Imo there are general design attributes which can contribute to a speaker sounding consistent (and hopefully consistently good) from one room to the next.
If the reflected or reverberant energy sounds like the direct sound, then whether the room returns a little or a lot of reflected energy, and whether those reflections arrive after a short reflection path (small room) or a long one (large room), the in-room sound will at least be similar. This is generally true north of the bass region; we’ll come back to the bass region in a minute.
The most obvious way to get the reflected energy to sound like the direct sound is to use an omnidirectional speaker. However this can result in too much reverberant energy in the room. Often uniform or otherwise intelligently-controlled dispersion over a less-than-omndirectional angle works a bit better in smaller rooms.
In general a wide-baffle speaker is more consistent from one room to the next than a narrow-baffle speaker. This is because wide-baffle speakers require less baffle-step compensation, and baffle-step compensation increases the relative amount of off-axis energy in the lower midrange region, which in turn typically increases the spectral discrepancy between the direct and reverberant energy.
In the bass region, the boundary reinforcement situation differs so much from one room to another that either a significant amount of adjustability or relatively room-insensitive approaches are beneficial. For instance, a powered subwoofer system can be adjusted independent of the rest of the spectrum, and is therefore relatively room-adaptable.
Here are a few specific suggestions of speakers which are particularly good in a wide variety of rooms. This list is by no means complete; consider these to be examples of approaches which work well, rather than being definitive answers.
The Gradient Revolution combines a uniform-directivity coaxial mid/tweet section in a cardioid enclosure with an inherently room-boundary-insensitive dipole woofer section. Other Gradient models also take room interaction into account much moreso than most speakers.
The Dutch & Dutch 8c uses a constant-directivity waveguide-loaded tweeter + a cardioid midwoofer, mated to a sealed woofer section, employing powerful DSP to integrate the drivers with each other and, in the woofer region, with the nearest room boundary.
The Snell Type A may have been the best wide-body, room-boundary-friendly cone-n-dome design ever. Sadly discontinued, it is worth taking a look at as an example of how to do it right.
MBLs are probably the most well-know true omni (in the horizontal plane at least) speakers, but ime they tend to sound best in large rooms where the early reflection path lengths are fairly long.
The fullrange SoundLab electrostats which use a 90 degree pattern have arguably the most uniform radiation pattern of anything that’s not a true omnidirectional, and their inherently reduced sidewall interaction makes them more smaller-room-friently. Like all dipoles and bipoles, they sound best with a fair amount of distance between them and the front wall. Imo the 45 degree pattern versions offer a worthwhile improvement with their higher direct-to-reverberant sound ratios, at the expense of some sweet spot width.
The Revel Salon 2 and many of its smaller siblings are specifically designed to produce an off-axis response which tracks its on-axis response closely.
The PiSpeakers 3Pi is an imo excellent and affordable underground giant-killer woofer/horn hybrid loudspeaker which gets its pattern control from a large diameter midwoofer + a very well-designed constant-directivity horn.
The Larsens are designed to go right smack up against the wall, as is the Sjofn (the clue), so while not necessarily adaptable to a wide variety of room situations, these offer viable options for specific/difficult situations.
As you can probably tell room interaction is an area that I think matters. In general my approach is to use a fairly uniform-pattern front-firing horn/midwoofer array combined with an adjustable rear-firing array, with either a user-tuneable bass loading or a separate subwoofer section.
The above list is by no means comprehensive.
Duke
disclaimer: I am or have been a dealer for some of these.
