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

I just want to add to @erik_squires comment. If you test your in-room response at the listening position you will quickly figure out why you are not hearing the narrow dip shown by ASR. By the time you put your speakers in your room and you add the reflections and absorptions in a normal listening environment the frequency response varies by a lot more than the dip you are concerned about. The audiophile forums are filled with stories by listeners spending huge dollars on room treatment to control these reflections/absorptions and finding that they made the sound worse.

And now for an editorial comment that will likely be unpopular but I just cant help myself. I think it's ironically wonderful that this thread is about not being able to hear a several dB dip in a speaker's frequency response but many members on this forum will report hearing dramatic differences between interconnects. When they describe what they hear they often use terminology that indicates large frequency response differences between two kinds of cables which, of course, don't show up in any kind of testing. This is an interesting hobby.

That cable comment is popular with me!
Also the remarks about room acoustics. I was going to write something of the kind myself. Room acoustics are at least as important as the speaker technology for the final sound.

@rischa - I bought my JBL 4349’s two years ago. I read extensively about these speakers before I bought them as you are probably doing.

I’d recommend simply to just listen to them and put away all the reviews, graphs, etc. I very much enjoy my 4349’s. Yeah, probably not an "audiophile" grade speaker in many people’s minds (a good friend has asked me why I have a pro audio "PA in my living room"), but I’ve had two years of really enjoyable listening. They will play at whisper quiet levels with much detail yet play at very high volumes that can be great fun. I too wondered about the dip in response that was noted in reviews, but that has not been noticeable by me or others that have heard the system in detail.

@jheppe815, glad to hear you’re enjoying your 4349s after two years. They’re definitely growing on me. Can I ask if you experienced a long break-in period? I actually bought mine used but I don’t think the original owner played then much beyond a brief audition period, as I know he had a few different speakers on hand to try at the same time as these.

Here’s mine:

Yes, I’ve asked myself several times how I ended up with PA speakers, lol. I think they look great, though.

With a dip of that magnatude in that area, you will hear a "dullness/flatness" in the vocals as though the overtones are subdued.  Many JBLs suffer from this.