With a transmission line you will get a wavy response because at some frequencies the wave at the port is in phase with the direct wave from the woofer, reinforcing and causing a peak. At other frequencies the port wave is out of phase, causing a dip.

With a transmission line the line can be stuffed with wool or other absorbing material, forming a low pass filter, and killing off the wavies at higher freqencies... leaving only the reinforcing waves in the DESIRED passband down in the bass region where it is needed.

The same can be done with a "scoop" enclosure.