There were two hundred and twelve whose business it was to keep the doorway. These were listed by families in the country places where they were living, whom David and Samuel the seer put in their responsible positions. Verse ConceptsSeersVillages

And David gave orders to the chief of the Levites to put their brothers the music-makers in position, with instruments of music, corded instruments and brass, with glad voices making sounds of joy. So Heman, the son of Joel, and, of his brothers, Asaph, the son of Berechiah; and of the sons of Merari their brothers, Ethan, the son of Kushaiah, were put in position by the Levites; And with them their brothers of the second order, Zechariah, Bani and Jaaziel and Shemiramoth and Jehiel and Unni, Eliab and Benaiah and Maaseiah and Mattithiah and Eliphelehu and Mikneiah, and Obed-edom and Jeiel, the door-keepers. read more.
So those who made melody, Heman, Asaph, and Ethan, were put in position, with brass instruments, sounding loudly; And Zechariah and Aziel and Shemiramoth and Jehiel, Unni and Eliab and Maaseiah and Benaiah, with corded instruments put to Alamoth. And Mattithiah and Eliphelehu and Mikneiah and Obed-edom and Jeiel and Azaziah, with corded instruments on the octave, to give the first note of the song. And Chenaniah, chief of the Levites, was master of the music: he gave directions about the song, because he was expert. And Berechiah and Elkanah were door-keepers for the ark. And Shebaniah and Joshaphat and Nethanel and Amasai and Zechariah and Benaiah and Eliezer, the priests, made music on the horns before the ark of God; and Obed-edom and Jehiah were door-keepers for the ark.

And he put some of the Levites before the ark of the Lord as servants, to keep the acts of the Lord in memory, and to give worship and praise to the Lord, the God of Israel: Asaph the chief, and second to him Zechariah, Uzziel and Shemiramoth and Jehiel and Mattithiah and Eliab and Benaiah and Obed-edom and Jeiel, with corded instruments of music; and Asaph, with brass instruments sounding loudly; And Benaiah and Jahaziel the priests, blowing horns all the time before the ark of the agreement of God.

So he made Asaph and his brothers keep their places there before the ark of the agreement of the Lord, to do whatever had to be done before the ark at all times day by day: And Obed-edom, the son of Jeduthun, and Hosah, with their brothers, sixty-eight of them, to be door-keepers: And Zadok the priest, with his brothers the priests, before the House of the Lord in the high place at Gibeon; read more.
To give burned offerings to the Lord on the altar of burned offerings morning and evening, every day, as it is ordered in the law of the Lord which he gave to Israel; And with them Heman and Jeduthun, and the rest who were marked out by name to give praise to the Lord, for his mercy is unchanging for ever; And Heman and Jeduthun had horns and brass instruments sounding loudly, and instruments of music for the songs of God; and the sons of Jeduthun were to be at the door. And all the people went away, every man to his house; and David went back to give a blessing to his family.