Actually one of the biggest advantages to strapping most amps is the fact that you DONT have to synchronize them with one another... the master/slave function does it for you.

When you strap amps, you connect the negative speaker outputs from one amp to the negatives on the other. The positive coil(s) on the sub is connected to the positive speaker output on the master amp, and the negative coil(s) on the sub is connected to the positive speaker output on the slave amp.