What do you mean by midrange smear? Not sure I follow what you are trying to describe.

If you design the enclosure geometry and distribute the stuffing correctly, then I don't think you will have spikes in the midrange response. You may end up with a +/- 2 dB ripple but this is small compared to all of the other artifacts from the room and front baffle on the SPL response.

Probably the safest and smallest classic TL design is a tapered pipe. This enclosure will push the 3/4, 5/4, 7/4 ... standing waves higher in frequency where they should not be a problem.

Martin