in one narration Sayyidina Rasulullah sallallahu 'alaihi wasallam said to his sahaba 'alaihimur ridwan that i have just heard a noise from the sky. this shows the power of the hearing of sayyidina Rasulullah 'alaihis salam because the sky is thousands of miles away. and imam qurtubi writes that Rasulullah sallallahu 'alaihi wasallam did not even specify which sky (eg. 1st or 7th) so our master 'alaihis salam could have meant even the 7th sky. and the power of hearing increases in the grave because if you bury someone alive 7 foot deep, he will not hear your footsteps or salam but ahadith show the dead when he is buried can hear footsteps and salam.