If one does not hear the Athaan at the Musjid, is it still obligatory to attend the Musjid or Jamaat Khaanah for Salaat?

Answer

Performing Salaat in jamaa't at the Musjid is not dependent on hearing the Athaan. Whether you hear the Athaan or not, it remains Waajib to go to the Musjid for the Fardh Salaat unless one has a valid reason for absence.