3-4 dB dip at crossover region: what should I listen for to hear it?

Not sure if this is right or relevant (better informed posters like Mr. Squires, please correct me if I'm wrong), but such "dips" (i.e., "3-4 dB at about 1.5 kHz") are not analogous to, say, missing a shade of blue between Cerulean and Cobalt. What I mean is that the missing shade of blue will jump out as a gap to the eye. The "missing" decibels "around" 1.5 kHz, however, are as it were blurred together with frequencies just below and just above. It's not a discreet gap. I learned this by using a crossover to send "only" frequencies below 50 Hz to my subwoofer. I found that if I shut off my main speakers, I still got sounds out of the sub that were clearly above 50 Hz. A knowledgeable friend described this slope phenomenon to explain why. If this is a poor explanation, I would appreciate gettin' schooled by someone better informed.

BTW, the SPL meter linked above (by elliot...) is only A-weighted. But C-weighting is much more relevant for music, as it doesn't discriminate against low frequencies. If you are listening to music loud (say, 90 dB or more C-weighted), and switch your meter to A-weighting, the level will drop significantly (to 80 dB or even less). 

One more thing. Several here have objected to measurements in principle, appealing to what your ears like as the only relevant standard. Well, yeah, of course. But that doesn't mean measurements are irrelevant. I don't want to open up this always contentious can of worms, but the fact is that measurements are used by the scientific engineers who design the equipment, and they do correspond, in "objective" ways, to our "subjective" ear-experiences. Duh. If you simply reject the relevance of measurements altogether, then you reduce the audio experience to one of taste alone. If you do that, this forum becomes nothing more than a place to share your enthusiasms. 

Speaking for myself, I appreciate posters like Erik Squires because they provide more than mere opinions, more than mere personal preferences. There are correlations between measurements and subjective listening which, at least in principle, bypass the pitfalls of mere judgments of taste.

Thanks to everyone for the responses. So it seems like a narrow dip in spl at one point in the range is relatively inconsequential, at least in this instance. That's good to know.

@roadcykler, your post is surprising on an audiophile forum. Whay do I want to hear the dip? Because I want to be able to correlate the measurements with my listening experience. Or in this case, to learn that the the dip has little effect on what I'm hearing. If none of this was important, I'd just buy some old Pioneers at the goodwill and be done with it. I like learning about audio almost as much as I like listening to music -- it's how I put together a system that presents the music at its best.

If you can’t hear it, you can’t hear it. don’t force yourself to.

MANY speakers have ragged response graphs far worse than this, and they are often credited with being "revealing" and making the reviewer go through their entire music catalog again as if they are hearing the songs for the first time. Amazing!!

What actually happens is that the ragged response makes some notes pop more than others, tricking your ear into believing it to be more revealing, and it is, but only in some ways.

This is overall a very smooth measuring speaker, with the potential for excellent off-axis performance and dynamic range. JA at Stereophile has certainly praised a number of speakers that measured far worse.

@erik_squires , thanks for your input on this thread!