Musical Hacks

1375 Articles

Hi-Fi Combines Best Of 60s And 90s Technology

June 7, 2021 by 55 Comments

The 90s were a dark time for audio equipment, literally and figuratively. Essentially the only redeeming quality from the decade of nondescript black plastic boxes was the low cost. Compared to the audio equipment of the 60s, largely produced in high-end enclosures with highly desirable tube amplifiers, the 90s did not offer much when it came to hi-fi stereo sound. However, those cheap black boxes from the 90s turn out to be surprisingly perfect for project enclosures for other amplifier builds, such as this 60s-era tube amp recreation.

This mesh of the best of two distinct decades comes from [Alvenh] and begins by preparing the old enclosure for its new purpose. This means a lot of work fabricating a custom metal face plate for the new amplifier and significantly modifying the remaining case. After the box is complete, the amplifier build began. It uses a tube-based preamp and a solid-state power amplifier since [Alvenh]’s experience suggested that the warm tube sound was generated mostly in the preamp. This means that his design is a hybrid but still preserves the essential qualities of a full tube build.

The build also includes a radio module that has the ability to cover the 2m and 70cm bands popular in ham radio. This module also has been found to have much better audio quality than the standard AM/FM receiver typically used in projects like this. With the radio module added to the custom enclosure, as well as a phono amp and a power supply, [Alvenh] has an excellent audio amplifier in an inexpensive case which preserves the tube sound from the true hi-fi eras of decades past.

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Neural Networks Emulate Any Guitar Pedal For $120

May 30, 2021 by 62 Comments

It’s a well-established fact that a guitarist’s acumen can be accurately gauged by the size of their pedal board- the more stompboxes, the better the player. Why have one box that can do everything when you can have many that do just a few things?

Jokes aside, the idea of replacing an entire pedal collection with a single box is nothing new. Your standard, old-school stompbox is an analog affair, using a combination of filters and amplifiers to achieve a certain sound. Some modern multi-effects processors use software models of older pedals to replicate their sound. These digital pedals have been around since the 90s, but none have been quite like the NeuralPi project. Just released by [GuitarML], the NeuralPi takes about $120 of hardware (including — you guessed it — a Raspberry Pi) and transforms it into the perfect pedal.

The key here, of course, is neural networks. The LSTM at the core of NeuralPi can be trained on any pedal you’ve got laying around to accurately reproduce its sound, and it can even do so with incredibly low latency thanks to Elk Audio OS (which even powers Matt Bellamy’s synth guitar, as used in Muse‘s Simulation Theory World Tour). The result of a trained model is a VST3 plugin, a popular format for describing audio effects.

This isn’t the first time we’ve seen some seriously cool stuff from [GuitarML], and it also hearkens back a bit to some sweet pedal simulation in LTSpice we saw last year. We can’t wait to see this project continue to develop — over time, it would be awesome to see a slick UI, or maybe somebody will design a cool enclosure with some knobs and an honest-to-god pedal for user input!

Thanks to [Mish] for the tip!

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Web Assembly, Music Synthesis, And The Beauty Of Math

May 28, 2021 by 9 Comments

The electronics hobby has changed a lot since the advent of the microprocessor. Before that — and with the lack of large-scale integrated circuits — projects in magazines tended to be either super simple or ultra complex. However, one popular type of project dealt with music synthesis. Fairly simple circuits could combine to make a complex synthesizer so it was sort of the best of both worlds. Nowadays, you are more likely to tackle a music synthesizer in software like [Tim] did when he created Abelton in Web Assembly and C++. Along the way, he learned a lot about the relationship between math and music.

[Tim] covers what he learned about the Nyquist theorem and how to keep synthesis data flowing in real time with buffers. However, there are some problems trying to do all this in a cross-browser context. The AudioWorklet class appears to have widespread support, though, and [Tim] managed to get that working.

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Custom Music Box Cylinder Puts A Spin On Romance

May 25, 2021 by 9 Comments

Music boxes are awesome little mechanical devices. These days, they even make some with slightly more modern tunes, like the Zelda and Star Wars themes.  But they don’t have everything, of course — certainly not that one song from that TV series that [RandomPrototypes]’ girlfriend absolutely adores.

But it’s 2021, and there are options for making your own music box. [RandomPrototypes] could have printed the whole thing, but those don’t sound as good with their plastic combs. Then there’s those paper punch ones, but you have to sit there and crank the thing continuously to hear the song. In the end, [RandomPrototypes] mixed methods and made a custom cylinder that’s playable with a standard music box mechanism.

[RandomPrototypes] started by taking the music box apart to measure the cylinder, and then created a software representation of a cylinder that’s designed to pluck the eighteen notes from low to high rather than play a song. Then he used a Python script to turn it in a 3D model. The slicing preview showed a lot of stops and starts and weak points, so [RandomPrototypes] generated the Gcode directly so that it would print in one continuous spiral and be much stronger.

In order to generate a cylinder with the song his girlfriend likes so much, [RandomPrototypes] printed this scale cylinder and used it to record the notes as a single mp3 and make note of the start times of each note. Finally, he built the new score based on the available notes built into the music box comb. If you want to do this yourself, the code is freely available. The hard part will be choosing a music box mechanism, because they tend to come with a single comb that’s designed to play a specific song. You’ll have to figure out which tune has most or all of the notes you need.

If you don’t mind doing the cranking to listen to the tune, then the paper-punched type of music box is going to be much easier. But why do all that punching yourself, when you could build a machine?

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Smart Guitar Will Practically Play Itself

May 23, 2021 by 25 Comments

Playing the guitar is pretty difficult to do, physically speaking. It requires a lot of force with the fretting hand to produce clear notes, and that means pressing a thin piece of metal against a block of wood until the nerve endings in your fingertips die off and you grow calluses that yearn to be toughened even further. Even if you do get to this point of being broken in, it takes dexterity in both hands to actually make music. Honestly, the guitar is kind of an unwelcoming instrument, even if you don’t have any physical disabilities.

A Russian startup company called Noli Music wants to change all of that. They’re building a guitar that’s playable for everyone, regardless of physical or musical ability. Noli Music was founded by [Denis Goncharov] who has a form of muscular dystrophy. [Denis] has always wanted to rock out to his favorite songs, but struggles to play a standard guitar.

If you can touch the fretboard, it seems, you can whale away on this axe without trouble. It’s made to be easier to play all around. The strings aren’t fully tensioned, so they’re easy to pluck — the site says they only take 1.7oz of force to actuate.

Right now, the guitar is in the prototype stage. But when it’s ready to rock, it will do so a couple of ways. One uses embedded sensors in the fretboard detect finger positions and sound the appropriate note whether you pluck it or simply fret it. In another mode, the finger positions light up to help you learn new songs. The guitar will have a touchscreen interface, and Noli are planning on building a companion app to provide interactive lessons.

We have to wonder just how exactly this will be able to mimic the physics of guitar playing, especially since it’s designed with all players in mind. How satisfied will seasoned players be with this instrument? Can it do pull-offs and hammer-ons? What about slides? Do the sensors respond to bends? And most importantly, will the built-in speaker be loud enough to drown out the string vibrations? It seems to do just fine on that front, as you can see in the video below.

If the built-in speaker didn’t drown out the strings, it could make for some interesting sounds that stray outside the western chromatic scale, much like this LEGO microtonal guitar.

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Making Minty Fresh Music With Markov Chains: The After Eight Step Sequencer

May 18, 2021 by 7 Comments

Step sequencers are fantastic instruments, but they can be a little, well, repetitive. At it’s core, the step sequencer is a pretty simple device: it loops through a series of notes or phrases that are, well, sequentially ordered into steps. The operator can change the steps while the sequencer is looping, but it generally has a repetitive feel, as the musician isn’t likely to erase all of the steps and enter in an entirely new set between phrases.

Enter our old friend machine learning. If we introduce a certain variability on each step of the loop, the instrument can help the musician out a bit here, making the final product a bit more interesting. Such an instrument is exactly what [Charis Cat] set out to make when she created the After Eight Step Sequencer.

The After Eight is an eight-step sequencer that allows the artist to set each note with a series of potentiometers (which are, of course, housed in an After Eight mint tin). The potentiometers are read by an Arduino, which passes MIDI information to a computer running the popular music-oriented visual programming language Max MSP. The software uses a series of Markov Chains to augment the musician’s inputted series of notes, effectively working with the artist to create music. The result is a fantastic piece of music that’s different every time it’s performed. Make sure to check out the video at the end for a fantastic overview of the project (and to hear the After Eight in action, of course)!

[Charis Cat]’s wonderful creation reminds us of some the work [Sara Adkins] has done, blending human performance with complex algorithms. It’s exactly the kind of thing we love to see at Hackaday- the fusion of a musician’s artistic intent with the stochastic unpredictability of a machine learning system to produce something unique.

Thanks to [Chris] for the tip!

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Guitar With Hot-Swappable Pickups Lights Our Fire

May 11, 2021 by 17 Comments

There’s a story that goes something like this: Chet Atkins was playing his guitar when someone remarked, ‘that guitar sounds great!’ Mr. Atkins immediately stopped playing and asked, ‘how does it sound now?’ While it’s true that the sound ultimately comes from you and your attention to expression, we feel that different pickups on the same guitar can sound, well, different from each other.

However, this is merely speculation on our part, because changing pickups is pretty serious surgery, and there’s only one company out there making guitars with hot-swappable pickups. Since their low-end model is out of most people’s price range, [Mike Lyons] took one for the team and decided to build a guitar from scratch to test out various pickups of any size, from lipstick to humbucker. [Mike] can swap them out in under a minute, and doesn’t need any tools to do it.

[Mike] modeled the swapping system on that one company’s way of doing things, because why reinvent the wheel? The pickups are inserted through the back and held in place with magnets and a pair of cleverly-designed printed pieces — one to mount the pickup to, and the other inside the pickup cavity.

As far as actually connecting the things up, [Mike] went with a commercially-available quick-connect pickup solution that uses a mini four-conductor audio plug and jack. The body is based on the Telecaster, while the headstock is more Stratocaster — the perfect visual combination, if you ask us.

We are particularly fond of [Mike]’s list of caveats for this project, especially the requirement that it had to be built using only hand tools and a 3D printer. Although a drill press would have been nice to use, [Mike] did a fantastic job on this guitar. Whether you’re into guitars or not, this is a great story of an awesome build.

What, you don’t even have hand tools? You could just print the whole guitar instead.