Difference between a ML TQWT (expanding) and a Tapered TL (contracting)

[mhd204]

Why use a mass loaded expanding taper TL, when a contracting tapered TL does the same thing?

Plus, the contracting tapered qwt is not as long and easier to build.

It seems that adding a port to the end of an expanding tapered TL reverses the potential benefit of higher efficiency. All it does is make it respond like a contracting tapered TL. Am I missing something here?

[GM]

Well, when you present it this way, it doesn't seem to be worth the extra cost/effort, but all box alignments 'color' the sound to a greater or lesser extent and to my ears (or at least back when I had youthful hearing) a ML-horn (expanding) is best suited for effectively higher Qt systems while TQWT (contracting) are better for lower Qt, with TLs (constant taper) overlapping these across the medium effective Qt range.

If a traditional high stuffing density is used though, I imagine they all average out in the pipe's pass-band (< ~ Fs*Qts/2) with only how it affects the driver's mids/HF being the only way to potentially tell the difference.

GM