The Dayton DS215 uses the same cone and surround as the SD215A-88 subwoofer and it suffers from the same kind of dip just above 1kHz.  It's a bit larger on this one and didn't show as strongly until I measured the design outdoors where I could get a longer gate time for higher resolution.  Luckily the dip is mostly benign and does not impart any irritating qualities to the sound.

Bass extension is not quite as deep as the SD215, with the tuning I used at the port full length (~35Hz) F3 is roughly 50hz with an F6 in the low 40's (4pi).  Since it's an 8 ohm design efficiency is higher then the SD215 but sensitivity is still just a hair lower at ~84.5dB - 1W/1M (2.83v/1M). 

Distortion from this woofer in low midrange and bass is much lower compared to the other 8" woofer variants I've tested even though the design does not implement any additional distortion reducing measures in the motor itself.  I suspect it's largely due to the larger motor/magnet system which minimizes flux modulation but I can't be entirely certain. I believe it might share the same spider as the SD215 so the motor system would be one of the only differences between that woofer and this one.  It does have a spike in 3rd harmonic distortion around 1kHz which is made more prominent on the normalized distortion graph due to the dip in the fundamental near the same range.  Though it's fortunate the relative level of that 3rd harmonic distortion spike stays roughly the same as output level is increased which keeps it from being an annoyance at higher levels.

Bass and midrange sound quality is actually quite nice, I think in part due to the lower distortion and low compression from this woofer.  The bass has a quicker, snappier and cleaner feel to it that does not mask the low midrange.  Vocals sound very good, clean with good detail and not too recessed nor to forward even with the ugly looking dip in the frequency response.      

The high frequency performance/sound quality is largely the same in all the designs so this section will likely be a cut/paste for each.  The LaVoce DF10.101LS with the Celestion H1SC-8050 is a very nice combo, the smooth easy to work with  frequency response  results a very clean clear uncolored high frequencies with remarkably low distortion and compression.  The high frequency driver has to work very little in this design so its composure is maintained well beyond the point where the 8" woofers are begging for mercy.  The only negatives are the slightly narrower coverage of the horn then I would have liked and the early drop in high frequency output past 16kHz.  For the cost I don't mind as they are not glaring issues that you notice immediately and the narrow dispersion could actually be a benefit depending on the desired use of the speakers if wanting a more focused dispersion pattern to keep excessive energy off the walls.