Very slow sound
Is your model ZB601KL and firmware version WW-17.2017.2004.424?
Do you mean the volume is low? Could you tell us whether this appears on wired earphone/bluetooth headphones/phone's speaker?
What app/app version are you using?
Please show us a screenshot of the volume level.
Do you have a music link you can provide as an example? Could you describe in more details about the sound problem?
Thank you. 🙂