What is negative amplitude + how to read parts of audio wav?

Hello,

Here is a newbie question about an audio wave in the arrange or edit window. In Logic Pro, I know you're able to adjust to view the amplitude scale as a percentage or in sample units. My question is what exactly are we hearing during parts of an audio signal that falls within the negative amplitude range of the scale? Is it simply a lower volume? Does zero on the scale = silence? If it does, then why are we able to hear audible signal during parts that occur below zero?

Also, how does relate to the scale in sample units? If viewing the amplitude in sample units, what does -6553 mean?

Thanks for any tips and feedback!

The waveform represents the electrical signal that will be reconstituted by your D/A converters, and routed to your speakers, where in turn it affects the displacement of the speaker membrane.

A speaker membrane (much like a microphone's diaphragme or an eardrum) has a resting position around which it can oscillate. When the waveform is on top of the zero line (the resting position of the speaker), then the membrane moves toward you. When the waveform falls below the zero line, the membrane moves away from you.

Hope that helps?

When the waveform is on top of the zero line (the resting position of the speaker), then the membrane moves toward you. When the waveform falls below the zero line, the membrane moves away from you.

That would be, as one look towards the front of the speaker I assume

Very helpful, thanks!

That would be, as one look towards the front of the speaker I assume

Yes, correct.