Will phase difference have any effect on an audio signal?

helo,

For example, if you amplify an audio signal with an inverting op-amp what would the difference be between the original signal and the amplified signal. Will the audio be played upside down?

Thanks

Technically yes. Is your output mono, or stereo/multichannel?

Just say a person is talking into a microphone which is amplified using a negative feedback inverting op-amp. And the same person was talking into a microphone which is amplified using a negative feedback non-inverting op-amp. I want to know what the difference would be to anyone who is hearing it?

Probably nothing at all. Generally, absolute phase is not important. In multiple speaker/channel systems, relative phase can matter, due to cancellation effects. Many amplifiers invert phase, pretty much nobody notices.

A good many audiophiles would disagree with you especially if only one channel was inverted, but as this is Arduino and its incapable doing much with hi-fidelity audio signals..........

Yes, which is why I mentioned relative phase in multichannel systems. You don't need to be an audiophile to hear that problem. Some audiophiles claim to be able to hear system-wide absolute phase inversion, but I've never been able to tell.