Sound fades on embedded videos

I'm having an interesting problem. I have a pair of powered JBL speakers plugged into the headphone jack on my Macbook Pro. When playing most Youtube videos but mainly when playing any embedded video, the sound is fine for about 70 seconds. Then, the sound slowly fades over the next 20 seconds until it's completely gone. I then have to power off and power on the speakers and the process repeats itself. Any ideas on what could be causing this? BTW it's a Macbook Pro 2017