The PIR always is a bit lower in the bass. It is more representative of those people who have their speakers like 5ft off the front wall.
The distortion graphs are done in-room, but near-field (Amir did the original tweeter axis, so ignore the treble region):
It can be called “flat” down to 50Hz. Keep in mind though we don’t like bass that is flat in room, 20Hz should be at least ~5dB higher than 1kHz, which in turn should be somewhere around 5dB higher than 20kHz.
If the PIR represents speaker at 5ft/1.5m from the front wall then it's useless for those of us in the UK and in many European homes.
The actual in-room response does indeed look closer to JA's LW plot yet different from the PIR.
It is not wrong to conclude that the PIR plot does not reflect the IR of dipole speakers with the necessary accuracy.
So much of this ambiguity/debate could have been avoided by doing a one minute RTA sweep at MLP using REW as a sanity check on the Klippel and near-field measurements and to set the context of what the listening test was actually hearing. To supplement the other measurements.
I strongly suspect that this measurement would have shown something similar to the SMGa measurement I posted earlier but with relatively flat (but not necessarily smooth) extension down to 50hz instead of the 100hz and likely a less of a hump around 300hz.
My take based on my interpretation of the data available for the LRS so far and some experience with the small Magnepans:
The LRS is just fine as is for acoustic, small band, chamber music, jazz trios, etc. Or if your hearing/sensing ability is falling off faster than the speaker below 50hz. EQ any measured hump around 300hz down if it feels a bit low-mid heavy relative to high treble hiding the upper details. Use its attenuation resistors if it sounds too bright to your ears.
For bigger ensembles, clean music with content with details in the extended low, supplement with a sub crossed over at 60hz, and optionally EQ a small room gain as preferred (by keeping the sub at a slightly higher volume relatively)
For HT, rock/pop/metal, etc., supplement with sub crossed over at 80hz, sub dialed in higher to have a 3db-6db room gain and smooth out the downward slope with EQ.
It will hold its own within any speaker in its price range (including any required stands for book shelf speakers, subs, etc). Subjectively, it might even sound better depending on one's tastes and room.
The main downside of these small Maggies is that it cannot be optimized to do well in more than one of the above categories of music if you listen to mixed genres.
To get appreciably better experience or versatility, you would likely need to go to the $1k+ range either with the Maggies or something else. Or you can live with these for decades as many Maggie owners do.