Your L100t's go down to about 40Hz at -3db as I recall. I've got the t3's and for sure these speakers will deliver most if not all there is of deep bass from LPs. But, here's the rub, Dance Music on CD and Movies have bass or sound effects which dig deeper than where the JBL L100's in any flavor can reach. It's why I supplemented my pair with a 15" JBL B380 Passive Sub, which I powered with a Sony TA-N80ES, operating in bridged mode to deliver 560 watts at 8 ohms. Now, this sub gets into the 24 Hz arena at -6db and has paid off on Dance Music, Jazz with Double Bass, and, of course, movie sound effects, greatly enhancing my overall listening/viewing pleasure. I have the mains set to crossover at 60Hz which is what JBL recommended. And, thus, with the sub set for 60Hz, the bass is seamless to higher frequencies and there are is no pumping effect. The bottom line is a sub will indeed get you lower bass than your L100t's will deliver but you'll get nothing from it if mains are set to deliver full frequency and frequency only gets down into the 50Hz arena.
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