Hi,
I've pushed the source for a Teensy 4.0/audio daughterboard based DSP audio processor up on github:

https://github.com/grahamwhaley/DSPham

The main role of the processor was for noise reduction for amateur radio reception. It also gained some CW decoders as well.
Details are on the github page.

Much of the code was borrowed from the Teensy convolution SDR - so, /cc @DD4WH et. al., and kudos for the code :-)
Other code was taken from the $19 DSP filter project, and a number of other sources - see the github page, or peruse the LICENSES file etc.
And of course, kudos to PJRC and @Paul for the hardware and the audio library, which really gave the project a huge 'leg up'.

An article detailing the project was published in the RSGB RadCom magazine today.

Graham
M7GRW