Question

My timpani play a rhythmic song,
With hammer on anvil I play along.
Down my canal no ship sets course,
And I have a stirrup that fits no horse.
What am I?

Answer 1

A human ear

Timpani are a set of drums (kettledrums).
A hammer is a hammer-shaped bone in your ear, it is also called a malleus.
An anvil is an anvil shaped bone in your ear, it is also called an incus.
The "canal" is your ear canal, through which sound enters you ear.
A stirrup is a bone in your ear that is shaped like a stirrup, it is also called stapes.