This is a thread, or is it?

[blackmage_nuke]

I answered that question with my post. =]

If you move your arm fast enough past your ear, you'll hear a sound. So it's right in that stretching your arm into the air would cause (not "be", if we're being pedantic) a sound, just a very small one that most people wouldn't hear. In fact, some sounds aren't heard by people at all. But yes, a sound all the same. That's why there are dog whistles. We can't hear them, but the vibrations exist, and it turns out dogs can hear them. It would be silly to dismiss something as soundless just because we don't hear it.

But by the logic of "it's a vibration, then it's a sound" the movement of any matter even the arm itself would be considered sound. After all the "sound" of the tree falling is vibration of air. Sound can travel through solids as very tiny vibrations, moving my arm is simply making the vibration very big and very slow and therefore by Kentarou's original logic of "if it falls in the forest it still makes a vibration therefore it still makes sound" since moving my arm is a vibration it is "sound". Thats why the only way to define sound is if it is heard.

Also if you record it then the recorder is recording the vibrations not the sound, and when you play it back then the recorder is making the sound, not the tree