best matching full range speakers for sx880 pioneer (60W rms per channel)

Pioneers with 4" Woofer wont able to goes more that 55hz down , cant reproduce big rock drums and tuba sound Thanks

Infinity Interlude IL40, -6dB @ 35Hz, hard to beat at a used price of under $300
 http://timg.danawa.com/prod_img/large/group_33/16964_2.jpg

Polk makes a $300 speaker with a 6-1/2" mica-reinforced poly driver
ELAC has one with a 6-1/2" aramid-fiber driver
- either should be pretty stiff

also, see what JBL, Epos & Cambridge Audio have

you can do pretty well these days for low bucks, but you will give up SQ in the mid-range to get the low freq.s

or call up Andrew Jones and tell him you've got another challenge for him...

For $300 some used Cerwin Vegas. That would do the trick if you want full range sound. They won't be the most refined things around but they sound pretty good, fun, and probably the closest to full range you are going to get in the $300 range. 

The large Advent would be a nice fit. Plenty on Ebay within your budget!