1200 rear speaker connection

[crowesnest3]

last fall picked a a set of Marine Grade coaxils, small rectangular boxes that fit beautifully in place of the leather" stuff " pouches under the passenger armrests on my 84 Interstate. Bike did not come with rear speakers. When I wired them in I went a simple route ( maybe too simple?) I spliced into front speakers ( new OEM replacements). It works pretty well but definitely the rears seem to be running at less volume than the fronts, this is even just standing still and off of the bike. Would it be better or maybe even correct to access the amp and wire rears directly to that? .... or? Will be opening up the front before very long to replace the instrument cluster ( speedo took a crap ) have the replacement waiting. Even tho I have started to get very attached to my ear pods/ Iphone/ pandora would like the option of wind in my ears along with Howlin Wolf thru the speakers! .... Crowe ....