Cheap Speakers Sound Great In A Proper Enclosure

July 26, 2019 by Lewin Day 31 Comments

It’s possible to pick up a low-cost set of speakers for a few dollars, but by and large, you don’t get a lot of quality for your money. Expect a small pair of drivers, with tinny sound and ugly noises from the enclosure’s cheap materials. [JSK-koubou] has shown us, however, that these speakers can become so much more.

The internal structure helps improve the frequency response.

In this case at least, the basic speaker drivers and electronics inside were passable. Harvesting these, the builder then proceeds to create a stunning pair of tuned wooden enclosures for the speakers. This is achieved with a routing template, large blocks of wood and plenty of elbow grease.

The internal structure makes a huge difference to the bass response of the speakers, allowing them to far more faithfully recreate the music under test. Thanks to the artisan-level craftsmanship, the final product is stunning to look at, too. It’s impressive just how well a cheap pair of drivers can perform with a proper enclosure, and of course, there’s nothing to stop an even better set of drivers being installed, either.

When building your own speakers, your creativity is the limit. Video after the break.

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XFM: A 32-Voice Polyphonic FM Synthesizer On An FPGA

July 24, 2019 by Maya Posch 27 Comments

There’s something about Frequency Modulation (FM) synthesizer chips that appeals to a large audience. That’s one of the reasons behind [René Ceballos]’s XFM project, aiming to duplicate on an FPGA the sound of pure-FM synthesizer chips of the past such as the Yamaha DX series, OPL chip series and TX81Z/802/816. The result is a polyphonic, 32-voice, 6-operator FM synthesizer stereo module.

The project page goes into a lot of detail about the design choices which ultimately led to XFM being implemented on an FPGA, instead of using a dedicated DSP or MCU. Coming from the world of virtual synthesizers running on PCs, [René ]’s first impulse was to implement something on a Raspberry Pi or equivalent. Unfortunately these boards require a lot of power (ruling out battery-powered operation) and can hardly be called real-time, which led [René ] to abandon this attempt.

The design choice against the use of an MCU is simple: though capable of real-time processing, they lack the necessary power to make them a good choice for audio-processing. Working through the calculations to determine what kind of processing power would be needed, it was found that around 650 MIPS would be needed, a figure which most MCUs struggle to achieve a fraction of.

As one of the further requirements for XFM was that it should be as cheap as possible, this ruled out as too expensive the DSP chips which do have the power and hardware features needed. The component chosen was a Xilinx Spartan 6 FPGA, which though somewhat infamous and shunned in FPGA circles turns out to be a very economical option for this project.

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Probability-Based Drummer Leaves The Beats Up To Chance

July 23, 2019 by Erin Pinheiro No comments

Drum machines may seem like one of the many rites of passage for hardware makers, they’re a concept you can implement simply or take into the extreme making it as complex as you want. [Matt’s] DrumKid is one of them, and its long development history is wonderfully documented in the project logs.

[Matt’s] original intention was to use the automatic drummer as part of his band, wanting “the expressiveness of a good drummer but without the robotic tendencies of a simple drum machine”. For that, he created the first iteration of the DrumKid, a web-based project using the Web Audio API. The interface consisted of bars showing levels for different settings which could be intuitively tweaked, changing the probability of a drum sound being played. This gave the “drummer” its unpredictability, setting itself apart from any regular old drum machine.

Fast forward a few years, and [Matt] now wants to recreate his DrumKid as a proper piece of musical gear, porting the concept into a standalone hardware drum machine you can plug into your mixer. He decided to go with the Arduino framework for his project rather than the Teensy platform in order to make it cheaper to build. The controls are simplified down to a few buttons and potentiometers, and the whole thing runs off of three AAA batteries. Also, targeting the project for hardware like this allowed for new features to be added, such as a bit-crush filter.

We already saw the first prototype here on Hackaday when it was featured in a Hackaday Prize mentor session, and it’s nice to see how the project evolved since. After a number of revisions, the new prototype takes design cues from Teenage Engineering’s “Pocket Operator” drum machine, using the main PCB as its own faceplate rather than a 3D printed case in a familiar way we’ve seen before. Unfortunately, the latest board is non-functional due to a routing mistake, but you can see the previous working prototypes in his project logs.

DIY Teensy Looper Multiplies Music

July 23, 2019 by Kristina Panos 10 Comments

If you’re into electronic music, chances are good that you like to roll your own. While step one is usually to build something, anything that makes sound, a natural step two is to build a looping device to extend and play with those sounds.

[Cutlasses] has finished version one of his Teensy-based Eurorack-style looper. He plugs in a thing, records some tunes, and the resulting loop gets divvied up into eight equal pieces. He can cut the loop together live using the eight buttons to jump around between sections. It supports unlimited overdubs, although too many will cause clipping. But hey, that just means free derivative sounds.

The looper records its audio to an SD card. Since this is typically a slow endeavor, [Cutlasses] used two circular buffers. One reads audio, and the other writes it. This took a lot of trial and error, which he may have to repeat with future SD cards.

[Cutlasses]’ plans for future versions include a separate audio CODEC for better sound, CV control, and a pedal option for hands-free operation. We’d love to hear some sweet Theremin loopage, wouldn’t you? Jog past the break to watch [Cutlasses] demo his looper with a kalimba and a DIY noise box that uses a string bow to make metal tines sing.

Feeling out of the music-making loop? There are (slightly) easier ways. Check out this LEGO looper or this multiplayer Pi-ano.

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Forget The Walkman: It’s The Headphones

July 22, 2019 by Jenny List 27 Comments

Forty years ago this month, a product was launched in Japan that would have such a huge impact on the consumer electronics market that we are still using its descendants today. The story goes that one of the Sony founders would listen to music while traveling for the business, and found the company’s existing products cumbersome and awkward so asked his engineers to design something more convenient.

The resulting prototype became the Sony MDL-3L2, a set of miniaturised hi-fi headphones with distinctive foam earpads and a sliding metal headband that in total weighed an astoundingly svelte 45 g. It was paired with a cassette player called a “Walkman” derived from the company’s existing recorder that had been intended for journalists, and went on to sell in the millions. The market for headphones would never be the same again, and if you have a set of lightweight cans in your possession then this was their revolutionary progenitor.

But Hang On, What’s So Special About Headphones?

You probably won’t have heard the Walkman’s 40th anniversary described in those terms in the various reports covering the event, because of course the social impact of the portable music player rather than its headphones is what people remember. The joy of making a mix tape, of listening to The Human League on the bus, and of the adult disapproval of anything involving Kids Having Fun. Previously, music had been a static affair involving bulky record players, but now it could be taken anywhere. The other youth audio icon of that era, the boombox, simply couldn’t match the Walkman, and everybody wanted one.
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Weather Station Can Rock You Like A Hurricane

July 22, 2019 by Sven Gregori 5 Comments

People love to talk about the weather. It’s the perfect small talk, whether you’re trying to start a conversation or keep one going by avoiding an awkward silence. In the same fashion, weather stations are an ideal starting point for any sort of sensor-related project ideas. You get to familiarizing yourself with communication buses, ADCs, general data acquisition, and you learn a lot in figuring out how to visualize it all.

What if your weather station didn’t visualize anything? [OttoNL] is answering that question with a MIDI-generating Weather Station that uses the mood of the music to convey the condition of the elements outside.

Using an ESP8266 programmed via the Arduino IDE, [OttoNL] hooked up a light dependent resistor, a rain sensor, and the all-round workhorse BME280 for temperature, barometric pressure, and humidity to it. Reading the sensors, the ESP will generate MIDI notes that are sent to a connected synthesizer, with each sensor influencing a different aspect of the generated MIDI signals. A sadder, slow tune will play during rain and a fast upbeat one during sunshine. While it doesn’t use the ESP’s WiFi functionality at all at this point, a future version could easily retrieve some weather forecast data from the internet and add it into the mix as well.

Connect this to your alarm clock, and you can start your day off in the appropriate mood. You can even customize your breakfast toast to really immerse your morning routine in abstract weather cues.

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Flashing LEDs With MIDI, Note By Note

July 17, 2019 by Lewin Day 3 Comments

Musical keyboards that light up the correct notes to play have long been touted as a quick and easy way to learn how to play. They’re also fun to look at. [Shootingmaker] has developed a similar concept, with a keyboard lookalike, covered in LEDs (Youtube video, embedded below).

The project consists of a PCB, in which the design of the mask imitates the white and black notes of a piano. This makes it look like a keyboard, but as far as we can tell, it doesn’t actually work as one. All the notes are fitted with APA102 addressable LEDs, under the control of a Teensy 3.2 board, operating in USB-MIDI mode. The Teensy receives MIDI data, and then directs the individual LEDs to flash in different colors based on which MIDI channel fired the note.

It’s a fun way to visualise MIDI data, and we think it would be even more fun combined with a basic synthesis engine to make some noise. We suspect it wouldn’t be too hard to integrate the project into an existing instrument, either. Software is available on Github for those interested in replicating the project. You can use MIDI to control neon lights, too.
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