You need to correct your query where clause should be used after your join statements and also you are not using proper table names, according to structure shown in question you can write your query as
SELECT * FROM albums a
INNER JOIN people p ON a.idauthor = p.id
INNER JOIN people p1 ON a.idcompositor = p1.id
INNER JOIN people p2 ON a.idfeat = p2.id
where a.idalbum=:id