

Audio can be switched form notebook speakers to HDMI to DisplayPort and the flash video plays fine. However 24 bit 96 kHz gives no problems with sound or slow motion video when unplugging external monitors.

Only a system reboot would bring the sound back with 24 bit 48 khz and 24 bit 44.1 kHz. In this setting, plugging the monitors back in would not bring the sound back, enabling, disabling would not help either. In addition, flash video playing in IE 11 would change to slow motion (50%) and the sound would go away until I switched sound output back to notebook speakers.

At 24 bit and 48 kHz or 44.1 kHz the sound would fail (with meters moving) when one of the external monitors was unplugged. The issue was fixed for me after to switch to 0 Hz audio, because in 16 bit audio would only show the meters moving but no sound output through HDMI or DisplayPort.
