Frequency Range - Bookshelf Speakers


For a 2-channel stereo system, which consists of a pair of bookshelf speakers and a powered subwoofer, what difference does it make if the bookshelf speakers go down to 70Hz vs. 30Hz (or anything else in between)?
agiaccio
I've tried, TRIED, I tell you! ... to properly integrate a sub with bookshelf speakers. In my experience (for what that's worth... not much), you don't want a monitor going lower than around 60hz or you start messing with serious room modes, etc. around the speaker/sub crossover and it's near impossible to get a good result.

The best scenario I've found is to get some good monitors that go reasonably deep and forget the sub; unless you're a fan of pipe-organ music, of course. Deep isn't the only criteria - they must go deep enough (~45hz) and be articulate in that region.

The Usher X-718's (-3db @ 42hz) I currently run fit this bill exactly and I don't miss the sub at all with rock nor jazz.
Post removed 
Bob is right, again. I personally like subs. You can put the bass anywhere you want for the best integration and let the monitors handle the rest. It will depend on the monitor's drivers and crossover as to the quality of the midrange. Better that way than to try to make a monitor play frequencies below 60 Hz. The sub may be localizable if it plays much above 80 Hz or is too loud. I prefer a monitor that is allowed to play full range and a sub that you can change the crossover, and phase. Its your best chance to integrate it without it being noticed.
Vinyladdict said "If I'm sending everything below 60 or 80hz to ONE sub (essentially mono'ing below 60 or 80hz... probably 80) should I have no problems with "woofer pumping" and subsonics?"

Did eliminating the subwoofer affect/help this problem? Do you still have rumble or subsonics without the sub? Could this be another reason not to use a sub? To eliminate modal response problems and inherent vinyl "noise" (subsonics and rumble).

Bob