Audio quits after sleeping Macbook Pro with external speakers

I have a 2015 13" Macbook Pro and recently upgraded it to El Capitan. I've started using it with the lid closed, an HDMI connected monitor, and wireless Apple keyboard and mouse. I also have an pair of external M-Audio AV-40 speakers connected to the audio jack on the Macbook. This setup works fine however every time I sleep the Macbook and wake it up the audio quits working and shows as grey'd out in the menubar. If I simply unplug the speakers and plug them back in audio starts working again and it will be fine until the next time I sleep the Macbook.

Has anyone else seen this and come up with a workaround or a fix?