When I am using headphones (blueetooth or wired) the sound is pretty low even on 100%. When I am using those headphones on PC or mobile, the sound is high enough. Is there some app for boosting my sound? I know that I can boost the sound from KODI app, but i would like to increase it for my streaming apps like Netflix, HBO MAX, Disney+. I know I can play those apps from KODI addons, but not all of them have 4K support.
Like a year ago someone asked about something similar in the Nvidia Shield subreddit due to having hearing loss. I will copy/paste my answer from back then. It should work on any Android TV device.
Cheapest/free method? An app called "Speaker Boost Volume Booster Pro".
It's meant for phones, but it works on the Shield. You will just need to sideload it. I specifically use an older version (3.0.15) I found online to sideload and it works great.
You will just need to set it up initially using a mouse (or the official Shield phone app) because it's not remote-friendly.
There is a setting to run the program on boot, but it doesn't seem to work on the Shield. So if you reboot your Shield, you will lose the boost until you open the program again. Luckily it does remember your boost settings, so you only need to use a mouse for the first set up.
It boosts ALL audio. Whether it's bluetooth headphones, regular headphones, tv speakers, whatever. Your volume will be boosted. It allows you to bypass audio limits, so you have to be careful and not boost too high. There's a warning that lets you know anyway. Not just because it can damage your hearing, but you could potentially damage your speakers.
It really works well. I do not suffer from hearing loss, but my pair of bluetooth earbuds don't seem to get very loud when connected to the Shield for whatever reason. With the program running at 20% boost, it allows me to hear everything so much better through the earbuds.