the eon's range is 38Hz-20kHz while the jrx115 is 38Hz-16kHz so the eon can cover more frequency...
however, both JBL have 1" high frequency driver while the yamaha uses a 2" high frequency driver. if it sounded quite better for you then I'm going to guess that you listened to something that uses more mid-range to high when you heard it. if you are not into hip hop or rap that needs the low end then you should be fine with the yamaha. the extra inch on the yamaha HF driver really does help with bringing out details on the mid-range to high frequency which is what we listen to anyway for the most part.