The Problem
You want to mess around with digital audio effects—think phasers, flangers, delays—without diving into the bottomless pit of hardware or fancy DSP voodoo. Maybe you just want to hear what happens when you slap a basic IIR filter on your guitar signal and don’t feel like reading textbooks or shelling out for yet another plugin. Most open-source audio effect repos are either bloated or written for hardware you don’t own.
What This Does
AudioNoise is a grab bag of "toy" digital effects, mostly written in C/C++. The root directory is where the action is: files like echo.h, phaser.h, and flanger.h each implement a classic effect, all in the "single sample in, single sample out" style—no fancy FFTs, just basic delay loops and filters. Want to see how an all-pass filter works? Crack open discont.h or biquad.h. The process.h file threads it all together. There’s a visualize.py script for plotting audio signals, but don’t expect matplotlib wizardry—it’s more "I Googled this" than "I engineered this".
Testing isn’t ignored: the tests/ folder has simple C files (lfo.c, sincos.c) for sanity checks. Makefile handles the compilation, so you’re not stuck fiddling with build systems or cmake nonsense.
Real-World Use
Say you’ve got a raw WAV file and want to slap a digital flanger on it. You’d grab the code from flanger.h, run your samples through the flanger_process() function, and output the results. Want to see how your tweak changes the signal? Fire up visualize.py and plot before/after. The workflow is basically: hack a header, compile with Makefile, check output with Python. It’s simple enough to bolt onto a microcontroller project or use as a reference for your own pedal code.
The Bottom Line
AudioNoise is refreshingly honest: it’s for learning and tinkering, not for pro audio. The code is straightforward, with zero bloat and just enough structure to keep you sane. If you want fancy features, look elsewhere. If you want to play with basic digital effects (and maybe laugh at some comments), this is your sandbox. Perfect for hardware hackers and DSP newbies; overkill for anyone just wanting a ready-to-go pedal plugin.