wtf is walkman-tuning-guide?

Walkman Tuning Guide is a bilingual, Chinese and English, toolkit for people who own a Sony Walkman A, ZX, or WM series music player and want to apply custom headphone sound correction beyond the player's built in equalizer. These players share an audio chip called the CXD3778GF, and the project's authors studied the firmware and kernel source of specific models to figure out how that chip's deeper tone correction tables actually work. The core idea is to take a parametric EQ profile from AutoEq, a site that publishes headphone correction data, and convert it into a tone table the chip can use directly. That table is made of five chained filters, and the project's Python tools translate the AutoEq numbers into the exact parameters the chip expects, then help write that table onto the device over ADB, the Android debugging tool used to talk to the player from a computer. Deployment differs by model family. On the A series, testing showed the table can be written directly to a system file exposed by the stock firmware. On the ZX and WM series, the stock kernel does not automatically reload the chip's memory with the new table, so the project also builds and installs a custom kernel module that forces the update, along with a script to make that happen automatically every time the device boots. Scripts are also provided to restore the original stock tone table and remove the custom module. The README repeatedly and explicitly warns users to back up their device before starting, since the process involves ADB unlocking, writing to system files, and in some cases installing a kernel module, and it points to a separate community backup and restore tool. The author states everything is provided as is with no guarantee it works on every device, and takes no responsibility for bricked devices, data loss, or hearing damage.