Enabling or Disabling Speakers in Windows 8 is very easy. You can enable or disable speakers because of many reasons. I've disabled them in many cases. I've done it mostly when i was recording few screen casts. You might want to do it for any other reasons. Here's how you do it.

Step 1:
You can observe a "Speaker /Volume Icon" in your Notifications Area in Windows 8. Now Right Click on it.

Step 2: Select "Playback devices"

Step 3: Once you click on it, It will show you all the devices which are connected to your computer. It can be your Headphones, Other Audio Devices etc.

Step 4: Now Enabling or Disabling Speakers is very easy. Since they're already Enabled, We'll disable them first. To make any Modifications, select the device and click on "Configure"

Step 5: Once you click on Properties, You'll find the option to enable/disable the speakers in the "device usage" tab.

Step 6: Select "Don't use the device" and click on "Apply".

Step 7: As you can see in the below image, the devices are successfully removed.

Enable Speakers

Step 8: Now Let's Re-Enable the Speakers. To do it, Navigate to the "Playback Devices" Once again as show in the Step 1 and Step 2. Since All the devices are disabled, You'll see the below screen.

Step 9: Now, Right Click on the Area where you normally see the devices and select "Show Disabled Devices"

Step 10: Once you select the option, You'll see the disabled devices as shown in the below figure.

Step 11: Now Right Click on the Device, You would like to Re-Enable and click on "Enable" as shown in the below figure.

Your Speakers will be Re-Enabled once again.