Rockit firmware 1.12 is available. The changes are mostly limited to MIDI. I’ve implemented a soft MIDI Thru. Messages not intended for Rockit, meaning on a different channel, are passed through to the MIDI Output. The MIDI channel can now be changed. To change the MIDI channel, hold down the Select button until the display starts flashing. Then, use the Save and Recall buttons to change the MIDI channel. Finally, hold down the select button until the display stops flashing and that’s it. Otherwise, I fixed a bug that caused the audio to stop when the arpeggiator was running and drone mode was entered. That’s about it. Some other transparent changes were made for an improvement in the number of clock cycles required to perform various tasks. Have some fun and let me know if you find any funny business going on. Download the hex file here.
I developed a presentation as part of my Sprockit workshop. I think it’s a pretty clear presentation of wavetable synthesis and that it clearly shows how aliasing happens and how to avoid it. I’ve often found that it is difficult to find this type of clear and simple explanation of fundamental synthesis concepts that is particularly useful for the DIY Synth community. So, click through for some learning…
Arran over on buildmusicthings.com put a nice explanation of how to build Rockit’s source code and get it uploaded to Rockit on OS X. Check it out here.
I’ve been hard at work on Rockit’s firmware and am proud to put out Version 1.1. There are a number of improvements, bug fixes, and a new feature. I’ve also made a few adjustments/hacks to resistor values which greatly improve Rockit’s sound. Click through for a list of the software and hardware updates. Continue reading
The Rockit case is finally finished. I got the third and final prototype of the Rockit case in, put it together, and did the happy dance. I’m going to make some small adjustments for the production order, but nothing that will require another round of prototypes. I’m going to put up the case for pre-sale today. I need to hit a threshold of about 50 orders in order to buy it. The lead time from the laser cutter is three weeks, so these should ship in February. The cost will be $50. Click through for more pictures. Continue reading
Check out this Rockit assembly time-lapse video! Big thanks to its maker, Siempre La Luna.
It was my intention to have the case ready for sale by now but events have intervened. I managed to get the design done and ordered but there were some snafus at the laser cutter and what was delivered was not what was designed. I’m getting another set made but I couldn’t get it before the holidays, so it’ll be done in January. I did get to see how the two-tone material is going to look and it’s gonna be officially dope. I know it’s been a while but this case is going to be worth the wait.
I’m working on a software update for Rockit to fix a few bugs and to improve some features. I’ve got a feature in mind to add as well, but I’m going to keep it a surprise til it happens.
I’ve got another thing in the works as well and I’ll probably announce it in the next week.
Cheers and Happy Holidays.
Here’s the new faceplate drawing! My wife has been hard at work. If you can’t tell, we decided to take the design in a decidedly less boring direction. I want Rockit to look like nothing else and I think we’ve achieve that. The case files are heading to the laser cutter as we speak. Hopefully, I’ll get the prototype back by next week. This faceplate will be cut from two-tone acrylic, which is black with white material sandwiched on the back. The laser blows away the black material to reveal the white below making everything entirely legible. Stay tuned!
I’ve spent a fair amount of time detailing the hardware that Rockit uses for it’s Voltage-Controlled Amplifier. It’s a transconductance amplifier-based design and you can read about it here. I haven’t, however, discussed the software behind implementing the envelope generator. It ends up being more useful than just controlling amplitude. The same envelope generator code works for the filter envelope too. I didn’t end up using exactly the same code, but it could be made entirely modular, taking some basic inputs like timing and parameter data and returning an appropriate value for an envelope. Let’s just focus on how to code an ADSR envelope for now. If you’d like to get the source code for Rockit, please download it from Rockit’s Sourceforge Page.