New Revised Standard Version
Now these are the singers, the heads of ancestral houses of the Levites, living in the chambers of the temple free from other service, for they were on duty day and night.

Contemporary English Version
The Levite family leaders who were the musicians also lived at the temple. They had no other responsibilities, because they were on duty day and night.

New American Bible
These were the singers and the gatekeepers, family heads over the Levites. They stayed in the chambers when free of duty, for day and night they had to be ready for service.

Douay-Rheims Bible
These are the chief of the singing men of the families of the Levites, who dwelt in the chambers, by the temple, that they might serve continually day and night in their ministry.

These are the chief of the singing men of the families of the Levites, who dwelt in the chambers, by the temple, that they might serve continually day and night in their ministry.

the singers

1 Chronicles 6:31-33 These are they, whom David set over the singing men of the house of the Lord, after that the ark was placed. . . .

1 Chronicles 15:16-22 And David spoke to the chiefs of the Levites, to appoint some of their brethren to be singers with musical instruments, to wit, on psalteries, and harps, and cymbals, that the joyful noise might resound on high. . . .

1 Chronicles 16:4-6 And he appointed Levites to minister before the ark of the Lord, and to remember his works, and to glorify, and praise the Lord God of Israel. . . .

1 Chronicles 25:1 Moreover David and the chief officers of the army separated for the ministry the sons of Asaph, and of Heman, and of Idithun: to prophesy with harps, and with psalteries, and with cymbals according to their number serving in their appointed office.

Ezra 7:24 We give you also to understand concerning all the priests, and the Levites, and the singers, and the porters, and the Nathinites, and ministers of the house of this God, that you have no authority to impose toll or tribute, or custom upon them.

were free

Nehemiah 11:17,22,23 And Mathania the son of Micha, the son of Zebedei, the son of Asaph, was the principal man to praise, and to give glory in prayer, and Becbecia, the second, one of his brethren, and Abda the son of Samua, the son of Galal, the son of Idithun. . . .

they, etc.

Psalm 134:1,2 A gradual canticle. Behold now bless ye the Lord, all ye servants of the Lord: Who stand in the house of the Lord, in the courts of the house of our God. . . .

Psalm 135:1-3 Alleluia. Praise ye the name of the Lord: O you his servants, praise the Lord: . . .