This blog post will explain how to specify no soundcard in QEMU. A virtual machine that is going to be used as a server usually has no need for sound input and output. The -audiodev flag is used to setup an audio interface for QEMU. Since no audio interface is going to be used, the id and driver is set to none. Whenever the virtual machine is started up, there will be no audio input or output.

-audiodev id=none,driver=none

The Windows version of QEMU was used to write this blog post.