The lower set of speaker terminals is for the woofers. The upper set is for the mid-range and tweeters.
Is this what your speakers look like?
http://www.infinity-classics.de/models/Reference-series-1+b-2-10+A+B-1981-86/Reference-Standard-2.5/RS2.5-11.jpg
http://www.infinity-classics.de/models/Reference-series-1+b-2-10+A+B-1981-86/Reference-Standard-2.5/RS2.5-3.jpg
If you hear rear EMITS, and front EMIMs and Woofers, the terminals must be jumpered together.
Is this what your speakers look like?
http://www.infinity-classics.de/models/Reference-series-1+b-2-10+A+B-1981-86/Reference-Standard-2.5/RS2.5-11.jpg
http://www.infinity-classics.de/models/Reference-series-1+b-2-10+A+B-1981-86/Reference-Standard-2.5/RS2.5-3.jpg
If you hear rear EMITS, and front EMIMs and Woofers, the terminals must be jumpered together.