Just wave!

Just need substantiation on a speaker building point:

With a TL speaker, one of the main reasons for the transmission line is to reverse the polarity of the wave, off the back of the speaker, so that it will be in phase with the front of the speaker cone, when it exits the port.  Knowing the resonant frequency of the speaker and its wavelength, we them determine the length of TL which will allow the inverse of the back wave to be 'happening',...when it leaves the port?  To put it another way:  we are bouncing the wave within the TL until we are, essentially, releasing it....while it is in the proper orientation.  Is that correct?