Is congregational prayer obligatory for one who does not hear the call to prayer at home with his family, or is it waived, and is it permissible for him to pray alone?

Congregational prayer is obligatory for free, adult men. It is valid to perform it anywhere; a mosque is not a condition for it, nor is hearing the call to prayer.

If you do not pray in the mosque in congregation, you must pray with some of your family. If you pray alone while congregational prayer is obligatory, you incur sin.

As for someone who is far from the mosque and does not hear the call to prayer except through a loudspeaker, he is not obligated to attend the mosque and may pray with those with him in a separate congregation. And whoever endures hardship and attends the mosque, his reward will be greater.