Adam Clarke on 2 Samuel 6:12

So David - brought up the ark - The Vulgate adds to this verse: And David had seven choirs, and a calf for a sacrifice. The Septuagint make a greater addition: "And he had seven choirs carrying the ark, a sacrifice, a calf, and lambs. And David played on harmonious organs before the Lord; and David was clothed with a costly tunic; and David and all the house of Israel, brought the ark of the Lord with rejoicing, and the sound of a trumpet." Nothing of this is found in any MS., nor in the Chaldee, the Syriac, nor the Arabic, nor in the parallel place, 1Chr 15:25.