Do something every x minutes without trigger

I have a JBL bluetooth speaker hooked up to a wall mounted tablet, but unfortunately, the speaker turns itself off if it doesn’t get any input for 10 minutes - even when its plugged into a power source.

So wanted to play a barely hearable sound every 9 min, in order to prevent it from turning off.

Here’s what I tried:

- alias: sound_ping
  trigger:
    - platform: time
      minutes: '/9'
      seconds: 00
  action:
    - service: notify.notifier_name
      data:
       method: 'alarm'
       message: 'FILE1'

LANouncer is running on the tablet and the file is stored there, btw. I actually named notifier “notifier_name”, in case you’re wondering.

Nevermind, figured it out. My spacing was all fucked up