The noise is generated by inserting the microphone

Speakers usually use when everything is normal, but after inserting the microphone, the speaker will immediately generate noise.

Microphone and sound card connector line does not use shielding line or shielding line grounding, external high-frequency interference signals by the microphone input string will cause noise. If you unplug the microphone, the noise will disappear. If it is to connect the microphone to bring the impact of the use of shielding lines without the need for shielding. If the shielding line has been used, you can use a multimeter to check the outer layer of the shielding line even farmers shielding line, to see if there is a chassis connected, to eliminate the reasons for the poor grounding. In addition, from the sound card to the active speaker signal line should also use shielding line and grounding.