Is high current in a speaker the same as high voltage?
For a given voltage, the impedance of the speaker determines the current.

For a given current, the impedance of the speaker determines the voltage.

In order to get a given current with a given voltage, you need just the right impedance.  So you can't drive 100A at 1V into an arbitrary speaker -- you would have to find a \$\frac{1}{100}\$-ohm speaker (and some really thick speaker cable).

So for a single 8-ohm speaker, the power you can drive into it depends on the voltage -- if you want more power, you need more voltage.  This is why car speakers are often 4-ohms -- it's an easy way to get twice the power that you could with 8-ohm speakers, from the 12V that's available in the car.