Help with speakon connections

How do I wire one jack (jack 1) for input to the speaker and the other (jack 2) as a jumper to connect an additional speaker in series?

Is it as simple as just 

wiring jack 1 normally to the existing positive and negative of the cabinet, 

Then connecting the +(pos) of jack 2 

to the -(neg) from jack 1,

And the -(neg) of jack 2 

to the cabinets negative?

Or am I missing something?

No, unless you made a mistake it is always +1 to +1, -1 to -1, and the cleanest and easiest way I have found to do that is to create a Y cable so there is only 1 wire to physically connect to each speakon terminal.