Increasing the volume to 150% on QuickTime Player

If you do not have external speakers or headphones, and you need more volume from the QuickTime Player, do the following to add up to 50% more volume.

Hold down the Shift Key on your key board and at the same time
Click on the loudspeaker icon (red arrow)

You will see an extended volume control with and extended range that will allow you to increase the volume to 150%.