DIY Analog Synth Looks Like Fun

December 10, 2021 by Rich Hawkes 11 Comments

The relative ease of building the individual components that make up an analog synth make it very tempting to DIY your own. That’s what [Albert Nyström] did and the result is this great looking, and great sounding, analog synth.

The VCOs in his monosynth are based around the AS3340 VCO chip, which is a clone of the Curtis Electromusic Specialties‘ CEM3340 chip (used in machines such as the Oberheim OB-Xa, the Roland Jupiter-6, and the Sequential Circuits Prophet-5 among others.) The voltage controlled filters are based on Moritz Klein’s VACTROL based VCF circuits, and the envelopes based on Thomas Henry’s 555 envelope circuits (Google searches will dig those up pretty quickly, as well as schematics for builds using the CEM chip.) Finally, the keyboard is a donor from an Arturia Keystep. While there are no step-by-step build instructions, or a schematic, we do have some info about the instrument. As you can see from some of the gut shots, it should be fairly easy to figure how [Albert] has put everything together. Or not.

Even if the internals are a bit wild, the end result is a great looking monophonic synth that does pretty much everything you’d need. If you feel the itch to wire a bunch of components together and make one yourself, there are messier ways to go about it. Or maybe you’d prefer to go the digital route? Either way, synths are a ton of fun to build and to play.

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Modern Features In Classic Radio

December 7, 2021 by Bryan Cockfield 53 Comments

As consumer electronics companies chase profits on tighter and tighter margins, it seems like quality is continually harder to find for most average consumer-grade products. Luckily, we don’t have to hunt through product reviews to find well-built merchandise since we have the benefit of survivorship bias to help us identify quality products from the past that have already withstood the test of time. [Tom] has forever been fond of this particular Sony TV/radio combo from the ’70s so he finally found one and set about modernizing it in a few key ways.

Among the modifications to this 1978 Sony FX-300 include the addition of a modern color display, Bluetooth, an upgraded FM radio, and a microphone. At the center of all of this new hardware is a Teensy 4 which [Tom] has found to be quite powerful and has enough capabilities to process the audio that’s being played in order to make visual representations of the sound on the screen. He also implemented a bitcrusher filter and integrated it into the controls on the original hardware. He’s using an optimized version of this library to cram all of that processing ability into such a small chip, and the integration of all this new hardware is so polished that it looks like it could be an original Sony stereo from the modern era.

While some may complain about restomod-type builds like this, we don’t really see any need to be arbitrarily or absolutely faithful to bygone eras even if the original hardware was working properly in the first place. What works is taking the proven technology of the past and augmenting it with modern features to enjoy the best of both worlds. Much like this hi-fi stereo which blends the styles and technology of the 90s with that of the 60s in an equally impressive way.

Guitar Pickguard Adds MIDI Capabilities

December 6, 2021 by Bryan Cockfield 1 Comment

For a standard that has been in use since the 1980s, MIDI is still one of the most dominant forces on the musical scene even today. It’s fast, flexible, and offers a standard recognized industry-wide over many different types of electronic instruments. Even things which aren’t instruments can be turned into musical devices like the infamous banana keyboard via the magic of MIDI, and it also allows augmentation of standard instruments with other capabilities like this guitar with a MIDI interface built into the pick guard.

[Ezra] is the creator of this unique musical instrument which adds quite a few capabilities to his guitar. The setup is fairly straightforward: twelve wires run to the pick guard which are set up as capacitive sensors and correspond with a note on the chromatic scale. Instead of using touchpads, using wires allows him to bend away the “notes” that he doesn’t need for any particular piece of music. The wires are tied back to an Adafruit Feather 32u4 microcontroller behind the neck of the guitar which also has a few selectors for changing the way that the device creates tones. He can set the interface to emit single notes or continuously play notes, change the style, can change their octave, and plenty of other features as well.

One of the goals of this project was to increase a guitar player’s versatility when doing live performances, and we would have to agree that this gives a musician a much wider range of abilities without otherwise needing a lot of complex or expensive equipment on stage. We’ve seen a few other MIDI-based builds focused on live performances lately, too, like this one which allows a band to stay in sync with each other.

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Bass Guitar Gets Shapeshifting Pickups

December 5, 2021 by Bryan Cockfield 19 Comments

Electric guitars were the hip new thing back in the mid-century. The electrification of the common and portable guitar opened up a lot of avenues in terms of sound and technique. Specifically, the use of the pickup, an electromagnetic device which converts the vibrations of the guitar strings into electrical signals, increased the number of ways that a musician can alter the guitar’s sound on-the-fly. Some guitars have several rows of pickups which can be used in any number of ways, but this custom guitar has a single pickup which can be moved around the guitar’s body instead.

[Breno] was gifted this Dolphin bass guitar to start learning after years of playing a regular guitar, and while they aren’t known for high-quality instruments this guitar seemed to play and sound well enough to attempt this modification. First, a hole had to be cut all the way through the guitar’s body in order to accommodate the build. The pickup for this guitar is then mounted on two rods which allow it to move in various positions along the strings, and a second set of adjustments can be made to bring the pickups closer or further away from the strings. Some additional custom circuitry was added to control it and also to handle the volume and tone knobs, and while this was being added [Breno] and his friend [Arthur] decided this would be a great time to build some effects into the guitar’s now-custom electronics as well.

While this was largely a project for [Breno] to understand in greater depth the effect of moving the pickups around an electric guitar, the finished product looks ready to play some live shows. The addition of some extras like the effects really adds some punch to this guitar and it looks to be completely original. The nearest thing we could find is this guitar which uses hot-swappable pickups but even those are mounted in fixed locations.

Get Down To Some African Tunes With This HomeBrew Synth

December 5, 2021 by Dave Rowntree 9 Comments

~~South African~~ [Afrorack] claims to have built the first home-built modular synthesiser in Africa. Whilst we can’t be sure of this (and to be frank, it doesn’t actually matter) what we can be sure of is that the latest additions to this rig sound pretty rad. (video, embedded below) There really isn’t much doubt that the African nations are the kings of rhythm, and that living in the less well-to-do areas you need to have a certain resourcefulness to use the materials around you. It’s not like you can just pop down to the local electronics store for a missing part, even if you had the funds for it.

The modular synth looks pretty nice, rough and ready like a real homebrew, and the use of an oil can as a bass drum and rice in a plastic skiff as an instrument might look crude, but sound pretty good. All three additions to the rig are simple spring-loaded solenoid affairs, but since off the shelf stuff is an expensive luxury, hand wound coils were in order. With a bobbin formed with a metal rod and two suitably trimmed fanta bottle lids, a wire spool holder sitting on what looks like a cake stand, a drill powered coil winder was constructed. We did smirk a little when in an early shot, wire was guided by hand, which was rapidly followed by an adjustment to guiding with a rag. Darn friction burns! We’re watching this with interest to see what the next additions will be, but for now, just sit back and nerd out to some sick African techno tunes!

Want to see a mess-o-wires turn into something meaningful? Got some Game Boys lying around needing something to do? How about a chiptune synth?

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Generate Fully Parametric, 3D-Printable Speaker Enclosures

November 28, 2021 by Donald Papp 9 Comments

Having the right speaker enclosure can make a big difference to sound quality, so it’s no surprise that customizable ones are a common project for those who treat sound seriously. In that vein, [zx82net]’s Universal Speaker Box aims to give one everything they need to craft the perfect enclosure.

The parts can be 3D-printed, but the design ensures that the front and back panels are flat, so one can use wood or some other material for those depending on preference and appearance. The assembly is screwed together using six M3 bolts per side with optional heat-set inserts, but it’s entirely possible to simply glue the unit together if preferred.

One thing that makes this design a bit more broadly useful is that [zx82net] not only provides the parametric design file for Fusion360, but also includes STEP format CAD files, and a small number of pre-configured assemblies for a few commonly available speaker drivers: the Dayton Audio DMA70-4, ND91-4, and the TCP115-4. Not enough for you? Check out [zx82net]’s collection of ready-to-rock enclosures in a variety of designs and configurations; there’s bound to be something to appeal to just about anyone.

[via Reddit]

LEDs display different pitches in a sunburst pattern

Spiral Music Visualization

November 26, 2021 by Mike Szczys 6 Comments

Displaying notes live as they are being played can be a really powerful learning tool, but it’s usually used to learn how to play a specific instrument. This take on the topic is actually a neat way to learn more about music theory — how pitches work together to build the sounds that we hear. The visual tack chosen arranges each of 12 notes into a spiral. As you continue to go up the scale through more octaves, pitches that share the same name line up into a line like a ray projecting out from the sun. So there are 12 rays for the notes in the scale: C, C#/D♭, D, D#/E♭,F, etc.

[mechatronicsguy] built it a few years back but just now got around to documenting it, and we’re sure glad he did. The layout of notes at first looks just like a colorful visualization. But as he mentions in his description, this assigns a shape to each different type of cord. A major cord will have the same shape whether it is played with C, G#, B♭, or any other note as the root. The shape simply rotates around the axis based on that root note. Higher octaves will be shown further out on the radius, but the chord shape will still be the same. Minor, augmented, even modal chords and those with added pitches all have their own unique shape on the display.

You get the best understanding of the visualization by looking at the Python-rendered version in the video below. It’s a nice touch that notes turn grey and fade away after being released so you kind of see where the current chord came from. This isn’t strictly a perk of pre-recordings. While you can feed it MIDI files, you can also play a MIDI instrument and display the visuals live on the hardware version that uses a Teensy with an audio shield.

If you’re looking for examples on how music visualizers are used to teach the instrument, look no further than this Wurlitzer note visualizer replica. Also for those who don’t know, the song being played in the hardware demo (second video below) is Beethoven’s 7th Symphony. Well worth a full listen, it’ll change your life.

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