Chris Anderson @chrisanderson1973@librem.one

Stick practice today! Starting to learn pieces from Greg Howard’s “Tapping into Bach”. Minuet in G is the goal, relatively soon.

It looks like Analog Devices has a good number of products that are obsolete, or headed that way. So, in order to head that off a little, I looked around and found that newer designs are using the SHARC processor series. The SigmaStudio IDE has been updated, as well. I had to order a new kit in order to access newer features and being able to create custom DSP blocks. This is the new SigmaStudio IDE.

Analog Device's BF706 reference design bring-up: The audio pass-through and filter demo's worked great, and this platform is way ahead of the STM32 platform I used last year. This looks like a good module to use for prototyping distortion, reverb, filters, octave, etc. We'll how it goes.

I’ve been considering the hardware-based effects idea again; and, while I cannot locate any SHARC Analog Devices development kits, there is an older (and trustworthy) platform called the BF706 (Blackfin). So, my plan, at the moment, is to try getting the schematic for that design and adding it to the iMX8 reference design. Much more to come.

https://www.analog.com/en/products/adsp-bf706.html#product-overview

The composer app effort is continuing. I've cracked the Apple Audio Unit code, and now I see that there is an easy path to integrate Audio Units into my own apps. This is going to be a Mac and iPad app, I think.

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Working on AudioUnit Extensions for Mac and iPad. Turns out, it is kind of fun. I am building a synth module (which would be a re-imagined AnaddrSynth) for a new DAW I am working on.

Another post on this new direction: I'm building a performance app from Mac and iPad. It may be more like a digital audio workstation, and it may even be more like a lot plugins placed together, for software like Logic Pro on iPad.

Another swing of the pendulum, and I am looking into macOS/iPadOS apps once again. I have a much better grasp of Core Audio this time (versus 2011-2014 and 2018), and I will probably refactor AnaddrSynth completely and, of course, introduce a new app.

Ona plane flight, coming back from CA, I thought about the interview with Markus Reuter and his process for creating music. This gave me a fairly grand idea, and mostly because I have no real idea how he put together his workflow…..So, it looks like I am building a looper-DAW.

Cool work day - digging into how C++ works.... Untangling dynamically linked libraries and setting class pointers.... Basically, exposed variables, per name, need to match in terms of data types. I just overlooked the obvious. :D

A new direction - sorta.... I am looking into making a looper for recording audio. #problemsolving #reinventingthewheelprobably

A quick update: The ALSA audio project for Linux has a utility called alsaloop, which provides an audio loop back through “capture” and “playback” interfaces. On the Toradex Apalis iMX8 platform, using alsaloop, I was able to play an instrument in a loopback configuration with an analog “line in” and a headphone jack. This is a huge deal, because it allows for an analog-in to digital to analog out path, and a great embedded device for building a complex effects processor!👍 More work to follow!

More work with the iMX8 platform to try and mold it into an audio effects and/or digital audio workstation. Some quick tests recently have shown that USB audio is a little slow on the iMX8, in that the set up has a noticeable delay and that the USB interface doesn’t quite keep up. That is, at least with the port audio stack. So, the other option is to run analog in/out on the board, and have it work more like a deluxe effects box. The analog in sounds great. An analog out test is next.

Still working on Linux audio on the Toradex iMX8 platform.....

Today, I made a first stab at a recording app for the coming iMX8-based DAW system. The audio recording/playback set up is the very fist step. Today, I was able to record some improv off my Ibanez!

Nice bit of audio work and embedded Linux work tonight. I managed to have the Linux sound framework working, taken from a Yocto build. It was enough to instantiate the audio card interfaces, including USB audio, and even run audio playback through HDMI and a DUET USB audio interface.

More work on my power amplifier design tonight. I added an auxiliary output that is available after any gain/distortion and reverb, and before the output (power) stage.

Looking into new DSP platforms, rather than the very minimal STM32F series I researche di nthe fall.... Starting with the Cyclone V FPGA platform, using the Quartus Prime Lite Edition.

I've gotten as far as designing the printed circuit board, including the power supplies and power amplifier stage!