400 MH and 400 HPS at the same time?

[smoknjoe]

I think you're refering to the "double slit experiment".

Yea, I am. The double split experiment proved that the light waves were interfering.

Two EM waves (electromagnetic) can't be added together to create a greater amplitude.

By the same token, they don't "interfere" with each other, and create "interference patterns".

Type "electromagnetic waves interference" into google.