A heavy silence/atmosphere
Definition 1 of 3
Pro Tip 1/3Intensity Indicated
The phrase often suggests an emotionally charged situation where silence amplifies the tension. 
After the verdict, a heavy silence engulfed the courtroom.
Pro Tip 2/3Expectation Felt
Used when people are anxiously awaiting something, making the quiet feel even more profound. 
As the clock struck midnight, a heavy silence loomed, marking the old year's end.
Pro Tip 3/3Not Literal Silence
The 'silence' can sometimes be metaphorical, highlighting its presence amidst noise. 
Even with the music playing, a heavy silence filled the air between them.