MacBook Air 13" Mid 2011 Battery
MacBook Core 2 Duo Battery
The speaker is connected to the I/O board and is shown in the very last picture. Zoom in to find it. There's a two pin connector that connects it to the board and it looks like two screws to secure it. iFixit took the picture of the I/O board with the speaker already removed, but then included it in the final image.
Removing the logic board seems to be unnecessary. I was able to replace the dock connector by simply removing the speakers and battery.
Also, it'd be nice if the dock connector came with a new moisture sensor.