Hearing music in the wrong key

1. Why do I hear songs in a different key?
2. What does it mean when you hear music that isn't there?
3. Why am I hearing music in a lower pitch?
4. What does it mean to be in the wrong key?

Why do I hear songs in a different key?

So the short story is that different keys are / were fundamentally different due to the application of ratios not preserving the exact frequency values of notes. This is apart from the the sound of higher/lower frequencies, which of course affect the aesthetics as well.

What does it mean when you hear music that isn't there?

A musical hallucination is a type of auditory hallucination where music is perceived without an external source. It is observed in primary psychotic illness, in sensory deprivation states like hearing impairment and organic psychosis.

Why am I hearing music in a lower pitch?

Diplacusis, also known as diplacusis binauralis, binauralis disharmonica or inter aural pitch difference (IPD) is a type of hearing disorder that is the perception of a single auditory stimulus as sounds of a different pitch in the two ears.

What does it mean to be in the wrong key?

TL;DR - It either means you're singing the wrong notes, or not accurately on the right pitch. 1.