The sound may become low in the following cases. This is not a malfunction.
When the built-in battery is running low and the CHG (charge) indicator flashes slowly, while the speaker is being powered by the built-in battery only.
When the built-in battery is running low as a result of using the speaker at a loud volume for a long time even if the speaker is connected to an AC outlet via a USB AC adaptor (commercially available), or connected to a booted computer.
If the sound becomes low while in use, follow the procedure below.
Turn off the speaker.
Charge the built-in battery sufficiently.
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