To add even more that is just with an amp with a regulated power supply if it's unregulated then you will increase power. If your going for spl, otherwise not really worth the effort and as mentioned a higher than normal voltage causes other problems.

 

meant in general terms..you can`t have one without the other.

 

No. Your initial post was just wrong. Adding "in general" doesnt make sense or make it right. ha

And this post is also wrong, you can indeed have voltage without current. But not the other way around.