I did a quick math and designed an Helmholtz Resonator using the formula to tune at 50Hz. I am not sure of the implementation though as this will require to channel the low frequency to the mouth of the pipe for it to resonate at 50Hz. I can imagine channeling of the air, but again this could hamper with the mid-range too. I think a TL-sub will be a better option for the low end as i will be venturing into an unknown territory with limited budgets.Hari, if you are willing to take a chance and experiment, this design may well click with your driver:
http://www.decware.com/newsite/ZOB.html
Its single driver design, very interesting with kind of indirect BLH. You may compare the specs of the driver used with your own driver TSP after it arrives.