Contradiction with 1 Chronicles 15:19
It contradicts by listing additional musicians not mentioned in 1 Chronicles 15:18.
1 Chronicles 15:19: So the singers, Heman, Asaph, and Ethan, [were appointed] to sound with cymbals of brass;
Contradiction with 1 Chronicles 6:31
It contradicts by naming those appointed over the music versus the doorkeepers mentioned in 1 Chronicles 15:18.
1 Chronicles 6:31: And these [are they] whom David set over the service of song in the house of the LORD, after that the ark had rest.
Contradiction with 1 Chronicles 16:4-5
It contradicts by listing a different configuration of Levites and their roles compared to those mentioned in 1 Chronicles 15:18.
1 Chronicles 16:4-5: And he appointed [certain] of the Levites to minister before the ark of the LORD, and to record, and to thank and praise the LORD God of Israel:
Contradiction with 1 Chronicles 23:5
It mentions a larger number of musicians than those indicated in 1 Chronicles 15:18.
1 Chronicles 23:5: Moreover four thousand [were] porters; and four thousand praised the LORD with the instruments which I made, [said David], to praise [therewith].
Contradiction with 2 Chronicles 5:12
This verse lists additional Levitical musicians and mentions instruments not referenced in 1 Chronicles 15:18.
2 Chronicles 5:12: Also the Levites [which were] the singers, all of them of Asaph, of Heman, of Jeduthun, with their sons and their brethren, [being] arrayed in white linen, having cymbals and psalteries and harps, stood at the east end of the altar, and with them an hundred and twenty priests sounding with trumpets:)