system-wide parametric equalizer (iOS)
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The EQE source is broken down into two parts:

  • Lua (~60% of the codebase)
  • Objective-C (~40% of the codebase)

This repo contains all of the Lua code. The Objective-C code is closed source. (See reasoning below)

How to make use of this code

This repo is exactly like what you would find in /var/tweak/com.r333d.eqe/lua on your iOS device. If you want to make changes, just edit the files there, and then run this command to load the changes:

killall -9 eqed mediaserverd backboardd

For an error log, install deviceconsole, connect your iOS device to your computer via USB, and then run this command:

deviceconsole | grep "EQE Log"

High level overview of codebase

I'll explain the folders.


The entire app (other than the equalizer page) is in Lua. The forum browser, update logic, playback history, markdown parser, even the bootstrap code is in there. To get a high-level overview I'd look at app/main.lua, and everything in app/page/.


The command-line ncurses "GUI". Code could use some improving, but it's a pretty small codebase. If you wanna mess around with stuff I'd recommend starting here.


Common libraries. This is where you can pilfer code from. Includes an Objective-C to Lua bridge, sqlite library (written by me), cmark library (written by me) and json library.


High-level equalizer manipulation stuff. core/filter is where you'll find the code for the different types of filters, core/preset.lua is preset saving/loading logic.


Code for the playback history tracker. Includes the logic for posting to scrobble is called whenever an app plays a song. This is where you'd put the code for an alternative scrobbler.


Convenience scripts you can run manually. Imports Winamp presets and that kinda stuff.


High-level code for raw audio manipulation.


Code for the frequency response curve in the equalizer UI. If you want to change its color or something this is where you'd do it. This is also where I hope for the equalizer UI to go once the LuaJIT bug is fixed (explained below).

Objective-C stuff that ISN'T in this repo

  • The equalizer UI itself, other than the frequency response curve (LuaJIT gets buggy when injected into SpringBoard, so for activator integration, I had to write this part in Objective-C)
  • MobileSubstrate hooking logic (needs to be fast)
  • Inter-process communication (multithreading is a nightmare in Lua)
  • Biquad filter logic (needs to be fast)
  • Activator / Flipswitch boilerplate (I'm pretty sure nobody cares about this code)
  • cycript-esque REPL (multithreading is a nightmare in Lua)


  1. I plan on continuing development far into the future. For me, disclosing all of the source has no pros and is nothing but potential cons. For all I know, some Chinese company might steal this and run off with it into the sunset, like the Citra 3DS emulator.
  2. I want to discourage Objective-C contributions. Lua code is much easier to extend and maintain.

If people start contributing to (or the community substantially benefits from) the Lua side of things, I will open source the Objective-C side as well. But for now, I don't want to risk getting burned. I hope you will understand.

Pull requests

I don't know if I'll accept pull requests. This is mostly just a mirror. Better to ask / post code on the Discord chat or on the forum first.