Freaking Phase!!!

[nicolaad30]

hi, I still am trying to understand what phase relationship means.

I've read a lot of articles about it but can't get to conceive what they say. I already know that it is very important and that it changes dramatically the way music sounds.

If you can help me with this I'll apreciate it

Thanks
nicolaad

 

[AlChuck]

It really will only make sense to you if you have a basic understanding of waves. It's simple stuff. I'll give it a shot.

One fundamental fact is that sound waves exist as disturbances in the air. The disturbance scrunches the adjacent air molecules together, and this compression propagates through the air not too unlike the way water waves move.

Say you have two identical waves in the air. Each disturbance will affect the air in an additive way -- the pressures caused by each wave source are additive. If the two identical waves start at precisely the same instant and location, the resulting sound will be louder. But if the one wave starts one half of a wavelength before or after the other (either by being delayed relative to the other or by being started in a physically different spot), the two waves will exactly cancel each other -- there will be no disturbance, hence no sound.

Think of a single molecule of air moving in response to the push it's getting from the source. If the pushes are completely in phase, there are two pushes in the same direction on the molecule, so it moves twice as far. If the pushes are completely out of phase, there's a push in one direction and an equal push in the opposite direction; so it doesn't move at all.