no it usually is about 5 hz up from the port tune but that depends on the box size used ....people who do this usually aim for the resonant frequency of their vehicle
also scotts box probably wouldnt be useable anyway for anything other than a burp if he had a subsonic filter at his port tune because the box would be so unbalanced because of the intenional peak of the response curve for his resonant frequency
no i dont got a subsonic filter i guess ill make 2 boxes an this spl box@ 55hz will just b 4 the meter an the other box same size ill use 4 daily wit diffrent port tunes ill just use 1 4 in. pvc for a 36hz 30.8hz 32hz an 26hz myb more an in the spl box ill have 2 4in pvc pipe