Amazon.com: RUIZU MP3 Player with Bluetooth 5.0, 8GB Portable Music Player for Kids, Digital Audio Players with FM Radio, Voice Recorder, Video Play, E-Book, 80 Hours Playback, Support Micro SD Card Up
MP3 Volume Changer – Increase or Decrease MP3 Sound in Seconds
How To: Increase And Decrease The Volume Of Audio In Audacity - YouTube
How to Increase or Decrease Audio Volume in Audacity?
How to Increase or Decrease Audio Volume in Audacity?
How to Make MP3 Files Louder? (Increase or Decrease the MP3 File Volume)
What's the loudest MP3 player I can get (born hard in hearing so I don't need the lecture of ear damage, certain headphones, etc.)? - Quora