Possible Clues:

• Haydn genre
• What the Juilliard String Quartet plays
• Church gives warning to stop tune that's orchestrated for small audience
• Pot and reggae, for example, is orchestrated by a small ensemble
• It needs a small orchestra
• Compositions to be played in a room?
• Some of Haydn's work
• What might be instrumental in a legislative assembly?
• Works for a small group of instrumentalists
• Such entertainment provided by parliamentary notes!