const backgroundAudioManager = wx.getBackgroundAudioManager()
    backgroundAudioManager.title = '语音提醒'
    backgroundAudioManager.epname = '语音提醒'
    backgroundAudioManager.singer = ' '
    backgroundAudioManager.coverImgUrl = ''    
      backgroundAudioManager.src = 'https://xxxxxxxxxxxxxx.mp3';

　　​​https://developers.weixin.qq.com/miniprogram/dev/api/media/background-audio/wx.getBackgroundAudioManager.html​​

基础库 1.2.0 开始支持