Dual plane vs. Single plane

[RJ & CJ]

Thre wasn't a general engines section, so I figured the most popular engine section would suffice. This may belong in another section, seeing as how this is just a curiosity thing, so please move it if it does.

I got this from an old thread.

Originally posted by 390 bracket
Correct me if I'm wrong: Along with a weight savings-(cast iron vs. aluminum)-aftermarket intakes generally will have better flow characteristics than oem jobs. You can get a single or dual plane intake. Single plane intakes are generally used for power farther up the rpm scale. Dual plane intakes generally work better at street usage rpm-showing better low rpm torque.They are much easier to drill for NoS WOOOOOPPAAAAAA

My question is, why are the single planes more suitable for higher RPM's than the dual planes are? I tend to function better when I know the functions of things, so I would appreciate a technical explanation as to how a single plane will change the breathing up top and provide for better performance. I'm just looking for the operational difference in single and dual plane manifolds.