MIDI And Vintage FM Synthesis

July 8, 2014 by Brian Benchoff 11 Comments

Before the days when computers could play and record audio that far surpassed the quality of CDs, sound cards were very, very cool. Most audio chips from the 80s, from the Commodore SID is pretty much a synth on a chip, but you can also find similar setups in ancient ISA sound cards. [Emilio] pulled one of these cards with an ADLIB OPL2 chip on it, and used a PIC micro to create his very own FM synthesis synth (IT, translatatron, although Google is screwing up the formatting).

The Yamaha YM3812 chip, otherwise known as the OPL2, was a fairly complete synthesizer in a very tiny package using FM synthesis for some very unique sounds. Once [Emilio] had the PIC sending commands to the sound chip, he added MIDI support, allowing him to play this vintage ‘synth on a chip’ with a keyboard instead of a tracker.

Judging from the video below, it sounds great, and that’s with [Emilio] mashing the keys for a simple demo.

Continue reading “MIDI And Vintage FM Synthesis” →

Keep Those Filaments Lit, Design Your Own Vacuum Tube Audio Equipment

June 4, 2014 by Gregory L. Charvat 120 Comments

It was a cold January Saturday night in Chicago and we had big plans. Buddy Guy’s Legends bar was packed. We setup directly under one of the PA speakers less than 15′ from the stage. Time to celebrate. Skip the glass, one pitcher each and keep them coming. We’re about to make bootleg recording history. Conversation evolved into bloviation on what our cover art would look like, certainly it would be a photo of our battery powered tube mic pre-amp recently created in my basement lab. We had four hours to kill before Buddy’s appearance. Our rate of Goose Island and Guinness consumption would put us at three-sheets to the wind by 11. Must focus. It’s time, Buddy was on. Much fumbling about and forgetting how to turn on the Japanese-made 24 bit digital recorder with its nested LCD menus, cryptic buttons, and late 90’s firmware. Make it work. We did, just in time for the bouncers to notice the boom mike and battery packs. Wait, wait… maybe we should talk about why tube amps are worth this kind of trouble first.

Yes, vacuum tubes do sound better than transistors (before you hate in the comments check out this scholarly article on the topic). The difficulty is cost; tube gear is very expensive because it uses lots of copper, iron, often point-to-point wired by hand, and requires a heavy metal chassis to support all of these parts. But with this high cost comes good economic justification for building your own gear.

This is one of the last frontiers of do-it-yourself that is actually worth doing.

Continue reading “Keep Those Filaments Lit, Design Your Own Vacuum Tube Audio Equipment” →

DIY Gas Can Speakers Blast Your Tunes

April 18, 2014 by Nick Conn 24 Comments

Gas Can Speaker

Have you ever wanted to build your own speakers, but were a bit overwhelmed with all the information out there on cases and packaging? A recent Instructable by [Txje] goes over how to build a set of simple gas can speakers.

While using gas cans as speaker housings will not result in the best audiophile quality sound or be the cheapest option out there, it sure looks awesome, and is a great way to get started with building your own speakers. After testing out the speakers and electronics, holes in the gas cans are cut and the terminals and speakers are installed. “As an added bonus, the pour spout serves to release pressure in the speaker can. You can get everything you need for ~$69 from Amazon and/or Home Depot.” Not a bad price point for two very cool looking speakers. Once you have built the speakers, now you can experiment with different fill material to see what results in better sound quality.

This is a simple, yet fun looking build. Something like this can make a nice gift for someone who spends a lot of time in their garage. What other crazy objects have you used for speaker enclosures?

Raspberry Pi Remote Audio Link

April 17, 2014 by Eric Evenchick 7 Comments

In broadcast, lots of people are still using dedicated analog lines to connect remote sites. These operate like old telephone systems: you call up the operator and request to be patched through to a specific site. They’re also rather expensive.

For a hospital radio station, [Marc] wanted to replace the old system with something less costly. The result is his Raspberry Pi STL in a Box. Inside the box is a Raspberry Pi, PiFace display, a pair of meters, and some analog hardware for the audio.

On the software side, the system uses LiquidSoap to manage the stream. LiquidSoap uses a language to configure streams, and [Marc] has a write-up on how to configure LiquidSoap for this application. On the hardware side, SSM2142 ICs convert the signal from single-ended to balanced. The meters use the LM3915 bar drivers to control the meters.

The Python script that controls the box is provided, and could be helpful for anyone needing to build their own low-cost audio link.

DIY Bluetooth Boombox Can Take A Beating!

March 30, 2014 by James Hobson 18 Comments

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Looking for a nice portable audio solution that can take a beating outdoors? This RaveBOX (v1.0) might be what you’re looking for!

[Angelo] is a 15 year old high school student from the Philippines who loves making things — in fact, he has a collection over 40 Instructables that he’s written himself to share with the world. He wrote his first when he was only 10 years old.

He was inspired to build this boombox when he stumbled upon a Pelican-like rugged case at the mall, so he bought it and started planning the build around it. He’s using a pair of 2-channel audio amplifiers hooked up to a Bluetooth/FM/USB/SD card player module which has a nice face-plate for external mounting. It drives a 4″ woofer, and 4 full range speakers. To modify the case, he used a Dremel and pocket knife, and we must say, he did a great job! The 12V 2.2aH lithium polymer battery provides a surprising 18 hours of playback. Continue reading “DIY Bluetooth Boombox Can Take A Beating!” →

From Wireless Soundbar To Portable Boombox

March 5, 2014 by James Hobson 5 Comments

toshiba-mini-soundbar-online

[Frank] had wanted a portable Bluetooth boombox for a while, but when he did some price comparisons he found that they are pretty expensive. He decided to take matters into his own hands and modify two products he already had — into what he wanted.

The guts of his Frankenstein-boombox come from a Toshiba 3D Soundbar — a great product, but not as durable or portable as he needed. He then took an old mini guitar amp and started hacking the two together.

The soundbar features 4 speakers and a sub woofer — plus the amp and wireless capabilities of course — so [Frank] opted to just use the case of the guitar amp with the soundbar’s innards. He took some measurements and then built up a wooden support for the speakers inside the amp. He’s also sealed off the tweeters sound cavity from the main SUB to keep the sound nice and clear. Continue reading “From Wireless Soundbar To Portable Boombox” →

SoundCube: A Companion Cube That Can Talk

February 23, 2014 by Marsh 2 Comments

sound_companionCube

The Enrichment Center likely disapproves of the SoundCube: a portal music box in the form of a Portal Companion Cube. [Andreas] finished this project a couple of years ago, but we’re glad he’s finally had time to give a rundown on the details at his blog.

The build is primarily a modified speaker box cube—constructed out of what appears to be MDF—with four Alpine SXE-1725S speakers placed at the center of the middle faces. The faces were routed out to resembled the Companion Cube, while the electronics mount and the speaker grills were 3d printed. Inside is a homemade amplifier built around an Arduino Mega, with a TDA7560 quad bridge amplifier, a TDA7318 audio processor, a Belkin bluetooth receiver, and a 3.5″ touchscreen for volume control and for input selections.

Two 12v 7.2Ah lead-acid batteries keep the cube functional for an entire weekend of partying, but probably add a few pounds to the already hefty MDF construction. Check out [Andreas’s] blog for more pictures and his GitHub for all the necessary code.