One can never make a definitive statement, but if you are building a two way dipole system then chances are that the bass is going to be acoustically (note I am not talking about the textbook electrical filter parameters for a pure resistor) rolled off in the 200 Hz range. Now the next driver up in the frequency range will need to have a complimenting ~200 Hz high pass acoustic filter. This usually means an electrical high pass filter in the 400 to 500 Hz range for baffles like the one shown in Poultrygeist's pictures. The only way I see of avoiding the high pass filter is if your driver has a naturally rolling off behavior at 500 Hz which seems unlikely. I have tried the unfiltered approach with a few different driver combinations and found it did not sound right compared to a correctly designed high pass filter. If you run the appropriate simulation is shows the problem very clearly.
