SOLVED. Three young adult books about a kid that has to play a certain song to become free/break a curse. [s]

[Krista]

Pretty sure there was a group of 3 siblings. At least one was female. They get separated at some point and something about an ice thing (king, monster,). I think one of them is named River. One of them had to play a song on an instrument and (maybe) one had to sing it.
I read it in 2008 ish possibly 2010.

[Emmy]

So, it doesn't sound exactly the same, but could it be Deltora Shadowlands? It's about a group of three travelers (two are children) that have to deal with a series of monsters in order to collect three pieces of a pipe and play a song with it. There's no one called River, but there is a character called Lief (leaf).

[Kate (Feathered Turtle Press Reviews)]

Some parts sound vaguely similar to The Naming and series.

[Gillian]

How about Drowned Ammet by Diana Wynn Jones. There are 4 siblings, but not all 4 are present the whole time. They take a boat down a river, and there's a scene where they reach the end of the river and fight an evil wizard - there's a lot of song magic, and weaving magic. It's one of a 4-part series called the Dalemark Quartet.

[Krista]

It is indeed “The Books of Pellinor” (the Naming, the Riddle, the Crow, and the Singing)

Thank you for the help.

[Sue]

Gillian; the book you're thinking of is The Spellcoats.