Portable Voice Amplifier, Blutooth Waistband Voice Amplifier Rechargeable Speaker With Personal Mic-Black

Put the microphone in front of your mouth to get the maximum amplification effect. ^
Do not whistle: keep a certain distance between the microphone and speaker, preferably facing each other. ^
The best way is to put on a microphone headset, hang the amplifier speaker on your waist, turn it on and gradually increase the volume as needed.^