There's two basic ways to do the ordering, using a client side query mechanism with a case statement, or with a secondary table.
I'd use the secondary table, like so:
order_table:
id | cat
1 | saxophones
2 | trombones
3 | tubas
4 | trumpets
and so on, then just do:
select * from yourtable yt left order_table ot on (yt.section=ot.cat) (more query goes here) order by ot.id