While i read the novel 'rain', one sentence looks awkward to me. the sentence is below

'in his ears hammered still the harsh notes of the mechanical piano'

I think it means that he heard the harsh notes of the mechanical piano But i don't understand how 'ears' can hammer the harsh note. What is subject and verb in this sentence?

I really appreciate if you answer my question

ps- sorry for my poor english

While I read the novel 'Rain', one sentence looks awkward to me. the sentence is below

in his ears hammered still the harsh notes of the mechanical piano

I think it means that he heard the harsh notes of the mechanical piano but I don't understand how 'ears' can hammer the harsh notes. What is subject and verb in this sentence?