synthesizer

201 Articles

Tulip Is A Micropython Synth Workstation, In An ESP32

August 8, 2024 by 6 Comments

We’re not sure exactly what Tulip is, because it’s so many things all at once. It’s a music-making environment that’s programmable in Python, runs on your big computer or on an ESP32-S3, and comes complete with some nice sounding synth engines, a sequencer, and a drum machine all built in. It’s like your dream late-1980s synthesizer workstation, but running on a dev board that you can get for a song.

And because Tulip is made of open-source software and hardware, you can extend the heck out of it. For instance, as demonstrated in this video by [Floyd Steinberg], you can turn it into a fully contained portable device by adding a touchscreen. That incarnation is available from Makerfabs, and it’s a bargain, especially considering that the developer [Brian Whitman] gets some of the proceeds. Or, because it’s written in portable Python, you can run it on your desktop computer for free.

The most interesting part of Tulip for us, as programmer-musicians, is that it boots up into a Micrypython REPL. This is a synth workstation with a command-line prompt as its primary interface. It has an always-running main loop, and you make music by writing functions that register as callbacks with the main loop. If you were fast, you could probably live-code up something pretty interesting. Or maybe it wants to be extended into a physical musical instrument by taking in triggers from the ESP32’s GPIOs? Oh, and did we mention it sends MIDI out just as happily as it takes it in? What can’t Tulip do?

We’ve seen some pretty neat minimalist music-making devices lately, but in a sense Tulip takes the cake: it’s essentially almost entirely software. The various hardware incarnations are just possibilities, and because it’s all open and extremely portable, you can freely choose among them. We really like the design and sound of the AMY software synthesizer engine that powers the Tulip, and we’re sure that more synthesizer models will be written for it. This is a music project that you want to keep your eyes on in the future.

The Last Instrument To Get Auto-Tuned

July 30, 2024 by 14 Comments

Various decades have their musical signature, like the excessive use of synthesizers and hairspray in the 1980s pop music scene. Likewise, the early 2010s was marked by a fairly extreme use of autotune, a technology that allows sounds, especially vocals, to be shifted to precise pitches regardless of the pitch of the original source. In this dark era, a wide swath of instruments and voices on the charts were auto-tuned at some point, although we don’t remember this iconic instrument ever being featured among the annals of pitch-shifted pop music.

The auto-tuned kazoo created by [Guy Dupont] does its pitch corrections on-the-fly thanks to a built-in ESP-32-S3 microcontroller which, through a microphone inside the kazoo, listens for note of the musician’s hum and corrects it to the closest correctly pitched note. Once it identifies the note it outputs a kazoo-like pitch-corrected note from a small speaker, also hidden inside the instrument. It does this fast enough for live performances using the YIN fundamental frequency estimation algorithm. Not only can the kazoo be played directly, but thanks to the implementation of MIDI it can be used to control other synthesizers or be played through other means as a stand-alone synthesizer.

Much like the 80s, where the use of synthesizers relaxed from excessive use on nearly every instrument on every track throughout the decade to a more restrained use as the decade faded, so has autotune been toned down in most music to be more subtly applied. But like our enjoyment of heavily synthesized tunes outside the 80s like those by Daft Punk or The Weeknd, we can also appreciate something heavily auto-tuned outside of the 2010s like a stylized kazoo or a T-Pain-style guitar effects pedal.

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MIDI Controller In A Cubic Inch

July 27, 2024 by 2 Comments

MIDI as a standard has opened up a huge world to any musician willing to use a computer to generate or enhance their playing and recording. Since the 80s, it has it has revolutionized the way music is produced and performed, allowing for seamless integration of digital instruments, automation of complex sequences, and unprecedented control over everything from production to editing. It has also resulted in a number of musical instruments that probably wouldn’t be possible without electronic help, like this MIDI instrument which might be the world’s smallest.

Fitting into a cubic inch of space, the tiny instrument’s volume is mostly taken up by the MIDI connector itself which was perhaps an acceptable size by 1980s standards but seems rather bulky today. A two-layer PCB split into three sections sandwiches the connector in place and boasts an ATtiny85 microcontroller and all the associated electronics needed to implement MIDI. Small threaded screws hold the platform together and provide each layer with a common ground. Four small pushbuttons at the top of the device act as the instrument’s keys.

The project’s creator (and Hackaday alum!) [Jeremy Cook] has it set up to play notes from a piano right now, but has also made the source code available so that any musical action can be programmed onto these buttons. Flexibility is perhaps MIDI’s greatest strength and why the standard has lasted for decades now, as it makes it fairly straightforward to build more comprehensive, easy-to-learn musical instruments or even musical instruments out of retro video game systems.

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Raspberry Pi Pico Becomes MIDI-Compatible Synth

December 22, 2023 by 13 Comments

ECE 4760 is a microcontroller course that runs at Cornell every year, and it gives students a wide remit to pursue various kinds of microcontroller projects. [Pelham Bergesen] took the class and built himself a MIDI-controllable synthesizer out of a Raspberry Pi Pico.

[Pelham] coded a library to parse MIDI messages on the Pico, with the microcontroller’s UART charged with receiving the input data. MIDI is basically just serial at a baud rate of 31.25k, with a set message structure, after all. From there, the Pico takes the note data and plays the relevant frequencies by synthesizing square waves using a PWM output. A second PWM channel can also be blended with the first to generate more complex tones.  The synthesizer is designed to be used with a source of MIDI note data such as a keyboard controller; [Pelham] demonstrates the project in use with a Roland JD-XI. It’s a fairly basic synthesizer, but [Pelham] does a good job of explaining all the steps required to get this far. If you’ve never done an audio or MIDI project before, you might find his guide very helpful for the way it steps through the basics.

[Pelham] didn’t get to implement fancier features like direct digital synthesis (DDS) or analog audio effects before the class closed out. However, that would be an excellent project for anyone else developing their own Pico synthesizer. If you whip up something that sounds good, or even just interesting, be sure to notify us on the tipsline. Video after the break.

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The Reverse Oscilloscope

September 25, 2023 by 17 Comments

Usually, an oscilloscope lets you visualize what a signal looks like. [Mitxela]’s reverse oscilloscope lets you set what you want an audio waveform to look like, and it will produce it. You can see the box in the video below.

According to [Mitxela] part of the difficulty in building something like this is making the controls manageable for mere mortals. We really like the slider approach, which seems pretty obvious, but some other controls are a bit more subtle. For example, the interpolation control can create a squarish wave or a smooth waveform, or anything in between.

This is sort of an artistic take on an arbitrary waveform generator but with a discrete-panel user interface. The device contains a Teensy, a Raspberry PI Pico, a 16-bit ADC, and an external DAC. The Pico is little more than an I/O controller, reading the user interface and transmitting it on a serial port.

The outside construction looks excellent (we assume the tape is temporary). The inside is a bit messier, but still nicely done. There are many photos of the construction and details of problems along the way with 12-bit ADCs and power supply experiments.

Of course, if you don’t need the user interface, you can go crazy with waveform generation. We did our own similar project, but you could draw your waveforms on the PC instead of sliders.

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Mangle Videos With RecurBOY And A Raspberry Pi Zero

May 28, 2023 by 6 Comments

You used to need a lot of equipment to be a video DJ. Now you can do it all with a Raspberry Pi Zero and [cyberboy666]’s recurBOY. And if you missed out on the 1970’s video-editing psychedelia, now’s your chance to catch up – recurBOY is a modern video synth with all of the bells and whistles, and it’ll fit in your pocket. Check out [cyberboy666]’s demo video if you don’t yet know what you’re getting into. (Embedded below.)

RecurBOY has four modes: video, shader, effects, and external input, and each of these is significantly cooler than the previous. Video mode plays videos straight off of the SD card through the recurBOY’s composite video out. Shader mode lets you program your own shaders using the GLES shader dialect for resource-constrained devices. And this is where the various knobs and buttons come in. You can program the various shader routines to read any of the pots as input, allowing you to tweak the graphics demos on the fly.

Effects mode overlays your shaders on the video that’s playing, and external mode allows you to plug in a USB video capture card or a webcam so you can do all that same mangling with a live camera feed. And these two modes are where it gets awesome. The shader effects in the demo video cover all of the analog classics – including bloom and RGB separation – but also some distinctly digital effects. And again, you can tweak them all live with the knobs. Or plug in a MIDI controller and control it all externally. What hasn’t he thought of?

Old school analog video effects are really fun, and recurBOY brings them to you with the flexibility of modern shader coding. What’s not to love? If you want to see the pinnacle of the pre-digital era, that would be the Scanimate. For a video synth that integrates with your audio synth, check out Hypno. And if glitching the video is more your style, you can hijack the RAM of a VGA/composite converter.

Trippy, man!

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Compose Any Song With Twelve Buttons

March 29, 2023 by 14 Comments

Limitations placed on any creative process often paradoxically create an environment in which creativity flourishes. A simple overview of modern pop, rock, or country music illustrates this principle quite readily. A bulk of these songs are built around a very small subset of music theory, often varying no more than the key or the lyrics. Somehow, almost all modern popular music exists within this tiny realm. [DeckerEgo] may have had this idea in mind when he created this tiny MIDI device which allows the creation of complex musical scores using a keyboard with only 12 buttons.

The instrument is based around the Adafruit MacroPad, which is itself built on the RP2040 chip. As a MIDI device, it needs to be connected to a computer running software which can support MIDI instruments, but once its assembled and given its firmware, it’s ready to rock. A musician can select one of any number of musical scales to operate within, and the 12 keys on the pad are mapped to the 12 chromatic notes within that scale. It can also be used to generate drum tracks or other backing tracks to loop before being used to create melodies as well.

[DeckerEgo] took a bit of inspiration from an even simpler macro pad we featured before which is based around the idea that a shockingly high number of songs use the same four chords. His macro pad includes creation of chord progressions as well, but expands on that idea to make more complete compositions possible. And, for those looking to build their own or expand on this project, he has also made all of the source code available on his GitHub page.

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