John Gill Commentary 2 Chronicles 29:28

"And all the assembly worshipped, and the singers sang, and the trumpeters sounded; all this [continued] until the burnt-offering was finished." — 2 Chronicles 29:28 (ASV)

And all the congregation worshipped
Bowed their heads as a token of divine adoration: and the singers sang ;
both with vocal and instrumental music, who were the Levites: and the trumpeters sounded ;
their silver trumpets; these were the priests: and all this continued until the burnt offering was finished ;
with all appertaining to it, the meat and drink offerings.