Taking Cues From A Gramophone To Make A Better Marble Music Machine

February 25, 2025 by Donald Papp 4 Comments

[Martin] of [Wintergatan] is on a quest to create the ultimate human-powered, modern marble music machine. His fearless mechanical exploration and engineering work, combined with considerable musical talent, has been an ongoing delight as he continually refines his designs. We’d like to highlight this older video in which he demonstrates how to dynamically regulate the speed of a human-cranked music machine by taking inspiration from gramophones: he uses a flyball governor (or centrifugal governor).

The faster the shaft turns, the harder the disk brake is applied.

These devices are a type of mechanical feedback system that was invented back in the 17th century but really took off once applied to steam engines. Here’s how they work: weights are connected to a shaft with a hinged assembly. The faster the shaft spins, the more the weights move outward due to centrifugal force. This movement is used to trigger some regulatory action, creating a feedback loop. In a steam engine, the regulator adjusts a valve which keeps the engine within a certain speed range. In a gramophone it works a wee bit differently, and this is the system [Wintergatan] uses.

To help keep the speed of his music machine within a certain narrow range, instead of turning a valve the flyball governor moves a large disk brake. The faster the shaft spins, the harder the brake is applied. Watch it in action in the video (embedded below) which shows [Wintergatan]’s prototype, demonstrating how effective it is.

[Wintergatan]’s marble machine started out great and has only gotten better over the years, with [Martin] tirelessly documenting his improvements on everything. After all, when every note is the product of multiple physical processes that must synchronize flawlessly, it makes sense to spend time doing things like designing the best method of dropping balls.

One final note: if you are the type of person to find yourself interested and engaged by these sorts of systems and their relation to obtaining better results and tighter tolerances, we have a great book recommendation for you.

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Hearing What The Bats Hear

February 11, 2025 by Elliot Williams 9 Comments

[Iftah] has been exploring the sounds beyond what we can hear, recording ultrasound and pitching it down. He made a short video on the practice, and it’s like a whole new world of sounds exists just outside of our hearing.

For instance, a dropped toothpick sounds like you’ve just dropped a piece of lumber, a broken lightbulb sounds like a shattered window, and a blackbird sounds like a blue whale. Besides simply sounding super, [Iftah] speculates that there’s some regularity here: that as you slow down the sound it sounds like it came from sources that are physically bigger. He follows this up in a second video, but if you just think about the basic physics, it makes sense.

If you’re interested in recording your own ultrasound, there are a bunch of options on the market. With modern audio processors running up to 192 kHz or even 384 kHz out of the box, all that’s missing is the high-frequency-capable microphone. Those aren’t unobtainable anymore either with many MEMS mics performing well above their rated frequency response specs. Recording ultrasound sounds like a fun and not-too-expensive project to us!

Of course, most of the ultrasound recording we’ve seen has been about the bats. Check out the Pipistrelle or this pair of DIY bat detectors for some good background. But after watching [Iftah]’s video, we’re no longer convinced that the cute little insectivores are the coolest thing going on in the ultrasound.

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Cyberbass Brings Bass Guitar To Modern Era

February 4, 2025 by Bryan Cockfield 19 Comments

For better or worse, the fundamental design of guitars has remained familiar since they electrified around a century ago. A few strings, a fretboard, and a body of some sort will get you most of the way there for an acoustic guitar, with the addition of electromagnetic pickups and wiring for electric variants. However, technology has advanced rapidly in the last 100 years outside the musical world, so if you want to see what possibilities lie ahead for modernizing guitars take a look at the Cyberbass created by [Matteo].

The guitar starts its life as many guitars do: with a block of wood. One of the design goals was to be able to use simple tools to build the guitar, so the shape of the instrument was honed with a Japanese hacksaw and the locations for the pickups and other electronics were carved out with chisels.

The neck of the guitar was outsourced since they take some pretty specialized tools to build, so simply bolting it to the body takes care of that part of the build, but [Matteo] had a few false starts setting the bridge in the exact location it needed to be.

Luckily he was able to repair the body and move the bridge. With the core of the guitar ready, it was on to paint and then to its custom electronics. [Matteo] built in not only a set of pickups and other common electric guitar parts but also integrated a synth pedal into the body as well as including a chromatic tuner.

With everything assembled and a few finishing touches added including a custom-engraved metal signature plate, the Cyberbass is ready to go on tour. [Matteo] learned a lot about guitar building in general, as well as a few things about electronics relating to musical instruments (including how expensive tuners work just as well as cheap ones).

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Cassette Tape Plays MP3s

January 6, 2025 by Bryan Cockfield 65 Comments

Cassette tapes were a major way of listening to (and recording) music througout the 1980s and 1990s and were in every hi-fi stereo, boom box, and passenger vehicle of the era. Their decline was largely as a result of improvements in CD technology and the rise of the MP3 player, and as a result we live in a world largely absent of this once-ubiquitous technology. There are still a few places where these devices crop up, and thanks to some modern technology their capabilities as a music playback device can be greatly enhanced.

The build starts, as one might expect, by disassembling the cassette and removing the magnetic tape from the plastic casing. With the interior of the cassette empty it’s capable of holding a small battery, USB-C battery charger, and a Bluetooth module. The head of an old tape deck can be wired to the audio output of the Bluetooth module and then put back in place in the housing in place of the old tape. With the cassette casing reassembled, there’s nothing left to do but pair it to a smartphone or other music-playing device and push play on the nearest tape deck.

As smartphones continue to lose their 3.5 mm headphone jacks, builds like this can keep lots of older stereos relevant and usable again, including for those of us still driving older vehicles that have functioning tape decks. Of course, if you’re driving a classic antique auto with a tape technology even older than the compact cassette, there are still a few Bluetooth-enabled options for you as well.

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The Math Behind The Music Of The 80s

December 11, 2024 by Bryan Cockfield 51 Comments

Although there might have been other music produced or recorded in the 1980s, we may never know of its existence due to the cacophony of all of the various keytars, drum machines, and other synthesized music playing nonstop throughout the decade. There was perhaps no more responsible synthesizer than the Yamaha DX7 either; it nearly single-handedly ushered in the synth pop era. There had been other ways of producing similar sounds before but none were as unique as this keyboard, and for ways beyond just its sound as [Kevin] describes in this write-up.

Part of the reason the DX7 was so revolutionary was that it was among the first accessible synthesizers that was fully digital, meaning could play more than one note at a time since expensive analog circuitry didn’t need to be replicated for multiple keys. But it also generated its tones by using frequency modulation of sine waves in a way that allowed many signals to be combined to form different sounds. While most popular musicians of the 80s used one of the preset sounds of the synthesizer, it could produce an incredible range of diverse sounds if the musician was willing to dig a bit into the programming of this unique instrument.

There were of course other reasons this synthesizer took off. It was incredibly robust, allowing a musician to reliably carry it from show to show without much worry, and it also stood on the shoulders of giants since musicians had been experimenting with various other types of synthesizers for the previous few decades. And perhaps it was at the right place and time for the culture as well. For a look at the goings on inside the chip that powered the device, [Ken Shirriff] did a deep dive into one a few years ago.

Minichord Wants To Help You Find Rad Chord Progressions

November 28, 2024 by Lewin Day 8 Comments

If you’re good at music theory, you can probably find all the chords and progressions you need just by using your fingers and a suitable instrument. For a lot of musicians, though, remembering huge banks of chords can be difficult, and experimenting with combinations can quickly become tedious and tiring. Enter the minichord, a tiny version of the Omnichord synth designed by [Benjamin] that offers to help out by putting all the chords you need a mere button press away.

The minichord is based around the Teensy 4.0, a capable microcontroller platform if ever there was one. It’s paired with a bunch of tactile buttons which are used to tell the Teensy which chord you desire to play. Various combinations of buttons can be used to play more advanced chords, too. There are potentiometers on board as well for volume control, as well as a touch pad for “strumming” arpeggios and other fine control tasks. An online interface allows modifying the presets onboard, too.

[Benjamin] hopes to get the minichord into production; it’s currently in a Seeedstudio competition that could see that happen, based on likes on the project video. The minichord isn’t the only player in this space, of course. The Orchard synth has been making similar waves this week. We’ve seen [Benjamin’s] work before, too. Video after the break. Continue reading “Minichord Wants To Help You Find Rad Chord Progressions” →

Laser Sound Visualizations Are Not Hard To Make

November 13, 2024 by Lewin Day 17 Comments

You might think that visualizing music with lasers would be a complicated and difficult affair. In fact, it’s remarkably simple if you want it to be, and [byte_thrasher] shows us just how easy it can be.

At heart, what you’re trying to do is make a laser trace out waveforms of the music you’re listening to, right? So you just need a way to move the laser’s beam along with the sound waves from whatever you’re listening to. You might be thinking about putting a laser on the head of a servo-operated platform fed movement instructions from a digital music file, but you’d be way over-complicating things. You already have something that moves with the music you play — a speaker!

[byte_thrasher’s] concept is simple. Get a Bluetooth speaker, and stick it in a bowl. Cover the bowl with a flexible membrane, like plastic wrap. Stick a small piece of mirror on the plastic. When you play music with the speaker, the mirror will vibrate and move in turn. All you then have to do is aim a safe laser in a safe direction such that it bounces off the mirror and projects on to a surface. Then, the laser will dance with your tunes, and it’ll probably look pretty cool!

We’ve seen some beautiful laser visual effects before, too. Just be careful and keep your power levels safe and your beams pointing where they should be.

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