DSP and Sigma Studio

DSP, short for Digital Signal Processing, refers to the digital processing of audio signals. In Sigma Studio, the Analog Devices application, you can perform various processing operations using a whole battery of nodes, from delay and frequency modulation to crossover and bass boost.

It works with visual programming, meaning you create a schematic using building blocks. In my case, I found a sample project by the enthusiastic audiophile Hendrik from https://hs-sound.de. During my previous attempts to run the program on the Tinysine7800B, I got no sound, which was caused by the lack of inputs correctly paired to the Bluetooth input via I2S.

The Tinysine is connected to a Windows laptop (thanks to Bambi Medical) using a JTAG programmer (USBi). You can then press "Link, Compile, Download" and modify the program from RAM memory in real time.

This defines a crossover frequency for the audio signal, the frequency at which the woofer rolls off and the mid-range satellites begin. This prevents signal overlap and unwanted resonances and cancellations. The woofer reproduces the bass frequencies from the left and right signals, while the mid-range satellites reproduce the midrange and high frequencies in stereo.

Once the program is working properly, you can save it to Read Only Memory (E2PROM) so it's loaded upon power-on. This process takes place before the amplifier is installed in the woofer.

Finally, I'd like to thank Hendrik for his great YouTube video about Sigma Studio and the Tinysine 7800B. And for making the project available on his website.

See you next time!