I'm trying to get a good understanding of why many reviewers think Rythmik subs sound better, cleaner, or better with music than other competitors. One such competitor is SVS. I am just comparing two subs that are very close in performance and price. Like the SVS PC 13 Ultra and the Rythmik FV15 HP. Both subs were extensively measured on data-bass by Josh Ricci. (Technically Josh measured the PB 13 Ultra, but according to SVS the performance of the PC 13 Ultra is basically identical.)

In most regards their performance is very similar. They both have multiple tuning options. They both have very similar long term output compression curves, keeping flat frequency response as the output level is increased until the sub reaches the limit and eventually it just stops playing louder (in the case of SVS) or it stops putting out the lower frequencies (in the case of Rythmik). The transient response of both subs are very close to one another looking at the waterfall and group delay plots. But then we come to distortion. Both subs don't seem to have any higher order harmonic components of distortion, when the subs are pushed hard. It is only 2nd, 3rd and 4th order harmonics present in the plots. But, the SVS sub has very low distortion. Even when pushed to about 118 dB output level (at 50 Hz) it still manages to keep less than 10% THD from about 22 Hz and up. However the Rythmik sub on the 115 dB sweep from 35 Hz and below has quite large THD in comparison. The only slight weakness that I can see of the SVS sub is that the 3rd order harmonic is the largest component of the distortion rather than the more pleasant sounding 2nd order harmonic. However, this doesn't seem like it would matter since the SVS sub has such low THD to begin with, even when pushed hard and then it just stops playing louder rather than letting THD get larger than about 10%.

I'm not trolling trying to pick a fight. I just want to understand what I am missing. One of the reasons I gave my Sierra 2s an audition in the first place was because the measurements seem to indicate that it truly is an exceptional speaker. After listening to them compared to a couple other close competitors, they did in fact sound more realistic and lifelike in many ways. However, with subwoofers of this size there are more substantial costs involved with demoing them in my own room. I'm hoping that I just purchase a pair of subwoofers and be done with it.

So why are Rythmik subs praised so much for their sound quality, in comparison to most of the other competitors, like SVS for example? Is there more than all of the aforementioned quantities that drastically influence the "sound" of a subwoofer? Is it that some things just can't be measured?