Very Quiet MuseScore Website Playback
I've posted a song on MuseScore, but the playback is very quiet. You can't hear it at full volume unless you press your ear up against the speaker. The playback sounds perfectly normal in the software.
https://musescore.com/user/18995521/scores/4927744
Comments
Hmmm... I'm guessing that you didn't use the compressor setting in the Synthesizer window?
Here's how to compress it. https://musescore.org/en/handbook/synthesizer#sc4
Once that's done, save the Audio Changes to the Score, then Upload it as an "Updated" Version.