“Really Dumb” MIDI Monitor For RetroCade


Forum member Offroad recently hit us up with an example project, which is  based on the Papilio Pro and the RetroCade Synth. He’s calling it the Really Dumb MIDI Monitor.  This deserves a bit of explanation:

For starters, Offroad explains what he means by the term, “really dumb meaning: All the fun stuff like printf(“%02c”, byte) happens in RTL state machines…”

The project includes a simple MIDI parser for note on-/off messages. It remembers the state of all keys (all channels are combined, “omni mode”). Maybe this could be useful for some MIDI music experiments with minimal fuss: Excluding UARTs and FIFO (reused modules), the actual RTL code that does all the work is only about two screen lengths.

Here are a couple of links to the actual examples that he created, so make sure to click through and check them out for yourself.

  • Papilio Pro MIDI Monitor – (zip file)
  • meepMeep – (zip file) – This one is a MIDI monitor that actually makes an audible impression with an 18-bit saw waveform.  Offroad says it sounds like a Farfisa!  (See image above) Yikes indeed!

Do any of you guys have anything interesting that you’re working on for the RetroCade?  We’d love to hear about it!  Feel free to post to the forums, or comment on this post!  Right on.

(via the forums, and thanks to Offroad)


Firing Up The RetroCade Synth: First Impressions

We found another great article by Phillip Howard from Raspberry Pi @ Gadgetoid, this time on Getting Started With The Papilio RetroCade Synth. In the image above, you can see the RedroCade MegaWing plugged into its host Papilio Pro. This is the setup that Phillip used for the purposes of his article.

After some initial fussing with Windows 8 drivers and dealing with a reversed polarity situation from MIDI note on/off commands, Philip found himself having a genuinely great time with the synth. Let’s check out some of his findings from the article:

The beauty of the RetroCade is not that is incorporates an FPGA clone of the legendary Commodore 64 SID and Yamaha YN-2169 chip, but that both these hardware implementations, and the Arduino-like Sketch used to drive them are completely open and user-editable.

Playing with the RetroCade was a nice, Friday-friendly introduction to Papilio and once everything was up and running it was really a joy to play. The synthesizer is alarmingly powerful, and exudes nostalgia, but the software has both room for improvement and the opportunity for any user to delve in and make those improvements.

We really appreciate the kind words and your candor, Philip. I know that many people are excited to give the whole synthesizer hacking thing a go, and your article shows that it is really not as difficult as one might imagine it to be.

This is a great segue to a new blog series we will be sharing with you during the coming weeks in this space. We will be sharing a first-timer’s efforts in using the Papilio Pro, the Retrocade Synth, and the LogicStart! Should be interesting!

You can check out Phillip’s full article on his RetroCade experiences here.

(via Raspberry Pi @ Gadgetoid)

Sale! $20 Off Papilio Pro And RetroCade Synth Bundle!

Great news!  We’ve finally got the Papilio Pro and the RetroCade Synth in stock here at the Gadget Factory store.  To celebrate, we’re going to make you a deal.

Starting today, and only for a very limited time, we’re offering TWENTY BUCKS off the Papilio Pro and the RetroCade Synth when purchased together. Call it a bundle!

This offer is only available at our own storefront, and is valid while supplies last.  These will sell out fast at this discounted price, so get yours now!

Keep in mind that we offer fast and affordable domestic shipping as well as low-cost international options.

Here’s a link to the bundle in the store for your shopping convenience.

Happy hacking.

Some Thoughts On Mixing Digital Audio

Mixing audio in the digital realm has some inherent limitations.  These limitations become more pronounced the less data there is to work with (i.e. low sample rates etc.). We found an article by software developer and author Viktor T. Toth that addresses some of these issues.

In real life, when you hear audio from two sources simultaneously, what you hear is the sum of the signals. Therein lies our problem. If you hear a group of ten people singing, the result will be louder than the singing of one person. A giant choir of a thousand will be even louder. A hundred thousand people singing an anthem in a sports stadium can be outright deafening. The point: there is no upper limit; the more voices you mix, the higher the amplitude.

With digital audio, we have a limited dynamic range. Let’s say we use 8-bit sampling; that means that every data point in the audio stream is a value between 0 and 255. When we add two such values, the result may be anywhere between 0 and 510, which simply doesn’t fit within the allowable range of 0-255.

Mr. Toth’s article goes in to detail about why using normalizing as a mixing method doesn’t hold water, and how using it on low sample-rate signals is an especially bad idea. The author busts out some math to dive into a couple of workarounds for mixing low resolution audio without normalizing, and he’s got some pretty good ideas here.

Great read – be sure to check out the full article at Viktor’s site.  If you’d like to chime in, feel free to do so in the comments.

(via vttoth.com)

RetroCade Hardware Guide and User Guide Available Now; Final Hardware Launching Soon!

In anticipation of our final RetroCade Synth hardware launching within the next couple of weeks, we wanted to take a minute and point everyone in the direction of the updated RetroCade Hardware Guide and the RetroCade User Guide:

These webpages are “works in progress” at this point, but are being updated constantly – so check back to these pages *often* for the very latest.  If you’re interested in FPGA audio synthesis at all and are unfamiliar with our RetroCade Synth, make sure you check out the Retrocade home page for a great overview of the product, some video of this little bad boy in action, and some general tech specs.

So get your knowledge on!  And get ready for some hackable chip-tune synthesis action with the RetroCade Synth by Gadget Factory.

Additional links:

Questions?  Ideas? Flattery?  Hit us up in the comments section, and stay tuned to the blog here for all your RetroCade developments.