Tips: USB speakers, we recommend you use a computer USB port is directly powered speakers, speaker for longer life. If you have to use USB power adapter (cooked said charging head) is powered speakers, it must choose the regular manufacturers 5V1A charging head (must be current enough 1A, charging head on the market, although many labeled 1A, but actually only five-six mA); when the speaker volume down if you caused the loudest, appears sound off, it means you have insufficient power supply charging head, then easily burn the internal speakers circuit with caution!