A Six-Voice Synth Built On The Raspberry Pi

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.

Continue reading “A Six-Voice Synth Built On The Raspberry Pi”

Sync Your Pocket Synth with Ableton

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.

Continue reading “Sync Your Pocket Synth with Ableton”

Building A Wavetable Synth

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.

Continue reading “Building A Wavetable Synth”

Two Guitars, Two Amps, And Three Pole Dual Throw

[Alexbergsland] plays electric guitar. More accurately, he plays two electric guitars, through two amps. Not wanting to plug and unplug guitars from amps and amps from guitars, he designed an AB/XY pedal to select between two different guitars or two different amps with the press of a button.

The usual way of sending a guitar signal to one amp or another is with an A/B pedal that takes one input and switches the output to one jack or another. Similarly, to switch between two inputs, a guitarist would use an A/B pedal. For [Alex]’ application, that’s two pedals that usually sell for $50, and would consequently take up far too much room on a pedalboard. This problem can be solved with a pair of 3PDT footswitches that sell for about $4 each. Add in a few jacks, LEDs, and a nice aluminum enclosure, and [Alex] has something very cool on his hands.

The circuit for this switcher is fairly simple, so long as you can wrap your head around how these footswitches are wired internally. The only other special addition to this build are a trio of LEDs to indicate which output is selected and if both inputs are on. These LEDs are powered by a 9V adapter embedded in the pedalboard, but they’re not really necessary for complete operation of this input and output switcher. The LEDs in this project can be omitted, making this a completely passive pedal to direct signals around guitars and amps.

Bantam-sized Jukebox Reproduction Tops the Fabrication Charts

Restoring a genuine vintage jukebox is a fun project, but finding suitable candidates can be a difficult proposition. Not only can a full-size machine take a huge bite out of your wallet, it can take up a lot of room, too. So a replica miniature jukebox might be just the thing.

We have to admit, at first glance [Allan_D_Murray]’s project seemed like just another juke upgrade. It was only after diving into his very detailed build log that we realized this classic-looking juke is only about 30″ (80 cm) tall. It’s not exactly diminutive, but certainly more compact than the original Wurlitzer 1015 from which it draws its inspiration. But it sure looks like the real thing. Everything is custom made, from the round-top case to the 3D-printed trim pieces, which are painted to look like chrome-plated castings. The guts of the juke are pretty much what you’d expect these days — a PC playing MP3s. But an LCD monitor occupies the place where vinyl records would have lived in the original and displays playlists of the albums available. There’s an original-looking control panel on the front, and there are even bubblers in the lighted pilasters and arches.

Hats off to [Allan] for such a detailed and authentic tribute to a mid-century classic. But if a reproduction just won’t cut it for you, check out this full-size juke with the original electronics.

Continue reading “Bantam-sized Jukebox Reproduction Tops the Fabrication Charts”

Acoustic Accordion Becomes MIDI; Oh the Complexity!

Everyone knows accordions are cool — they look fly, make neat noises, and get your romantic interests all hot and bothered. What isn’t cool is being relegated to acoustics only. How are you going to play a packed stadium or lay down a crystal clear track like that? You could go out and buy an electric accordion, but even low-end models carry a hefty price tag. But, this is Hackaday, and you know we’re going to be telling you about someone who found a better way.

That better way, shown in a build by [Brendan Vavra], was to take an acoustic accordion and convert it to MIDI. The base for his build was a decent full-size acoustic accordion purchased on eBay for just $150. Overall, it was in good mechanical condition, but some of the reeds were out of tune or not working at all. Luckily, that didn’t matter, since he wouldn’t be using them anyway. Don’t be fooled in the demo video below; it sounds like he’s playing the acoustic according but notice he’s not pumping those bellows! However, the bellows isn’t useless either since it can feed data back as a MIDI input.

[Brendan’s] build plan called for an Arduino Mega to be tied to a series of photo-interrupters that would detect button pushes and fire MIDI signals. But, first he had to take the thing apart — no small task, given the complexity of the instrument. The accordion has 120 buttons, and they’re not interchangeable, which means he had to carefully keep track of them as they were disassembled.

Continue reading “Acoustic Accordion Becomes MIDI; Oh the Complexity!”

Annoy Your Neighbors with MIDI Musical Siren

[Yannick], aka [Gigawipf] brings us this (mostly) musical delicacy: a 3D-printed siren that’s driven by a brushless quadcopter motor, and capable of playing (mostly) any music that you’ve got the MIDI score for. This is a fantastic quickie project for any of you out there with a busted quad, or even some spare parts, and a 3D printer. Despite the apparent level of difficulty, this would actually be a great quickie weekend build.

Continue reading “Annoy Your Neighbors with MIDI Musical Siren”