Why does the SVS Prime Pinnacle tower speaker feature three ports on the rear panel of the cabinet?

[Older_not_wiser]

New owner of Prime Pinnacles. Bought through Crutchfield because of sweet return policy and quick shipping. I was not excited initially after setting these up with a new Denton AVR. However, I changed my music source to CD-quality and Master (through Tidal) and they were PERFECT. Maybe, just maybe the treble seems a bit harsh on some female tracks but not much. I’m an electronics engineer, I’ve built speakers and amps over (a long) time. My primary speakers are 8’ tall columns with an equalizer but in this location I was forbidden from doing that again. The PP’s aren’t as good as my fully DSP-equalized columns with SVS Subwoofer but they are close. And the PP are PLENTY good for the price point. I’m in a big room, maybe 40’x30’, PP angled to the listening position, and AVR set flat. It was easy to hear compression problems with my initial music source and I was hoping it wasn’t the speakers. It wasn’t; good source = good sound. Buy these if this is your price point.

[rushgush]

would like to see an update on the ultra line of speakers and subs. or maybe a speaker above the ultra line. oh pc3000 sub would be nice 😁