See my sonic comments on the Walsh 5 Series 3/4 in a more recent thread, "Ohm Walsh 5 S3."
Mamboni had reviewed the Walsh 5 S-3 in Audio Review before I purchased mine. I have never been able to approach the measured flatness of response he gets in his room. There is a strong peak in my room in what I label the lower midrange, between 150 and 300 Hz, seemingly a floor-to-ceiling mode resonance since it doesn't vary much with room placement. In another room with a drop ceiling and insulation above that, this peak is not really apparent unless you are listening for it.
I think that the Walsh speakers work better than most modern speakers with a wall close behind them. John Strohbeen told me he designs them for placement about two feet from the wall behind them. As Mapman says, in such a position they act like a video or sound projector onto the wall behind them, but there still is excellent depth of field, unlike most speakers so used. In my main audio room, I oscillated between having them set up firing into the long dimension of the room with eight feet behind them to the wall, and firing into the short dimension with the long wall only three feet or so behind them. The bass response was far flatter but not quite so extended the latter way.
Bass response is quite extended. In my room response is only 4 dB down at 20 Hz with the speakers firing across the short dimension. Firing into the long dimension, response does not fall below the 1 kHz level unti 16 Hz. Yes, the JL Audio subs add yet-further extension (flat to 10 Hz) and punch, but for the size and price the Walsh's bass extension is uncanny and unmatched in my experience.
The debate over whether the Ohm CLS driver is a real Walsh driver is pointless. No original Walsh driver could play as loud or cleanly as these could with any amount of power behind them. You needed 200 watts to drive them to moderately loud levels and less than 300 to break them. And beginning with the Series 3 CLS drivers, the amount of power needed for high SPL and great dynamics decreased greatly. With my Series 4 prototypes, driving them loud and clean is now child's play, well within the capabilities of a modest home theater receiver.
As to coherence, the Walsh S3 and S4 drivers sound like a one-way speaker. The single capacitor crossover to the tweeter at 8 kHz is not audible. Period. They are like Quad electrostats in this respect and far better than Magnepans. Only a very few other speakers I've heard can be listened to in the near field (as I often listen) without hearing out the individual drivers.
Calling the driver a "line source" IS a stretch in terms of the driver dimensions. However, if you listen from back as far as the speakers are apart, the name makes sense. The apparent sound source expands vertically to fill the floor to ceiling distance, despite the fact that the actual driver is less than a foot tall. You have to hear this for yourself to believe it. And if you listen in the near field with the speakers far apart, as long as you listen at the correct height (ears just below the top of the driver can) they sound like pulsating sphere point sources, disappearing into a very coherent, open soundstage.
My only sonic caveats about the Ohm Walsh speakers relate to what I mentioned in the other thread. They share, with all other wide dispersion speakers, the quality of imposing more of your listening room's acoustics on what you hear than narrower dispersion speakers do. Whether that is bad or good, you have to judge for yourself. Many find such designs sonically very attractive since they make all music sound big and very open. Combine this with the very canny tonal balance Ohm has chosen and the other qualities of the CLS driver and you get a mighty attractive total package of coherence, generous warmth, space, relaxed openness, size of presentation, and extended highs and lows which I've labeled the audio equivalent of comfortable old shoes.
No, they are not the last word in nuanced detail either spatially or in terms of what is usually labeled "transparency," but they are not slouches in these areas. No, the cosmetics of the driver can are not the best, but the grills look very nice and will cover that if the look of the cans bothers you. The binding posts did not take kindly to ProGold, so I replaced them. The driver cans form a death grip with the cabinet once screwed down and are very difficult to remove when necessary, as when one of my CLS drivers developed a case of high distortion and needed replacing. I do not find the switches useful, but then I have a TacT RCS 2.2XP to handle frequency tailoring; users with such tonal control could save $1,000 and buy the 300 without the switches. Nothing men make is perfect. The particular set of compromises Ohm has chosen here will please most users a lot, I think.