I am not sure if i understand the question correctly but i guess you mean how you can add a sound card to a vm from the ESXi host. Maybe the link below can help you:
Try the below on ESXi server
SSH into the Host the VM is located.
> Navigate to VM folder.
> Edit .vmx file with vi editor and add below lines in the end of the file.
sound.present = "TRUE"
sound.virtualDev = "es1371"
sound.fileName = "-1"
sound.autodetect = "TRUE"
sound.startConnected = "TRUE"
> Save and exist the file.
> Power On the VM.
> On summary of the VM you get the message:
Cannot connect the virtual device sound because no corresponding device is available on the host. Do you want to try to connect this virtual device every time you power on the VM?
> Select yes
> Launch the VM console and validate the changes to the device were successful.
Do not add these 2 lines for ESXi, as the VM fails to power ON if added:
sound.virtualdev = "sb16"
sound.virtualdev = "hdaudio"