Resonance

My roomie (anonymity preserved) observed a strange phenomenon with the BPL radio at home playing Radio Mirchi.. Just out of bath, he suddenly got a crazy idea to stick his neck out (literally) near to the speakers. As he did that, the sound suddenly amplified and when he pulled back, the audio came back to normal. Bringing his head near the radio somehow apmlified the audio.

When he asked the Communication Engineers (your truly being one..) for an explanation for this strange event, we identified and concluded that it was a well observed effect. With all due respect, we clarified thus:
'When an empty cavity is brought near an oscillating source it resonates with the source, amplifying the signals'.