Don't confuse current and voltage. If one end is -10V and the other is
+10V, then a conductive path between them will have 0V at one point.
Voltage is relative, of course.



In article ,
Eddie Runner wrote:

No it doesnt Kevin.
If the voltage was ZERO half way in the speaker coil then
there would be no current, and kurcheff tells us this is not
possible! In a circuit the current is the same everywhere!

Eddie Runner

Kevin McMurtrie wrote:

Yes, bridging cuts the perceived output impedance in half. Think of it
this way. The two outputs are exactly opposite. Halfway inside the
coil they cancel to zero volts. It's like each amp is seeing a coil
half as long.


Cancels to zero volts
here in center
v
2 Ohms v 2 Ohms

^^^^^^^^^^^^^^^^^^^^
| |
| -- 4 Ohms -- |
| |
+ phase - phase