The sound of Win7 is suddenly big and small

How my voice is loud and small, the system is Win7, before using XP has been good. After using Win7 for more than a week, the sound of the sound is loud and small. For example, music is being played, and then a friend is suddenly on the QQ. There is a sound like knocking on the door. At this time, the concert suddenly becomes very small. The knocking sound of QQ is that after the normal university is knocking on the door, the music will return to the normal volume. (Forum 1d3d)

[Gong Master]: This is actually not a problem at all, but a design of Win7. When the system checks the network communication activity, it will automatically reduce the volume of all other sounds. You can go to "Control Panel" and "Sound", select to the "Communication" panel, change the option to "Do nothing", so that no matter how QQ is online, the volume of the music played by the system will not change.

Change to "Do nothing"