Know Audio: A Loudspeaker Primer

June 25, 2021 by Jenny List 27 Comments

As we’ve started out on our journey through the world of Hi-Fi audio from a strictly practical and engineering viewpoint without being misled by any audiophile woo, we’ve already taken a look at the most important component in any audio system: the listener’s ear. It’s time to move down the chain to the next link; the loudspeaker.

Sound is pressure waves in the air, and the purpose of a loudspeaker is to move the air to create those waves. There are a variety of “exotic” loudspeaker technologies including piezoelectric and electrostatic designs, here we’ll be considering the garden variety moving-coil speaker. It’s most usually used for the large bass or smaller mid-range drivers in a typical speaker system. Continue reading “Know Audio: A Loudspeaker Primer” →

Modifying A SNES Rom To Be Widescreen

June 22, 2021 by Matthew Carlson 7 Comments

Turning a game like Super Mario World for SNES into a widescreen game is not a small task, but [Vitor Vilela] accomplished just that. [Vitor] has a long list of incredible patches such as optimizing code for better frame rates and adding code to take advantage of the SA-1 accelerator chip, so out of anyone he has the know-how to pull a widescreen mod off. This patch represents a true labor of love as many levels were designed with a specific screen width in mind. [Vitor] went through each of these single-screen width levels and expanded them by writing the extra assembly needed.

On a technical level, this hack was achieved by using the panning feature built into the game. The left and right shoulder buttons allowed a player to pan the camera to the left and right. The viewport is considered to be two times the screen resolution and so items will be rendered within the widescreen resolution. By taking away the panning feature and render a larger section of the viewport to the screen, you get a widescreen view. However, to save cycles, enemies and items don’t start moving until they get close to the screen edge. So how do you make a game widescreen without ruining the timing of every enemy that spawns? Suddenly the hours of muscle memory that fans have drilled in over the years is a disadvantage rather than a strength. The answer is a significant time investment and an eye for detail.

All the code is available on GitHub. A video of a playthrough of the mod is after the break.

Continue reading “Modifying A SNES Rom To Be Widescreen” →

IPod HiFi Gains New High Notes

June 19, 2021 by Jenny List 1 Comment

The iPod HiFi was a stereo speaker add-on produced by Apple in the mid-2000s for their iPod range, a $300-plus speaker cabinet with twin drivers per channel, an iPod dock, aux, and TOSLINK interfaces. It’s caught the eye of [Jake], in particular one posted on Reddit that had an extra set of tweeters to improve the HiFi’s lackluster treble. The question was that it might have been an Apple prototype, but lacking his own [Jake] set out to replicate it.

The job he’s done is to a high quality. The baffle has first 3D scanned, and then recesses were milled out of it so the tweeters could be press-fit in. He’s driving them through a simple LC crossover circuit taken from the speaker drive, and reports himself happy with the result.

Unfortunately, we still don’t know whether or not the Reddit original was an Apple prototype or not. We’d be inclined to say it isn’t and praise the skills of the modder who put the tweeters in, but in case it might be we’d point to something that could deliver some clues. The iPod HiFi didn’t use a passive crossover, instead it had a DSP and active crossover, driving four class D amplifiers. If you find one with tweeters and they’re driven from the DSP through an extra pair of amplifiers then put it on eBay as a “RARE BARN FIND APPLE PROTOTYPE!” and make a fortune, otherwise simply sit back and enjoy the extra treble a previous owner gave it.

Of course, some people baulked at the price tag of the Apple speaker, and made their own.

Is It A Plasma Tweeter Or A Singing Tesla Coil?

June 19, 2021 by Jenny List 6 Comments

When our ears resolve spatial information, we do so at the higher treble frequencies rather than the bass. Thus when setting up your home cinema you can put the subwoofer almost anywhere, but the main speakers have to project a good image. The theoretical perfect tweeter for spatial audio is a zero mass point source, something that a traditional speaker doesn’t quite achieve, but to which audio engineers have come much closer with the plasma tweeter. This produces sound by modulating a small ball of plasma produced through high-voltage discharge, and it’s this effect that [mircemk] has recreated with his HF plasma tweeter.

A look at the circuit diagram and construction will probably elicit the response from most of you that it looks a lot like a Tesla coil, and in fact that’s exactly what it is without the usual large capacitor “hat” on top. This arrangement has been used for commercial plasma tweeters using both tubes and semiconductors, and differs somewhat from the singing Tesla coils you may have seen giving live performances in that it’s designed to maintain a consistent small volume of discharge rather than a spectacular lightning show to thrill an audience.

You can see it in operation in the video below the break, and it’s obvious that this is more of a benchtop demonstration than a final product with RF shielding, It’s not the most efficient of devices either, but given that audiophiles will stop at nothing in their pursuit of listening quality, we’d guess that’s a small price to pay. Efficiency can be improved with a flyback design, but for the ultimate in showing off how about a ring magnet to create the illusion of a plasma sheet?

Continue reading “Is It A Plasma Tweeter Or A Singing Tesla Coil?” →

Enterprise Helm Commands The Entertainment Center

June 5, 2021 by Tom Nardi 11 Comments

Many a young geek wished they could get a chance to sit at the helm of the USS Enterprise, wildly tapping on unlabeled technicolor buttons with the self-assured confidence of a proper Starfleet officer. For most of us it was a dream unrealized, but right now somebody in the Seattle, Washington area is getting to do exactly that in their media room. We won’t deny being jealous, but at least our collective egos can take some comfort in the knowledge that they had to outsource the construction of their replica helm to the fine folks at [Blackmouth Design].

There’s not a lot of technical details to be had, but considering the page for this project is only meant to show off the company’s design and fabrication skills, we can’t blame them too much. If we were in the business of selling these things, we’d probably keep some of the juicer details under wraps too.

But we do know there’s “Arduino technology” under the hood that fires up different light and sound effects depending on which of the vintage rocker switches has been flipped. The red momentary buttons lined up on the right side of the coffee table sized panel are tied into the home media center to do things like turn off the lights and lower the projector screen. Check out the video below for a brief demo.

In a post on Reddit, one of the engineers behind the project explains that the top surface of the helm is 3/16″ powder coated aluminum, with the plywood that makes up the base laminated in the classic Original Series color scheme of red, grey, and black. The artwork for the astrogator was created from scratch, backlit with LEDs, and placed behind a 1/4″ acrylic panel for protection. We imagine the fact that it’s parallel to the ground means it’s supposed to be a space to place your drinks or popcorn, though if it was in our house, nobody would be bringing food or drink anywhere near it.

In all honesty, while Hackaday is decidedly more about building than buying, we can’t fault anyone for forking over their hard earned cash for craftsmanship of this caliber. After all, we’ve had our eyes on that officially licensed tricorder replica for quite some time now.

Continue reading “Enterprise Helm Commands The Entertainment Center” →

Know Audio: Start At The Very Beginning

June 2, 2021 by Jenny List 21 Comments

A lot of our projects make noise. It can be something as simple as a microcontroller driving a small speaker or a truly ambitious Hi-Fi project, but common to all of them is the desire to get that sound out in as audible and high-quality a manner as possible. We’ve been known to make fun of the more preposterous side of the Hi-Fi world at times, but behind it all there’s a basis of solid and provable audio engineering that can be brought to bear on almost any project involving sound and electronics. Perhaps it’s time to devote some time to a series exploring the topic, and what better place to start than the ultimate destination for all that sound. Any Hi-Fi is only as good as the ears of the person listening to it, so in out journey through the world of audio that’s where we’ll start. Continue reading “Know Audio: Start At The Very Beginning” →

A Wireless Speaker Pair From Dead Earbuds

May 5, 2021 by Danie Conradie 23 Comments

Building a Bluetooth speaker is easy with the availability of cheap Bluetooth receivers, but surprisingly there isn’t a simple way to build a pair of truly wireless stereo speakers. [Matt] from DIY Perks realized that modern Bluetooth earbuds contain all the electronics to do just that.

Due to the popularity of these earbuds, a broken pair can be picked up very cheaply on eBay. Usually, it’s only the battery or speaker unit that give out, neither of which are required for this build. [Matt] goes through the process of taking a pair of earbuds apart, and then soldering on battery and speaker wires. The speaker wires are connected to an audio amp, which drives a mid-range and treble speaker driver, and a subwoofer. The outputs to the amp are also filtered to match the speakers. Power is provided by a set of four 18650 cells.

[Matt] housed the driver and electronics in some attractive CNC machined wood enclosures. In the video, he places a lot of emphasis on properly sealing all the gaps to get the best possible audio quality. As with all of his projects, the end result looks and performs like a high-end commercial product. We’re almost surprised that he didn’t add any brass to the speakers, as he did on his USB-C monitor or PS5 enclosure build. Continue reading “A Wireless Speaker Pair From Dead Earbuds” →