Recently I tested every audio addon, that was updated during the last 12 months. This one belongs to the „600% Sound Volume“-family, which is a solid choice since a long time. Among this family there is a lot of back and forth: The original by Aliaksandre and the first privacy orientated fork by1fexd are gone now. The latter has two legit sucessors: The addon by Savva, wich is under rough recontruction, and LEFRIENDS‘ conservative clone, which is not open source, but the only family member to work on Soundcloud. So, make your choice, but be aware of what‘s happening next!

it actually works on soundcloud!!!!!! and it just works all around, super good

I thought this extension was gone for ever! It's finally back?!?!?! Its so useful especially when the video's audio track is very soft and slow!!