No sound in IE but sound in Chrome?

I have a Lenovo thinkpad i7 64 bit on 8.1 pro.

I have a monitor hooked up to the laptop via HDMI for dual monitors.

When I play a video (on youtube or whatever) in IE there is no sound but the volume control shows it going up and down as if it is working.

When I play in Chrome, it is fine.

Why would there be sound coming from one browser, and not another?

If you have HDMI connected the PC automatically changes the default audio playback device to the HDMI audio. If you want PC audio you must manually change the default audio playback device to the "Speakers". Windows only allows one default audio playback device at a time.

I don't have Chrome so I can't say what options it has.