This has been posted and closed many times:
But I think it is really important, especially on Android and I wanted to resubmit it and publicize it(a lot). Even if you LIKE Audio Ducking, Please vote for this!!! It's only an OPTION for crying out loud!! If you like this idea please share this post with your Spotify using friends and family!
Update: Idea has been reposted here.
Updated on 2019-08-07
Your idea was submitted a while ago and unfortunately didn't receive the amount of kudos needed to stay active in the ideas board (100 Kudos per year).
In order to keep the Ideas Exchange clearer I'll close this idea for now, but this doesn't mean Spotify rejected this idea.
If you think this is an idea which needs to be implemented, you're welcome to post it in a slightly different form :)
Have a nice day!