digital audio hacks

716 Articles

Laser Sound Visualizations Are Not Hard To Make

November 13, 2024 by 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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Pulley System Makes Headphone Cables More Managable

October 3, 2024 by 13 Comments

It’s 2024. You’ve probably got one or more pairs of wireless headphones around the house. [Barnso] prefers wired headphones with a long cable, but he also decries the fact that it often gets tangled in his chair. The solution? A pulley system to make everything easier.

The concept is simple. [Barnso]’s system uses three pulleys. The headphone cable goes to the PC, and then runs over the first pulley. It then runs under a second pulley which is free to move, but weighted so that it naturally wants to fall down under gravity. The cable then comes back up over a third pulley, and then runs to the headphones on [Barnso]’s head. Basically, it’s a super simple cable retraction mechanism that keeps the long headphone cable organized and in one place.

It’s nice to see a simple mechanism that makes life easier, particularly one that solves a problem so many of us have faced in real life. The construction shown in the video is almost (intentionally?) maddeningly hacky but it does the job. If you prefer to go wireless, though, we can show you how to do that too.

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Two hands hold a rounded rectangular case with a small lollipop-shaped cutout. The case is dark grey with a bit of white protruding between the two halves in the middle.

Add USB-C To Your AirPods The Easy Way

October 3, 2024 by 8 Comments

While the death of Apple’s Lightning Connector can’t come soon enough, swapping the ports on their products as “category-defining innovations” seems a bit of a stretch. [Ken Pillonel] has designed a set of streamlined, repairable, USB-C adapters for the AirPods, AirPods Pro, and AirPods Max that show Apple what innovation really means.

If you’ve followed [Pillonel]’s work in the past, you’ll know he’s as a big a fan of repairability as we are here, so this isn’t just a cheap knockoff dongle that’ll be in the trash as fast as your counterfeit wireless earbuds. In the video below, he walks us through his quest start-to-finish to design something compact that gives you all the joys of USB-C without the pain of buying a whole new set of headphones.

We like the iteration on the connector, showing that flexible circuits can do some amazing things, but are still subject to failure at extreme angles. Using a combination of 3D printing, a cool robot sandblasting machine, a pick-and-place, and some old fashioned hand soldering, [Pillonel] treats us to a polished final product that’s put together with actual screws and not adhesive. His designs are all open source, so you can DIY, or he sells finished copies in his shop if you want to give one to your less-than-techy relatives.

[Pillonel] may seem familiar as he’s the guy who added USB-C to the iPhone before Apple and redesigned the AirPods Pro case for repairability. Apple is getting better about repair in some of its devices, for sure, but unsurprisingly, hackers do it better.

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Winamp Releases Source Code, But Is It Really Open?

September 24, 2024 by 57 Comments

The 1990s seem to have reached that point at which they are once more considered cool, and ephemera of the decade has become sought-after. One of the unlikely software hits from the period was Winamp, the MP3 player of choice in an era when time spent on dodgy file sharing sites or peer to peer sharing would snag you almost any music you wanted. Decades later its interface is still widely copied, but now you can try the original again as its source code has been made available. It’s not what we’d call open source though, even though they seem to be making an effort to imply as much with phrases such as “opening up its source code“.

If you’d like to have a go with it you can snag a copy from this GitHub repository, and you’ll need a particular version of Visual Studio 2019 to build it. Any celebrations will be muted though by paragraph five of the Winamp Collaborative License, which prohibits distribution of modified versions or forks, and stipulates that only the official maintainers can distribute it. This doesn’t sound like open source to us, indeed it seems they’re just looking for community maintenance for free, which probably isn’t too surprising from a brand which went all-out to join the NFT bandwagon a couple of years ago.

So have a look for nostalgia’s sake if you want, but we’d suggest going for something more community driven if you want to do anything with it.

Header: Christiaan Colen, CC BY-SA 2.0.

Harmonic Table Keyboard Brings Old Idea Back To Life

June 17, 2024 by 11 Comments

If you missed the introduction of the Axis-49 and Axis-64 keyboards by C-Thru Music, you’re definitely not alone. At the time it was a new musical instrument that was based on the harmonic table, but it launched during the Great Recession and due to its nontraditional nature and poor timing, the company went out of business. But the harmonic table layout has a number advantages for musicians over other keyboard layouts, so [Ben] has brought his own version of the unique instrument to life in his latest project.

Called the Midihex, the keyboard has a number of improvements over the version from C-Thru Music, most obviously its much larger 98 playable keys and five function keys. The keys themselves are similar to Cherry MX keys but which use Hall-effect sensors. This style of key allows the device to send continuous key position information to the host computer, and since this is a MIDI instrument, this capability allows it to support a MIDI protocol called MIDI Polyphonic Expression (MPE) which allows each note to be more finely controlled by the musician than a standard MIDI instrument. The PCB is powered by a Teensy 4.1 at the core.

For any musicians that haven’t tried out a harmonic table before, an instrument like this might be worth trying out. The layout provides easier chord and scale patterns, and for beginner musicians it can have a much shallower learning curve than other types of instruments. If you can’t find an original Axis-49 or Axis-64 anywhere to try out, though, we actually posted a teardown of one way back in 2009 when the company was still producing instruments.

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A3 Audio: The Open Source 3D Audio Control System

June 7, 2024 by 8 Comments

Sometimes, startups fail due to technical problems or a lack of interest from potential investors and fail to gain development traction. This latter case appears to be the issue befalling A3 Audio. So, the developers have done the next best thing, made the project open source, and are actively looking for more people to pitch in. So what is it? The project is centered around the idea of spatial audio or 3D audio. The system allows ‘audio motion’ to be captured, mixed and replayed, all the while synchronized to the music. At least that’s as much as we can figure out from the documentation!

The system is made up of three main pieces of hardware. The first part is the core (or server), which is essentially a Linux PC running an OSC (Open Sound Control) server. The second part is a ‘motion sampler’, which inputs motion into the server. Lastly, there is a Mixer, which communicates using the OSC protocol (over Ethernet) to allow pre-mixing of spatial samples and deployment of samples onto the audio outputs. In addition to its core duties, the ‘core’ also manages effects and speaker handling.

The motion module is based around a Raspberry Pi 4 and a Teensy microcontroller, with a 7-inch touchscreen display for user input and oodles of NeoPixels for blinky feedback on the button matrix. The mixer module seems simpler, using just a Teensy for interfacing the UI components.

We don’t see many 3D audio projects, but this neat implementation of a beam-forming microphone phased array sure looks interesting.

Internals of the Blu-ray player, showing both the blu-ray drive and the custom PCBs

An Ingenious Blu-Ray Mini-Disk Player

June 1, 2024 by 13 Comments

[befi] brings us a project as impressive as it is reminiscent of older times, a Blu-Ray mini disk player. Easily fitting inside a pocket like a 8 cm CD player would, this is a labour of love and, thanks to [befi]’s skills both in electronics and in using a dremel tool.

A BluRay drive was taken apart, for a start, and a lot of case parts were cut off; somehow, [befi] made it fit within an exceptionally tiny footprint, getting new structural parts printed instead, to a new size. The space savings let him put a fully custom F1C100S-powered board with a number of unique features, from a USB-SATA chip to talk to the BluRay drive, to USB pathway control for making sure the player can do USB gadget mode when desired.

There’s an OLED screen on the side, buttons for controlling the playback, power and battery management – this player is built to a high standard, ready for day-to-day use as your companion, in the world where leaving your smartphone as uninvolved in your life as possible is a surprisingly wise decision. As a fun aside, did you know that while 8 cm CDs and DVDs existed, 8 cm BluRay drives never made it to market? If you’re wondering how is it that [befi] has disks to play in this device, yes, he’s used a dremel here too.

Everything is open-sourced – 3D print files, the F1C100S board, and the Buildroot distribution complete with all the custom software used. If you want to build such a player, and we wouldn’t be surprised if you were, there’s more than enough resources for you to go off. And, if you’re thinking of building something else in a similar way, the Buildroot image will be hugely helpful.

Want some entertainment instead? Watch the video embedded below, the build journey is full of things you never knew you wanted to learn. This player is definitely a shining star on the dark path that is Blu-Ray, given that our most popular articles on Blu-Ray are about its problems.

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