Melodio Self Mate

February 12, 2024 by Navarre Bartz 25 Comments

While the proliferation of the smartphone has caused the personal music player (PMP) market to mostly evaporate, there are still those who prefer a standalone device for their music. The Melodio Self-Mate is one such spiritual successor to the iPod.

Music-only devices really benefit from the wheel interface pioneered by Apple, so we still see it in many of the new Open Source PMPs including this one and the Tangara. The Melodio uses the ubiquitous ESP32 for its brains coupled with a TI PCM5102A DAC and TI TPA6130A2 headphone amp for audio. A slider on the side of the device allows you to switch it between mass storage mode and programming mode for the ESP32.

Since this device packs a little more horsepower and connectivity than the original iPods, things like listening to Spotify are doable once assembled, instead of having to completely rebuild the device. Speaking of building, there are only renders on the GitHub, so we’re not sure if this project has made the jump IRL yet. With more people concerned about the distractions of smartphones, maybe this renaissance of open PMPs will lead to a new golden age of music on the go?

Miss the halcyon days of the iPod? They’re easier to hack now than ever, and if you really want to go old school, how about a podcast on a floppy?

Recreating The Quadrophonic Sound Of The 70s

February 6, 2024 by Bryan Cockfield 23 Comments

For plenty of media center PCs, home theaters, and people with a simple TV and a decent audio system, the standard speaker setup now is 5.1 surround sound. Left and right speakers in the front and back, with a center speaker and a subwoofer. But the 5.1 setup wasn’t always the standard (and still isn’t the only standard); after stereo was adopted mid-century, audio engineers wanted more than just two channels and briefly attempted a four-channel system called quadrophonic sound. There’s still some media from the 70s that can be found that is built for this system, such as [Alan]’s collection of 8-track tapes. These tapes are getting along in years, so he built a quadrophonic 8-track replica to keep the experience alive.

The first thing needed for a replica system like this is digital quadrophonic audio files themselves. Since the format died in the late 70s, there’s not a lot available in modern times so [Alan] has a dedicated 8-track player connected to a four-channel audio-to-USB device to digitize his own collection of quadrophonic 8-track tapes. This process is destructive for the decades-old tapes so it is very much necessary.

With the audio files captured, he now needs something to play them back with. A Raspberry Pi is put to the task, but it needs a special sound card in order to play back the four channels simultaneously. To preserve the feel of an antique 8-track player he’s cannibalized parts from three broken players to keep the cassette loading mechanism and track indicator display along with four VU meters for each of the channels. A QR code reader inside the device reads a QR code on the replica 8-track cassettes when they are inserted which prompts the Pi to play the correct audio file, and a series of buttons along with a screen on the front can be used to fast forward, rewind and pause. A solenoid inside the device preserves the “clunk” sound typical of real 8-track players.

As a replica, this player goes to great lengths to preserve the essence of not only the 8-track era, but the brief quadrophonic frenzy of the early and mid 70s. There’s not a lot of activity around quadrophonic sound anymore, but 8-tracks are popular targets for builds and restorations, and a few that go beyond audio including this project that uses one for computer memory instead.

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You Can Use A Crappy Mixer As A Neat Synthesizer

January 25, 2024 by Lewin Day 16 Comments

[Simon the Magpie] found himself in possession of a Behringer mixer that turned up in someone’s garbage. They’re not always the most well-regarded mixers, but [Simon] saw an opportunity to do something a bit different with it. He decided to show us all how you can use a mixer as a synthesizer.

[Simon] actually picked up the “no-input” technique from [Andreij Rublev] and decided to try it out on his own equipment. The basic idea is to use feedback through the mixer to generate tones. To create a feedback loop, connect an auxiliary output on the mixer to one of the mixer’s input channels. The gain on the channel is then increased on the channel to create a great deal of feedback. The mixer’s output is then gently turned up, along with the volume on the channel that has formed the feedback loop. If you’ve hooked things up correctly, you should have some kind of tone feedbacking through the mixer. Want to change the pitch? Easy – just use the mixer’s EQ pots!

It’s pretty easy to get some wild spacey sounds going. Get creative and you can make some crunchy sounds or weird repeating tones if you play with the mixer’s built in effects. Plus, the benefit of a mixer is that it has multiple channels. You can create more feedback loops using the additional channels if you have enough auxiliary sends for the job. Stack them up or weave them together and you can get some wild modulation going.

Who needs a modular synth when you can do all this with a four channel mixer and some cables? Video after the break.

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All I Want For Mr. Christmas Is Some New Music

January 12, 2024 by Kristina Panos 7 Comments

It’s true — you really can find anything (except maybe LEGO) in thrift stores. When [thecowgoesmoo] picked up a Mr. Christmas Symphonium music box one day, they knew they wanted to make it play more than just the standard Christmas and classical fare that ships with the thing.

So they did what any self-respecting hacker would do, and they wrote a MATLAB script that generates new disk silhouette images that they then cut from cardboard with a laser cutter. They also used various other materials like a disposable cutting mat. Really, whatever is lying around that’s stiff enough and able to be cut should work. You know you want to hear Van Halen’s “Jump” coming from a tinkling music box, don’t you? Be sure to check out the video demonstration after the break.

If you don’t want to wait around until a Mr. Christmas lands in your lap, why not make your own hand-cranked music box and accompanying scores?

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Linux Fu: Name That Tune

January 11, 2024 by Al Williams 9 Comments

If you aren’t old enough to remember, the title of this post refers to an old game show where contestants would try to name a tune using the fewest possible notes. What can we say? Entertainment options were sparse before the Internet. However, using audio fingerprinting, computers are very good at pulling this off. The real problem is having a substantial library of fingerprints to compare with. You can probably already do this with your phone, and now you can do it with your Linux computer.

In all fairness, your computer isn’t doing the actual work. In fact, SongRec — the program in question — is just a client for Shazam, a service that can identify many songs. While this is mildly interesting if you use a Linux desktop, we could also see using the same technique with a Raspberry Pi to get some interesting projects. For example, imagine identifying a song playing and adjusting mood lighting to match. A robot that could display song information could be the hit of a nerdy party.

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Building A Loop Station With An RP2040

January 11, 2024 by Lewin Day 9 Comments

Loop stations are neat things, able to replay one or more loops of audio over and over again while you perform over the top of them. Musicians like [Marc Rebillet], [Reinhardt Buhr], and [Dub FX] have made careers out of this style of performance. [Yaqi Gao], [Xiaoyu Liang] and [Alina Wang] decided to build a loop station of their own, using the popular RP2040 chip.

At its simplest, a loop station must take in audio, record it, and then play it back. Generally, it can do this with several tracks and mix them together, while also mixing in the incoming audio as well. The group achieved this by inputting a guitar signal to the chip via an amplifier and the onboard analog-to-digital converter. The audio can be recorded as desired, and then played back via an external digital-to-analog converter. Live audio from the guitar is also passed through to allow performing over the recorded sound. The group also used an external half-megabyte FRAM chip to allow storing additional audio sample data, which can be trucked out over serial and saved.

It’s not the cleanest loop station in the world, with a relatively low sample rate causing some artifacts. Regardless, it definitely works, and taught the group plenty about working with digital audio in the process. For that reason alone, we’d call it a success.

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There Are Stradi-various Ways To Make A Violin, And This Is One

January 8, 2024 by Kristina Panos 14 Comments

We’ve always said that if we had enough money, we’d have a large room that housed every musical instrument we’ve ever been even mildly interested in. While that dream may never come to pass, it would be far more likely to happen if many of the instruments could be 3D-printed, like this electric violin.

We really like this compact design, which mimics a headless guitar with the tuning pegs down by the bridge. [Carmensr] started with a model on Thingiverse, which uses violin strings wound around electric guitar tuners instead of wooden friction pegs. To further the guitar comparison, the three-piece neck contains a truss rod of sorts.

So how does it work, though? The magic is in the special bridge, which contains a piezo element. The bridge picks up the strings’ vibrations and sends them to a little pre-amplifier, which creates a signal that can then be used by a program like Audacity or connected directly to a speaker. Be sure to give it a listen in the video after the break.

Of course, there’s no reason not to design and print acoustic violins. It would be fun to experiment with different filaments for different sounds.

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