In the typical listening room, there is usually what's called a room "peak" or "suck-out" around 25Hz. I forget what this is due to, but it is so common that a lot of speaker manufacturers (particularly subwoofer w/ built-in amps like the Martin Logan Depth and Descent) come with a contouring control that lets you boost or cut the energy at this frequency.
In your old room, you were probably getting bass reinforcement in this region which "lifted" the natural roll-off of your speakers. So, lucky for you, you didn't need a subwoofer. But if you want to recapture that last bit of low end in you new room, you probably should consider one.