Originally Posted by Just Jeff
That's a good drawing by slowhike. Also, look at the picture on the JRB MWUQ4 page of them stretching the quilt out tight...and there's still no compression of the down. That's the advantage of a differential quilt...you can snug it up tight to the hammock and none of the down will be compressed. Warbonnet Yetis are also differentially cut. KAQs are differential synthetic versions.
A non-diff quilt is generally a flat quilt...it's two pieces of the same size of shell material sewn together. Like the Nest and no Sniveler.
Differential quilts usually have shaped baffles as well, whereas a flat quilt's baffles will generally be rectangles of mesh. The diff's baffles might be shaped like a flattened-out "U", with wider U's at the shoulders and narrower U's at the knees.
JJ, et al,
The real benefit is not the differential cut, though that is important, it is the body contouring radial baffles... The only UQs with radial or contoured baffles are the JRB Mt Washinton Series and the Speer Snugfits...All the other differentially cut UQ have staight baffles...If another has added curved baffles they may want add a comment, but I've not seen this detail preveously posted anywhere.
It is also fair to note that three season flat quilts are excptional performers as TQ and above 30* are also more than adequate as UQ... Thus for those seeking the multifunctionality of TQ or UQ they offer excellent capability often at lower cost and thus may be the value alternative.
The true value of Differential Design AND Shaped Baffles is in increased constancy of loft for temps below freezing and this value increases as the temperature drops... FWIW, this is the reason that the JRB Mt Washington 4, a true zero degree UQ, was introduced before the three season Mt Washington 3. This is also why the JRB Mt Washinton 3 and the Speer Snugfit both perform well at 20* for three season UQs, which is a good 10* below the previous 30* range of three season flat UQs.