HDMI cables are capable of transmitting both video and sound to an external display. This is a fantastic feature if the external display is equipped with speakers, but if if speakers are not present, no sound will play. The simplest way to test if this problem is occurring is to do as follows:
With the external display disconnected from the computer, open EEGer and run a replay session. When rewards are earned, audio feedback should be heard from the computer if it has speakers (such as a laptop).
Close EEGer and connect the external display to the computer.
Run a replay session - if no sound is heard when rewards are earned, audio feedback is being routed to the monitor instead of to the computer's speakers.
To correct this problem, follow the steps below:
With the external display connected to the computer, locate the Speaker icon on the computer's system tray. This is the area of the taskbar which usually has the date, time, and a small chevron - by default, this is on the taskbar in the bottom right corner of the screen. If a speaker icon is not visible, click the chevron to see an expanded list.
Right-click on the speaker icon and select Open sound settings from the context menu that appears. This should open the Windows Settings app.
On the right side under Related Settings, locate and click Sound Control Panel. This will open up a new, smaller window.
On the Playback tab, you should see a few options listed. These should include Speakers and another option for the external display (typically a monitor icon with a green indicator beneath it).
Right-click the Speakers option (typically Realtek High Definition Audio) and select Set as Default Device. Once this is done, a green checkmark should appear on the bottom-right of Speakers icon.
To avoid Windows Updates from switching the sound back to the external display, right-click the external display and select Disable from the right-context menu. This should cause the icon to appear grayed out.
Click Apply and then OK at the bottom of this menu.
Attempt to run a session - when earning rewards, sound should now play from the computer's speakers.