basically a t-line will have less frequency roll off under and above tuning. basically it plays a broader frequency range. With the t-line if you tune low or high you dont necessarily lose the lows or highs. this box is tuned to 34hz. which usually with a regular ported box tuned that low and you would start to lose alot of upper bass response but with the t-line you dont. Same as if it were tuned high. A t-line is a very good box you just have to know how to build them and know how to make the compression chamber right in order to keep the subs suspension under control. With this box giving that sub roughly 17-1800rms i had no need to run a SSF as it has a small compression chamber. Hope this helps a little in understanding the box. In short its just an all around great box, get loud, get low as crap, has a nice sound too it and plays withing a big range, lows highs whatever it may be.