Android UART Audio Equalizer Module

I’m adding a UART-based audio path to the Android build of my product and now need the equalizer layer. The goal is strictly audio processing: the app (or library) must intercept the UART audio stream, apply EQ and other effects in real time, then pass the processed signal back to the system.

Core requirements
• Equalization controls – band-based sliders plus overall gain.
• Optional audio effects such as bass-boost or reverb that can be toggled on/off.
• A dual-preset system: ship with a set of predefined curves (Rock, Pop, Classical, etc.) while also giving users full freedom to create and save their own custom EQ profiles.

Please keep the code clean, documented, and compatible with recent Android SDK levels. I will test with both physical hardware over UART and an emulator loopback; acceptance is when I can switch between factory presets, store a custom curve, and hear the changes instantly without glitches or latency artifacts.