synthesizer

204 Articles

A Six-Voice Synth Built On The Raspberry Pi

February 7, 2017 by 14 Comments

Over the last few decades, audio synthesizers have been less and less real hardware and more and more emulations in software. Now that we have tiny powerful computers that merely sip down the watts, what’s the obvious conclusion? A six-voice polyphonic synthesizer built around the Raspberry Pi.

The exquisitely named ‘S³-6R’ synthesizer is a six-voice phase modulation synthesizer that outputs very high resolution (24-bit and 96 kHz) audio. It’s the product of R-MONO Lab, who have displayed interesting musical devices such as a recorder-based pipe organ in the past. This build is a bit more complex, offering up some amazing sounds, all generated on a Raspberry Pi 3.

While talk of oscillators and filters is great, what’s really interesting here is the keyboard itself. The S³-6R is using the Roland K-25m, a tiny MIDI keyboard meant to serve as a ‘dock’ of sorts for Roland’s recent re-releases of the classic Jupiter and Juno synths. Building a MIDI keyboard is not easy by any stretch of the imagination, and using this little keyboard dock is a cheap way to pipe MIDI notes into any project without a lot of fuss.

Below, you can check out the audio demos of the S³-6R. It’s a real synth and sounds great. We can only hope the software will be uploaded somewhere eventually.

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Sync Your Pocket Synth With Ableton

February 5, 2017 by 17 Comments

The Teenage Engineering Pocket Operators are highly popular devices — pocket-sized synthesizers packed full of exciting sounds and rhythmic options. They’re also remarkably affordable. However, this comes at a cost — they don’t feature MIDI connectivity, so it can be difficult to integrate them into a bigger digital music setup. Never fear, little-scale’s got your back. This Max patch allows you to synchronize an Ableton Link network to your Pocket Operators.

little-scale’s trademark is creating useful software and hardware devices using cheap, off-the-shelf hardware wherever possible. The trick here is a simple Max patch combined with a $2 USB soundcard or Bluetooth audio adapter. It’s all very simple: the Pocket Operators have a variety of sync modes that sync on audio pulses, essentially a click track. They use stereo 3.5mm jacks on board, generally using one channel for the synth’s audio and one channel for receiving sync pulses. It’s a simple job to synthesize suitable sync pulses in Ableton, and then pump them out to the Pocket Operators through the Bluetooth or USB audio output.

The Pocket Operators sync at a rate of 2 PPQN — that’s pulses per quarter note. little-scale says that KORG volcas & monotrons should also work with this patch, as they run at the same rate, but it’s currently untested. If you happen to try this for yourself, let us know if it works for you. Video below the break.

We’ve seen pocket synths on Hackaday before, with this attractive mixer designed for use with KORG Volcas.

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Building A Wavetable Synth

February 5, 2017 by 3 Comments

Every semester at one of [Bruce Land]’s electronics labs at Cornell, students team up, and pitch a few ideas on what they’d like to build for the final project. Invariably, the students will pick what they think is cool. The only thing we know about [Ian], [Joval] and [Balazs] is that one of them is a synth head. How do we know this? They built a programmable, sequenced, wavetable synthesizer for their final project in ECE4760.

First things first — what’s a wavetable synthesizer? It’s not adding, subtracting, and modulating sine, triangle, and square waves. That, we assume, is the domain of the analog senior lab. A wavetable synth isn’t a deep application of a weird reverse FFT — that’s FM synthesis. Wavetable synthesis is simply playing a single waveform — one arbitrary wave — at different speeds. It was popular in the 80s and 90s, so it makes for a great application of modern microcontrollers.

The difficult part of the build was, of course, getting waveforms out of a microcontroller, mixing them, and modulating them. This is a lab course, so a few of the techniques learned earlier in the semester when playing with DTMF tones came in very useful. The microcontroller used in the project is a PIC32, and does all the arithmetic in 32-bit fixed point. Even though the final audio output is at 12-bit resolution, the difference between doing the math at 16-bit and 32-bit was obvious.

A synthesizer isn’t useful unless it has a user interface of some kind, and for this the guys turned to a small TFT display, a few pots, and a couple of buttons. This is a complete GUI to set all the parameters, waveforms, tempo, and notes played by the sequencer. From the video of the project (below), this thing sounds pretty good for a machine that generates bleeps and bloops.

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MIDI DAC For Vintage Synth Hacks

January 9, 2017 by 7 Comments

A lot of classic synthesizers rely on analog control voltages to vary parameters; this is a problem for the modern musician who may want to integrate such hardware with a MIDI setup. For just this problem, [little-scale] has built a MIDI-controllable DAC for generating control voltages.

It’s a simple enough build – a Teensy 2 is used to speak USB MIDI to a laptop. This allows the DAC to be used with just about any modern MIDI capable software. The Teensy then controls a Microchip MCP4922 over SPI to generate the requisite control voltages. [little-scale]’s video covers the basic assembly of the hardware on a breadboard, and goes on to demonstrate its use with a performance using the MIDI DAC to control a Moog Mother 32 synth. [little-scale] has also made the code available, making it easy to spin up your own.

We can see this project being indispensable to electronic musicians working with banks of modular synths, making it much easier to tie them in with automation in their DAW of choice. This isn’t the first MIDI interfacing hack we’ve seen either – check out this setup to interface an iPad to guitar pedals.

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Adding MIDI Out To The Casio PX410R

December 28, 2016 by 12 Comments

Since the 1980s, MIDI has been a great way to send data between electronic musical instruments. Beginning as a modified serial interface running through optoisolaters and DIN sockets, these days, your hardware is more likely to carry its MIDI data over USB instead. This is great if you want to hook up to a computer without a cumbersome interface, but not so great when you want to connect a bunch of instruments to each other.

The Roland Integra 7 is a rack mount synthesizer with classic MIDI ports. [adriangin] wanted to control the synthesizer over MIDI, but their Casio keyboard only had MIDI over USB available. To get around this, [adriangin] set out to add a standard MIDI Out port to the Casio PX410R.

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Gecho Pocket Synth Looper

December 26, 2016 by 2 Comments

[Mario] wrote us with his synthesizer project that’s currently up on Kickstarter. It looks like a good amount of fun to play with, as you can see in the video on the Kickstarter page. But it’s also built to be easily hackable.

On the hardware front, it’s a tiny four-layer board that’s crammed with parts. At the core is an STM32F4 microcontroller and a DAC. Indeed, the build was inspired by other folks’ work on the STM32F4 Discovery dev kit that has been used to make some pretty interesting synthesizer devices. [Mario]’s version adds two stereo headphone outputs, two microphone inputs, two IR reflective distance sensors used as control inputs, some buttons, and a ton of LEDs. And then it makes good use of all of them.

The firmware isn’t open source yet (poke! poke!) but it looks like it’s going to be. On his blog, [Mario] works through an example of adding a drum machine into the existing firmware, so it looks like it’ll be hackable.

Squeezing a lot of DSP functionality out of a single microcontroller is a feat. On a similar chip from a different manufacturer, [Paul Stoffregen]’s Teensy Audio Library could also be made to do a lot of the same things. But the real beauty of the Gecho project is that it has some interesting hardware features already built in and ready to go. It wouldn’t be a bad launching pad for your own musical or audio explorations.

Sporty Cars Making Fake Engine Noise

December 5, 2016 by 124 Comments

Following the monumental emissions-cheating scandal at VW, further horrible revelations demonstrate just how corrupt the modern automotive industry has become: many cars make fake engine noise. And we’re not just talking about those darn sneaky Priuses.

Ford, BMWs, Porsche, and yes, Volkswagen are all doing it, to different degrees. Some of the systems, like the one in the BMW M5, play engine sounds at low volumes through the stereo system. As you’d expect from a BMW, it’s an overly-technological solution: they have built essentially a BMW engine-sound synthesizer that responds to the tachometer and gas pedal data from the car’s data bus. They also let you turn off the “acoustic experience”.

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