller at MIDI Hack in May 2015 (and having received a swish prize for doing so), Liam is back and taking his music hacking skills to the next level and beyond in the creation of his Vintage Toy Synthesizer.

The Vintage Toy Synthesizer in all its glory.

The humble vintage wooden toy piano has now been turned into a standalone polyphonic digital synthesizer. This DIY hardware synth project is being submitted to the Element14 Music Tech design Challenge. Oh, and the aesthetic design itself is pretty damn cool too.

Overview Video of the Vintage Toy Synthesizer:

Sound Demos:

Note: The Macbook is ONLY being used to change patches. All sounds are coming from the Vintage Toy Synth.

Using Vintage Toy Synthesizer as a MIDI Controller:

The Brain of the synth is running on a BeagleBone Black board running Linux. Liam developed the voice engine using the C++ audio DSP library Maximilian, and the keyboard mechanism uses homemade pressure sensors made out of Velostat. And, in true music hacker-style, this polyphonic digital synth is completely open-source.

Synth Specs

• Primary features of the synth:
• 2-voice digital synthesiser with true polyphony
• 5 oscillators with dedicated waveforms
• State-Varible-Filter with independent LP, HP, BP and Notch mix controls
• Amplitude and Filter ADSR envelopes
• Two modulation sources (LFO and keyboard velocity) with three destinations, each with independent bipolar depth controls
• Digital distortion FX
• Changeable scales on the keyboard
• Vintage’ parameter for replicating old/broken analogue synth voices
• Full MIDI I/O integration
• Polyphonic Aftertouch expression (MIDI-out only)
• Charming miniature grand piano form

We asked Liam what the main challenges were in converting the toy piano into a fully fledged digital synthesizer. He explains “I only consider myself a hacker or tinkerer when it comes to electronics, so the main challenge when undertaking this project was having to learn more advanced electronics in order to get the synth working in the way I wanted it to, and often not understanding why the electronics would go wrong from time to time.”

A peek inside the Vintage Toy Synthesizer.

And for those who’d love to following a similar path and create their own music hardware but might not know where to start? Liam suggests, “There are so many hardware maker platforms (e.g BeagleBone, Arduino, Teensy, Raspberry Pi) and software toolkits (Max/MSP, PureData, JUCE) designed for allowing beginners to develop audio software and hardware, with an abundance of books and online tutorials teaching how to use them, so if you have an idea for something you want to create there is most likely an easy and affordable way to make it happen.”

Stay tuned to Ask.Audio for a follow up tutorial-article in the future where Liam will go into more depth on how he created the digital synth. Before then, the Vintage Toy Synthesizer will be entered into the Element14 Music Tech Design Challenge. Good luck Liam!