I've done a lot of near-field listening, as you can tell from my posts. The primary criteria I've found to be important for a speaker with a woofer, midrange, and tweeter arranged vertically to work well in this context is how much or little you can hear out individual drivers. You don't want to hear each driver as a separate sound source at different positions in space. If you can hear the drivers as separate sound sources, this interferes with imaging and staging coherence. If the woofers are far away from the midrange, and the crossover to the mids is not down around 100 Hz, you will likely be able to hear out the woofer/mid transition if you listen to such a system from the near field. The Harbeth M40.1s have their drivers closely spaced and are truly superb at this, sounding like one big driver from as close as two feet away from the front baffles.
If you do not want to apply high-frequency equalization, you also want speakers which sound naturally balanced in the highs from close up when they are toed in directly toward your ears. Near-field listening works better with the speakers toed in like that. Many if not most speakers will sound a bit or more brighter in this sort of toed-in, near-field set up than they do from further away. Again, the Harbeth Monitor 40.1s are extremely well balanced in the highs even toed in and from very close up--the tweeters don't stick out.
Other speaker types which work well for near-field listening include those with coaxial mounting of the midrange and tweeter. My Gradient Revolution Active speakers are superb from close up and toed in. Since the midrange and tweeter driver centers are at the same point in space, there are no different driver positions which could be detected. And since the crossover to the bass drivers is down around 200 Hz and is a relatively steep 4th order (24 dB/octave), the woofers really don't localize as a sound source in space too easily. I've tried and I just don't detect the woofer positions below the coaxial mid/tweet head unit, even though I also have a column of six additional Gradient woofers (the SW-T, "T" for "Tom" or "Triple" since I'm the only one I know of with such a stack) right behind the Revolutions.
The old Spendor SP1/2 is also excellent in the near field. Even better is the modern BBC derivative, the Stirling LS3/6. With both of these speakers, most of the sound comes from the 8" driver, which crosses over only above 3 kHz to the tweeters. Most fundamental tones thus come from that driver and the high frequencies are spread among two tweeters which are mounted close to the woofer and close to each other. The most natural sounding listening height for near-field listening with these is even with with the lower tweeter.
Another type of driver array that can work reasonably well in my opinion in the near field is any array which is symmetrical around a single point, such as a D'Appolito M-T-M or W-M-T-M-W arrangement. Even a speaker as large and with as many drivers as the Legacy Audio Whisper sounds quite coherent in the near field. In that speaker, the driver layout is symmetrical both vertically and horizontally. The manufacturer used to talk about that array producing a coherent "oval shaped" apparent sound source and I would agree.
But once the drivers are spread fairly far apart on the baffle, absent some sort of symmetrical array, you can pretty much assume that such a speaker is best listened to from at least a few more feet away--say eight feet or more.
The same goes for speakers with horizontally arrayed drivers like many Magnepans.
Large panel speakers generally will suffer some image height stretch when listened to from close up. All images will seem tall. Images may also be horizontally stretched or fuzzy. While some folks may like this "big" effect, since it is constant across source material, it is an effect rather than a revelation of the source material. Thus, even when the whole diaphragm is putting out all frequencies, it is best to listen to such speakers (e.g., the Soundlabs) from a "reasonable distance" rather than close up.
Finally, many "time-aligned" speakers (e.g., most Thiels) really should be listened to from eight feet or more back since the manufacturers and independent testing both indicate that the maximum time coherence between/among the drivers does not occur from closer up where the vertical angle subtended by the drivers is greater.
If you do not want to apply high-frequency equalization, you also want speakers which sound naturally balanced in the highs from close up when they are toed in directly toward your ears. Near-field listening works better with the speakers toed in like that. Many if not most speakers will sound a bit or more brighter in this sort of toed-in, near-field set up than they do from further away. Again, the Harbeth Monitor 40.1s are extremely well balanced in the highs even toed in and from very close up--the tweeters don't stick out.
Other speaker types which work well for near-field listening include those with coaxial mounting of the midrange and tweeter. My Gradient Revolution Active speakers are superb from close up and toed in. Since the midrange and tweeter driver centers are at the same point in space, there are no different driver positions which could be detected. And since the crossover to the bass drivers is down around 200 Hz and is a relatively steep 4th order (24 dB/octave), the woofers really don't localize as a sound source in space too easily. I've tried and I just don't detect the woofer positions below the coaxial mid/tweet head unit, even though I also have a column of six additional Gradient woofers (the SW-T, "T" for "Tom" or "Triple" since I'm the only one I know of with such a stack) right behind the Revolutions.
The old Spendor SP1/2 is also excellent in the near field. Even better is the modern BBC derivative, the Stirling LS3/6. With both of these speakers, most of the sound comes from the 8" driver, which crosses over only above 3 kHz to the tweeters. Most fundamental tones thus come from that driver and the high frequencies are spread among two tweeters which are mounted close to the woofer and close to each other. The most natural sounding listening height for near-field listening with these is even with with the lower tweeter.
Another type of driver array that can work reasonably well in my opinion in the near field is any array which is symmetrical around a single point, such as a D'Appolito M-T-M or W-M-T-M-W arrangement. Even a speaker as large and with as many drivers as the Legacy Audio Whisper sounds quite coherent in the near field. In that speaker, the driver layout is symmetrical both vertically and horizontally. The manufacturer used to talk about that array producing a coherent "oval shaped" apparent sound source and I would agree.
But once the drivers are spread fairly far apart on the baffle, absent some sort of symmetrical array, you can pretty much assume that such a speaker is best listened to from at least a few more feet away--say eight feet or more.
The same goes for speakers with horizontally arrayed drivers like many Magnepans.
Large panel speakers generally will suffer some image height stretch when listened to from close up. All images will seem tall. Images may also be horizontally stretched or fuzzy. While some folks may like this "big" effect, since it is constant across source material, it is an effect rather than a revelation of the source material. Thus, even when the whole diaphragm is putting out all frequencies, it is best to listen to such speakers (e.g., the Soundlabs) from a "reasonable distance" rather than close up.
Finally, many "time-aligned" speakers (e.g., most Thiels) really should be listened to from eight feet or more back since the manufacturers and independent testing both indicate that the maximum time coherence between/among the drivers does not occur from closer up where the vertical angle subtended by the drivers is greater.