Battery drain on phone when listening on laptop application

[mammoth200]

So this is a bit odd.

When I'm listening to music on my laptop, the player links to my mobile (so I can only listen on one device at a time, which I understand) but in the process it's completely obliterating my mobile battery life while the phone isn't in use? Is there any way to stop this from happening? I've tried force closing the app on my phone, disconnecting from wifi only means it starts using data instead to maintain a constant connection.

Theres a background process called Audioserver which appears to be responsible for using 20% of today's battery life of an hour or so. This is on a Samsung Galaxy S7, running the most up to date software both on the phone and the spotify app. 

Help please!