Control optical audio volume within OSX
No sooner do I write an article complaining about not having the ability to change the sound volume while using optical audio on OSX do I find an easy fix. By harnessing the application Soundflower you can easily circumvent this lock. First download Soundflower from their google code page. Next change your default audio output to Soundflower (2ch) as seen below.
Next you are going to open the Soundflowerbed located in your Applications folder, it is inside the folder Soundflower. Now you have a menu item that looks like a flower. Click on the Soundflowerbed icon, go down to Soundflower (2ch) and make sure both channels are enabled and check the output to Built-in Output. That’s it, you’re finished. Now you can adjust the volume from your keyboard and from your receiver. Why Apple has this locked is beyond me because this method works fine with no audible difference. Here is an image showing how my settings look.
I had to adjust the volume a couple of times for my output to start working so if you don’t hear sound right away make sure you try to change the volume first. Also this application requires you to reboot so save your documents before following this guide.