How many people can play Rock Band 4 at once?

Up to six people can play Rock Band 4 - one drummer, one bassist, one guitarist, and up to three vocalists with the inclusion of vocal harmonies. You can only play Rock Band 4 with the appropriate hardware synced to your console for the game to host up to six people! Please keep in mind that Rock Band 4 will support up to 4 profiles at a time regardless of how many players are playing at the same time.