MIDI-Controlled Intellivoice Synth

intellivoice

Mattel Electronics presents…

Intellivoice
Boom!

It’s been a long time since I started this project, but I’ve finally got my Intellivoice Synth running.

Since last time, I added MIDI control and transferred things to a smaller circuit board (and Arduino) in order to fit everything back in the original case.

intellivoice
Working out how to get the new guts into the old housing
intellivoice
USB MIDI control, 1/4″ output

So what does this little synth do? It takes MIDI notes (from a keyboard or DAW), and uses them to trigger the sounds built in to the Intellivoice chip, which, as it turns out, consist of mostly numbers.

Check it out:

I might look into a few more tweaks. Currently, each word will always play to the end, even if another word is performed before it’s finished. I’m not sure if this is a property of the Intellivoice chip, or something I could fix in my Arduino program.

Why pursue a project like this one?

Games and gaming hardware are mass-produced devices with planned obsolescence and few serviceable parts. By “hacking” and customizing gaming hardware we regain personal ownership of these devices, and we can turn obsolete equipment into performable, expressive instruments.

intellivoice
A few last-minute modifications to the audio-chain

An earlier version of this synth actually appears in the electronics of my new commissioned work, Hirazumi (more about the piece here and here), and I think the hacked Intellivoice fits perfectly into the post-digital, cyberpunk aesthetic.

MIDI-Controlled Sega Genesis Video-Glitch – Part 3

Back to the Sega Genesis Mods! If you’re catching up, check out Part 1 and Part 2.

Where we left off, I had found my glitch points, and I was going to get digging in to some kind of button control before moving on to MIDI control.

Wires soldered to the underside of the VRAM
Wires soldered to the underside of the VRAM

Here are the pins of the VRAM with some wires from some selected spots. Purists might fault me for not running off of all of the 44 available points (48 minus the two VCCs and two grounds), but I didn’t have that many buttons anyway.

Not a huge fan of electrical tape, but what can you do?
Not a huge fan of electrical tape, but what can you do?
Wires run to a set of female headers
Wires run to a set of female headers

After taping things down, I ran the wires to a set of headers. The reason for using headers is to keep the ability to remove the top of the Genesis if I want to get back inside for any reason.

Female headers plug into phone keypad
Female headers plug into phone keypad

I had a phone keyboard kicking around, and I figured this would be a simple alternative to setting up a matrix of buttons. How this works, then, is any one button connects two points (which two points hardly matters), and if one holds down multiple buttons at the same time, several data points start cross-talking with different visual results

Are you ready for this?

Behold!
Behold!
The Keypad-Controlled Glitch Genesis!
The Keypad-Controlled Glitch Genesis!

Here’s a video of it in action:

Now, of course, while I’m stoked about my new toy, this instrument is not yet what I set out to do (and what the title of these posts proclaims).

MIDI-Control, though is just a quick hop away. Next time, I’m going to get a new Teensy, install it in the Genesis, and program it to control the connections via USB MIDI control (likely with some simple transistor work).

Almost there!

MIDI-Controlled Sega Genesis Video-Glitch – Part 2

Continuing my Sega Genesis Project, now that I’ve got the video in a form my TV can understand, time to start messing with things.

Repeating my disclaimer: Messing with things plugged into an outlet is dangerous! I’m only doing this because the Genesis has an adapter that converts the voltage to 10V DC long before the power gets anywhere near the board.

When in doubt, only circuit-bend things that are battery powered. Think of how embarrassing it would be for your parents (or wife and son) to explain that you died trying to get glitchy video from a game system.

Anyway, that said, time to start poking around a bit.

I guess this is all you really need
I guess this is all you really need
The VRAM
The VRAM

These are the Video RAM chips whose connections I’m going to bridge. They have 24 connectors apiece, and one on each is the power, one on each is the ground, everything else (I believe) is data. So all we’re going to do is send some of that data to the wrong places.

The VRAM from the bottom
The VRAM from the bottom

I’m going to poke around the bottom here, because the contacts are more accessible.

(By the way, the resistor and capacitor you see here are not my work, just an afterthought by the designers of the PCB.)

Let the fun begin!
Let the fun begin!

That looks pretty glitchy to me.

I’ve found a few points that give a variety of effects (relatively). The next step (next time) is going to be installing a way to control these. I’ve decided I’m going to start with a push-button system before moving on to the MIDI control for two reasons:

1.) Moving in small steps seems wise.
2.) I’ve used up this month’s tinkering budget, and I’m going to need a Teensy to get the MIDI working.

Until next time!

MIDI-Controlled Sega Genesis Video-Glitch – Part 1

A few weeks ago, I picked up an old Sega Genesis with the hopes of doing a little bit of tinkering (emboldened by my Game Boy customization projects).

The Genesis uses a Yamaha FM synthesis chip for sound, which might be interesting to dig into at some point, but my main goal in cracking this machine open was to try some video circuit-bending: apparently pretty easy to do, bridging the legs of the VRAM.

First, though, I didn’t have the little box that I need to hook the Genesis up to the TV, so, instead of trying to track one down, I decided to install component video RCA outs.

So, away we go!

The Sega Genesis Board
The Sega Genesis Board
A
A “VA7,” alas

After some poking around on the internet, I found that there are lots of different revisions to the Genesis circuit board, and this, the VA7, is apparently the least desirable. The audio is actually synthesized on a different chip, but Sega didn’t account for the difference in output volume of the new chip in the internal amplifier, so the sound has all kinds of digital distortion.

Well, that just means if I fry this thing, I won’t feel so bad.

Wires for component out
Wires for component out
Testing the component out
Testing the component out

Quick disclaimer: Messing with things plugged into an outlet is dangerous! I’m only doing this because the Genesis has an adapter that converts the voltage to 10V DC long before the power gets anywhere near the board.

When in doubt, only circuit-bend things that are battery powered. Think of how embarrassing it would be for your parents to explain that you died trying to get glitchy video from a game system.

Some quick audio mods
Some quick audio mods

Hearing the complaints about the sound on the VA7, I did a quick adjustment by adding a resistor to pull things down a bit, and a capacitor to roll off some highs (I think that’s how it works. Someone please correct me if I’m wrong).

I’ve since found someone designed a Crystal Clear Audio Mod, which seems a lot more involved (and likely better) than my “quick and dirty” solution.

Looks like it all works!
Looks like it all works!

Success! Next step: start glitching that video feed.

Check back for Part 2 soon.

“Inspiration does exist, but it must find you working.” – Pablo Picasso

Custom “Pro Sound” Game Boys

my first two custom Game Boys, BUDO (left) and MIKAN (right)
My first two custom Game Boys, BUDO (left) and MIKAN (right)

Since the winter break, I’ve been tinkering around with some chiptune projects, and I’ve got quite caught up in the simultaneous progressive and regressive sound design of composing with chips of the 1980s and 90s. Perhaps its a stretch, but I believe this kind of cultural re-appropriation as directly akin to drawing influences from outside Western Music.

Philosophy aside for the moment, as my first gaming system was the original Game Boy, I’m particularly interested in the circuit-bending and customization artists are doing with these old devices, so I’ve been getting my hands dirty for the last couple of months customizing these two Game Boys that I picked up on Craigslist.

While a lot of the work was purely cosmetic, I did a “Pro Sound” mod on both of them, which basically is just bypassing the internal (noisy) headphone amplifier and putting in some RCA jacks. On the Game Boy Color here, I also bypassed the existing audio output capacitors with some bigger ones, which supposedly gives a bass boost. While I hope to do some more experimenting in the future, most of what I did to these two units was a matter of just following instructions.

I’m calling the original Game Boy “MIKAN.” Customizations:

  • Orange screen backlight
  • “Pro Sound” RCA Mod
  • Custom buttons, ON/OFF switch, screen lens, link cover, orange LED, and battery cover

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2015-04-02 17.12.45

2015-04-02 17.13.23

The Game Boy Color, “BUDO,” has:

  • Green LED
  • Original (broken) speaker replaced with Nintendo DS speaker
  • “Pro Sound” with bass boost capacitors to RCA outs
  • “Anti-noise” decoupling capacitor

2015-03-07 17.50.28 HDR

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2015-04-02 17.14.41 HDR

They both have their own peculiarities in terms of sound. BUDO has some sub-audio in its output (perhaps a result of the bass boost), and MIKAN, without a decoupling capacitor, sometimes has “clicks” at the start of sounds (perhaps related to the DC power somehow). I’ll post some sound samples as I keep working on my current project.

I have to say it’s really fun and rewarding to do these customizations. While I’m working on a piece now that uses these “instruments,” I’m also trolling Craigslist for another cheap Game Boy so I can do the customizations again (and try some new things).

Of course, lest I give the impression that I’m the first one to be playing with the ideas in the realm of concert art music, check out this fantastic piece by Matthew Joseph Payne, performed by Meerenai Shim, flight of the bleeper bird.

SN76489 Chip-Based Synthesizer

Over the break, I took some time to put together an arduino-driven synth from this “instructable” by Brian Peters.

2015-02-03 17.36.47
Yeah, inside the radio case

This is a synthesizer made from four SN76489 chips. These chips appeared as a cheap audio solution in a number of old computers and game consoles, including the ColecoVision, NeoGeo Pocket, Sega Genesis (although the Genesis had another chip capable of FM Synthesis).

Because these chips are cheap, this ends up being the cheapest synth on my rack:

$19.00 – Teensy 2.0 Board
$4.50 – 4x SN76489AN Chips (includes shipping)
$1.30 – 1.8432 MHz Oscillator
$0.10 – 4x 75k Resistors
$0.10 (or so) – 4x 10µF Capacitors
$5.00 – 4x 1/4″ Audio Jacks (these were way too expensive on Sparkfun)
$5.00 – Breadboard

$45.00 – Total (give or take)

So, it’s been about 15 years since I bought it, but I think that’s even cheaper than my Alesis Nanobass (appears in the background of these photos).

Why did I put it inside and old radio? Because that was what I found a Goodwill for $2 that was an appropriate size.

The aptly named Arduino "Teensy"
The aptly named Arduino “Teensy”

Teensy, SN76489 chips, and quartz clock ready for wiring
Teensy, SN76489 chips, and quartz clock ready for wiring

The rats' nest
The rats’ nest

So what does it sound like? Here’s a quick and dirty demo:

RCA Output on a Super Game Boy

Always looking for an excuse to open something up
Always looking for an excuse to open something up

For my latest “chiptune” project, I’ve put in some RCA jacks on my Super Game Boy.

Of course the Super Nintendo already has the possibility of a component out (via RCA jacks), but, since the Super Game Boy basically contains all the circuitry of the Game Boy, this mod bypasses the Super Nintendo altogether.

If you’re interested in trying this yourself, check out this instructable for step-by-step instructions.

Super Game Boy guts
Super Game Boy guts

Testing...
Testing…

Closed back up
Closed back up

So… Does it sound better? I don’t really know, and I don’t really have the time to set up a comparison, but this mod sure makes it easier to get sound to my mixer.

Here are a couple quick recordings of games I had lying around:

Battletoads

[audio:http://www.simonhutchinson.com/BattleToads.mp3]

Ninja Gaiden

[audio:http://www.simonhutchinson.com/NinjaGaiden.mp3]

The thing I have to be careful of, though, is that the clock speed of the Super Game Boy (4.295 MHz) is 2.4% faster than the Game Boy (4.194 MHz). A minor change, certainly, but a significant one if I’m trying to keep my music in tune between different devices, and I’m switching between the SNES and a Game Boy.

…like the time I brought my NOPera to Germany, forgetting that Europeans don’t tune to A440.