So after reading this article or guide
https://www.avsforum.com/forum/113-subwoofers-bass-transducers/2958528-guide-subwoofer-calibration-bass-preferences.html#VIIIA
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All of the measurements of frequency response, which we are comparing, were performed quasi-anechoically. That means that the measurements were taken outdoors, away from any other objects or structures, with the subwoofers sitting on the ground. Starting with the PB13, with the Sledge amp in extended mode, we can see that the subwoofer's native frequency response starts to roll-off slightly at about 30Hz. By 20Hz, the native response is down about 2db (about a 40% difference in perceived loudness at that frequency) and it then recovers a decibel (bumps up slightly) out to about 16Hz. Below 16Hz, which is really about the port tune, it rolls-off more rapidly.
Looking at the V3611, we can see that the subwoofer starts a slight roll-off at 40Hz. By ~30Hz, the response is down by ~1db, and by 20Hz, the response is down by about 3db (about a 60% difference in perceived loudness at that frequency). Below 20Hz, the subwoofer has a steady roll-off. By about 16Hz, the subwoofer is down 7 or 8db (well over a 100% difference in perceived loudness) compared to its native output at 40Hz and higher.
That is an enormous difference, compared to the PB13, and I think that the difference could be audible in most rooms, to many listeners, with the PB13 sounding relatively (slightly) heavier in the low-bass, and the V3611 sounding relatively more impactful in the mid-bass, at virtually any listening levels. The reason that I think that the difference in low-bass heaviness might be slight compared to the difference in mid-bass impact is just that there is more mid-bass content, and we might be more likely to notice differences there.
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Looks like the HSU dropped by 11.7 db from 40hz to 20hz where as the pb12 Ultra dropped only by 7.3db
My SB-13 Ultra dropped by 10.8. If I understood this correctly then the PB12 will have heavier bass then the HSU
The HSU will have 2 to 3 more db around 40hz and above. Of course my SB-13 Ultra will catch up aournd 63hz
