it all about current flow out in a piece of wire , having resistance
Let suppose
you are person ( current) which you are going to pass a really narrow street , on that street there are crowd of 4 people , there street is too narrow .. u will find difficulty to pass by them "saying excuse me etc )" there 4 people are 4 ohms
the next day u again pass by the same narrow street , that day u see , a crowd of 8 people , now as i told u the street is too narrow , it will be very hard to you to pass by them
8 people`s ( 8 ohms)
then another day it happens but there is only 2 people , u will find much easier to pass by them , (2 ohms)
then another day , same thing happens , now there is only 1 person , u will find the most easiest to pass by him ,
(1 ohms)
so ohms is the crowd , and current is you , the more crowd , the more harder to pass
similarly
the more resistance the more harder to current flow
the less resistance the more easier to let the current flow
in 8 ohms case , voltage help current to flow
if u couldnt pass 8 person crowd , u will need some one to push u at the back to penetrate them
similarly
as current flow is slower in 8 ohms , voltage ( the potential difference) raise up to let the current flow
but this causes heat in a circuit
so better u have less ohms
it doesnt means that u go for 1 ohms ,
it can burn ur amplifier if ur amplifier support 1 ohms load ,
because the less ohms , the easier flow of current ,
for the optimum resistance go for d2 and put in on 4 ohms
4 ohms is the ideal resistance of sound driver , speaker , woofer and tweeter