The matter of “separate libraries” has puzzled historians for quite a while, because it was wondered whether this meant the two bands also played different pieces. The question was asked that if the bands both played different titles then how would all eight have been able to perform together as the ship was sinking? My theory is that both bands would have played from the same list of titles, even with separate libraries.
The Matter of Requests
First and Second Class passengers received the "White Star Line MUSIC" songbook upon embarkation, which listed the music that could be played upon request. In First Class the quintet played in two venues: at the top of the famous grand staircase and in the Reception Room outside the First Class Dining Saloon. The trio played in the First Class Reception Room adjoining the à la carte Restaurant and Cafe Parisien.
It would have been terribly confusing to the First Class passengers if they were able to make requests of the quintet but not the trio. Passengers waiting for a table at the restaurant would have enjoyed the same privilege of asking for favorites of the trio as in the other parts of the ship when they listened to the quintet. Passengers would have used the same booklet for the entire voyage.
Back to the question of separate libraries: beyond the musical considerations mentioned in the last post, or the matter of requests, imagine how inconvenient it would have been to share the same "library." As the ensembles often performed simultaneously, both needed immediate access to the music on the request list.
So, yes, the quintet and trio had separate libraries, but no, would not have had different playlists. Both would have been required and able to play music from the "White Star Line MUSIC" songbook upon request.
Did Titanic's band play music by memory?
Did Titanic's bands share sheet music?
What was listed in the White Star Line MUSIC songbook? Part I