The Best-Sounding Walnut You’ll Hear Today

November 2, 2023 by Kristina Panos 16 Comments

Do you ever find yourself eating walnuts and think, this would make a great enclosure for something like a Bluetooth speaker? That seems to be exactly what happened to [Penguin DIY].

In the mesmerizing video after the break, you’ll see [Penguin DIY] do what seems to be impossible. They start with a tiny 5 V power bank module which is still not small enough to fit, so they remove all the components and dead-bug them back together.

This is really just the beginning. There of course has to be a female USB of some type, so [Penguin DIY] Dremels out the perfect little slot for it.

They did manage to stack and fit a MH-MH18 Bluetooth audio module and an HXJ8002 mini audio amplifier module in the walnut, but of course, it took a lot of fiddly wiring to extend the LEDs and wire them up.

Then in the other half of the shell went the 4Ω 2 W mini speaker. [Penguin DIY] of course drilled a ton of little holes in the shell for the sound to come through. Also on this side are three tiny switches for play/pause and previous and next track, and the latter two can be long pressed to control the volume. Definitely check this out after the break.

Do the notifications of your Bluetooth speaker annoy you? There’s a hack for that.

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Exploring Hidden Lyrics On 1990s DCC Audio Tapes

September 11, 2023 by Chris Lott 18 Comments

Having a fondness for old and obscure audio and video media formats, [Techmoan] recently revisited the Philips Digital Compact Cassette (DCC) format introduced in 1992. Despite being billed as the successor to Philips’ original analog Compact Cassette format from 1963, DCC was short-lived and slipped away after only four years in 1996. [Techmoan] obtained a unique cassette that purports to be the only known published DCC tape which contains embedded song lyrics that scroll on the DCC player’s tiny screen in sync with the music — “Size Isn’t Everything” by the Bee Gees from 1993. Sure enough, he is able to demonstrate this in the video down below the break.

But, there’s more. For reasons unclear, this only happens on on this one Bee Gees’ album. But it turns out that many DCC tapes did in fact include lots of other metadata, and sometimes lyrics as well. But these were only visible using an unreleased Philips system called Interactive Text Transmission System (ITTS). It just so happens that the folks at the DCC Museum obtained a Philips prototype ITTS box and have been gradually hacking the protocol.

[Techmoan] demonstrates a modernized prototype version from Germany designed by [Thomas Falkner] called the ITTS video box NG. Using this, he runs through a bunch of DCC tapes from his collection, and finds a significant number of them were published with lyrics and metadata, presumably in anticipation of as ITTS launch. It’s interesting to see how some publishers spent a lot of effort to format this information and others seemed to just copy / paste over the bare minimum.

The more elaborate pages resemble what you might see on your teletext screens back in the day. On those albums that do have lyrics, the presentation can be different, as well. Lyrics from the Bee Gees album appear like text scrolling up on a terminal, with current phrases shown in yellow. Another album’s lyrics can be scrolled in different peculiar ways, including a one-word-at-a-time mode.

If this kind of historical dive into technology interests you, check out the talk that [Jac] and [Ralf] gave at the 2022 Supercon about DCC, and this video from 2018 where [Ralf] digs deeper into this topic. Also, [Jac] has some more recent details on hacking the protocol posted over on his Hackaday.io project page. If you want a more basic introduction to DCC, [Techmoan] introduced this format some years ago on his YouTube channel.

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An exploded view of an AirPods Pro case. The outer case consists of two long, capsule-shaped sections that enclose several smaller parts including the wireless charging cable, contacts for charging the AirPods themselves, and the top rounded protective piece for the buds that nestles into the top capsule. This version includes screws to fasten everything together instead of adhesives.

Fixing Some More Of Apple’s Design Mistakes

August 2, 2023 by Navarre Bartz 26 Comments

Love them or hate them, there’s no denying that Apple has strayed from the Woz’s original open platform ideal for the Apple II. [Ken Pillonel] is back for another round of fixing Apple’s repairability mistakes with a full complement of 3D printable replacement parts for the AirPods Pro case.

While modeling all of the parts would be handy enough for repairing a device with a 0/10 iFixit score, [Pillonel] modified the parts to go together with screws instead of adhesive so any future repairs don’t require cracking the plastic egg. He says, “By showcasing the potential for repairability, I hope to inspire both consumers and multi-billion dollar companies, like Apple, to embrace sustainable practices in their products.”

[Pillonel]’s repairability exploits may seem familiar to readers from his previous work on adding USB-C to the iPhone and the AirPods Pro case. If you just need to retrieve a lost AirPod, you might try an electromagnet, or you can make a Bluetooth receiver from a pair of knock-off buds.

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Planar Speaker Build Uses Hard Drive Magnets

July 15, 2023 by Al Williams 3 Comments

We like to see people building things that are a little unusual, and we really like it when said unusual thing uses salvaged parts. This project from [JGJMatt] ticks all our boxes — the build creates a planar speaker that uses salvaged magnets from a hard drive.

A planar speaker, according to the post, uses wires and magnets to manipulate a flat film that acts as the transducer. The speaker housing is 3D printed and looks great but is otherwise unremarkable. The fun starts when a Dremel with a diamond disk cuts the magnets in half. Cutting neodymium poses several challenges. For example, if you heat the material up too much while cutting, it can lose its magnetism.

With the proper magnets, you can move to the tedious method of creating the coils. The post shows three different methods. But the part we really liked was using a resin 3D printer as a UV source to expose a resist mask which transfers to a copper or aluminum foil that will be the sound-generating film. [JGJMatt] used a similar technique to put resist on PC board blanks, too. Unfortunately, there were some issues so the finished speakers didn’t use the foil prepared using this method. Instead, a quick modification to the resin printer allowed a thin film of resin to rest on the foil, which was then exposed.

Once you have the pieces, there isn’t much left to do but put them together. Honestly, this is one of those things you probably won’t do yourself unless you are obsessed with speakers. But there were a lot of interesting techniques here that might come in handy, even if you don’t care about audio reproduction.

[JGJMatt] showed us a ribbon speaker before. We have seen some speakers that are practically all 3D printed.

A small black microphone in a black 3d printed mount. The mount is attached to an adjustable silver neck attached to a desk clamp from an IKEA lamp.

IKEA Hack – Kvart Into Mic Stand

June 23, 2023 by Navarre Bartz 21 Comments

While audiophiles might spend gazillions of hours finely honing a microphone stand that isolates their equipment from the trials and perturbations of the world, most of us who use a microphone don’t need anything so elaborate. Hackaday contributing editor [Jenny List] hacked together some thrift store finds into a snazzy adjustable mic setup as you can see in the video below the break.

Using the flexible neck and clamp of an IKEA Kvart as a base, [Lists]’s mic stand looks like a simple, but exceedingly useful tool. She first removed the lamp, shade, and cord before designing a 3D-printed mount to attach to the lamp’s neck. Since the bolted lamp end of the connection goes straight to an action camera mounting system, we can see this being handy for mounting any number of other things besides microphones. Another 3D-printed mount attaches the Logitech gaming microphone to the action camera connector, and the whole thing can either be bolted together or use a printed pin. All the parts can be found in a GitHub repository.

Looking for more microphone hacks? Check out this DIY ribbon microphone or the Ambi-Alice ambisonic mic.

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Know Audio: Distortion Part One

June 6, 2023 by Jenny List 28 Comments

If you follow audiophile reviewers, you’ll know that their stock-in trade is a very fancy way of saying absolutely nothing of quantifiable substance about the subject while sounding knowledgeable about imagined differences between devices that are all of superlative quality anyway. If you follow us, we’ll tell you that the only reviews that matter are real-world measurements of audio performance, and blind listening tests. We don’t have to tell you how to listen to music, but perhaps it’s time in our Know Audio series to look at how audio performance is measured.

Before reaching for the bench, it’s first necessary to ask just what we are measuring. What are the properties which matter in an audio chain, or in other words, just what is it that makes an audio device good?

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Op-Amp Challenge: Compare Op-Amps, By Listening To Them

May 7, 2023 by Jenny List 31 Comments

In the world of audiophilia there are arguments that rage over the relative merits of particular components. Sometimes this can reach silly levels as in the high-end ALPS pot we once saw chosen as a volume control whose only task was to be a DC voltage divider feeding a pin on a DSP, but there are moments where such comparisons might have a bit of merit. To allow the comparison of different op-amps in a headphone amplifier, [Stephan Martin] has created a stereo amplifier board complete with sockets to take single or dual op-amp chips.

The circuit is based upon a design from the 1990s which as far as we can see is a pretty conventional non-inverting amplifier. It has an on-board op-amp to create a virtual ground, and three sockets for either two single or one dual op-amp to create a stereo headphone amplifier.

So the burning question is this: will you notice a difference? We’re guessing that assuming the op-amps under test are to a sufficient specification with a high enough impedance input and enough output current capability, the differences might be somewhat imperceptible without an audio analyser or the hearing of a ten-year-old child.

Need more of an audio fix? Try our Know Audio series.