In the story the narrator is reading, the dragon shrieks when Ethelred kills him. What does the narrator hear in the house?

From the text:

Here again I paused abruptly, and now with a feeling of wild amazement — for there could be no doubt whatever that, in this instance, I did actually hear (although from what direction it proceeded I found it impossible to say) a low and apparently distant, but harsh, protracted, and most unusual screaming or grating sound — the exact counterpart of what my fancy had already conjured up as the sound of the dragon’s unnatural shriek as described by the romancer.