Root Volume Mixer +Booster/Mic is a free Android app developed by Piereligio. The app is designed to tweak the volume of the speaker and microphone of your device. It is especially useful for those who find their speaker or headphones too loud or too quiet or those who want to record gigs or any loud event but their microphone crackles, destroying every audio detail. The free version of the app only lets you tweak the speaker.

It is important to note that the app requires root access, and if you don't know what root is, you should not try this app. Additionally, the app works by editing a system file, mixer_paths.xml, which is different between devices. Therefore, results may vary between devices, and some values may not show up, or the app may not work at all.