I hope such a simple question is acceptable here, but hopefully the knowledgeable ones will help me understand.

With a speaker at 8 ohm, 99dB, and a speaker at 4 ohm, 96dB, will the volume be equal with the same amount of power (voltage) to each?

Why is the 8 ohm speaker so perfect for the Decware amps?

And is this chart:

http://www.decware.com/newsite/buyingguide.htmlfor 8 ohm speakers?

Wouldn't the chart be different for 4 ohm speakers?

I'm still not really understanding about this difference, and so far my research hasn't really clearly explained simply enough for me to understand.

Any help is appreciated.