I have a Dell 2407WFP and it made a sound, although I had to maximize it. I had a Dell 2007FP rotated to portrait and didn't hear anything - rotated it back to

I have a Dell 2407WFP and it made a sound, although I had to maximize it. I had a Dell 2007FP rotated to portrait and didn't hear anything - rotated it back to landscape and I heard the sound.