PD400X is a dynamic microphone, relatively insensitive, the recommended distance is within 15CM
Please speak according to the direction shown to avoid the microphone not picking up the human voice
Using USB mode: Please check whether the microphone gain knob is in a reasonable position and whether the computer is using the device PD400X
Using XLR mode: please turn up the gain knob on the sound card, please check if the gain of the sound card is enough to push the microphone