I always get the feeling that the Kryptonites (as outlined by Doug Purl on the bass and DIY loudspeakers mailing list) are constantly testing every other variable in the reproduction chain and they never seem to be at fault. Properly set up and with sympathetic ancillaries listening to these speakers is an event. I have never been entirely happy with any of the speakers that I have owned in the past: Apogees, Duntechs, original (but modified) Quad electrostatics, Acoustat 1+1s, Audio Definitions, Allisons (4 plus the 1), Tannoy 15" (38.1cm) dual concentrics, KEF transmission lines, Lowther Acousta horns and Magneplanar Tympanis. I have liked certain aspects of each of these speakers in the past: Apogees on voice, Duntechs for image height and solidity. Original Quads (sans grills/damping material behind panels and placed in a D'Appilito configuration on rigid stands) for almost everything except macro dynamics, lack of impact and bass quality and response. Acoustat 1+1s for image height and pinpoint image width, Audio Definitions for the bass, Allisons (model 1) for smoothness, the honeyed tweeter and the feeling of unburstability, Tannoys for macro dynamics and impact. The KEF transmission lines have good upper bass plus pretty good bass extension and the Lowthers for their micro dynamics and life. The Magneplanar Tympanis were fairly coherent and had a nice treble.
After living with each of these speakers over a period of time various perceived shortcomings become apparent. The Carvers so far have not. They do all of the hifi buzzword things incredibly well showing almost all of the strengths of the above mentioned speakers with none of their perceived weaknesses. The only gnawing doubts I have are that the bass although it goes much lower than any other speaker I have ever heard, with or without subwoofers, seems to lack the impact and punch that horns and some bass box enclosures can have. The bass through the ribbons/woofers is perhaps more natural; certainly incredibly detailed, coherent, uncoloured and effortless but sometimes I want more punch and slam that a few of the above mentioned designs exhibit.
However I do not mean to suggest that these speakers will be to everyones taste. Something like a Tannoy 15" (38.1cm) dual concentric in a large enclosure sounds like you are in a recording studio listening to a live feed over monitor speakers from the recording session in the next room. Altec 15s with large sectoral treble horns (as used in theatres to produce a sound which pins you to the seat) sounds like Pink Floyd (or whoever) is in your listening room with a stack of PA bins in front of you, warts and all. The Altecs have a live, hard hitting, very resolving and incredibly dynamic sound coupled with a visceral quality that I have not heard before. So it's horses for courses as they say.
These ribbons are very special. They are the only speakers that I have listened to that have such a formidable suite of strengths: dynamics, bass to midrange to treble blend and tonal accuracy (which is crucial in my list of listening priorities), delicacy, vocal clarity/articulation and massive soundstage. These are the only speakers that I have come across that when I put on a recording, if it is of sufficient quality, before the music begins you can sense the size of the acoustic space in which the recording took place. I suspect that this may be due to their dipolar nature and sensitivity which is higher than any other dipole that I have heard coupled with outstanding bandwidth. This experience is the same as when one enters a huge cavernous space such as a large auditorium, church or mine deep below the earth and you can sense the size of the acoustic space.
A valuable strength of these speakers is that they faithfully track the ebb and flow of the music, not changing their character as the music gets louder. Every other speaker I have heard changes its sound to some extent as the music changes volume. I think that this is a very important aspect of music reproduction where most speakers seem to have gross shortcomings. The frequency spectrum is handled in a very even handed way; the dynamics, power and transparency being consistent throughout the entire frequency band.
In Bill's listening room the Carvers have a huge sound stage and are magnificent on large scale orchestral or opera material, however, though still front rank, not as good on small scale works. The bass in Bill's listening room lacks power and impact. In Bill's listening room the sound is very detailed and free breathing with lots of air, and space around instruments with the rear wall, side walls, floor and ceiling reflections being reproduced if it is on the recording, but the sound for me is a little too hifi and artificial sounding and slightly brittle. Transients in Bill's listening room can be very sharp but the power range of the orchestra is too thin, weakening the timbre of some instruments. I think that this bright thin brittle quality is for the most part due to the very live room.
After what Bryan has written I'll just add my own extra thoughts as I concur with practically everything the Bryan has written. Bryan, having younger ears than mine, can hear above the highest frequencies that I can hear (which can also have its problems) and coming from a different background he listens for different things.
Many attributes of the sound from the Carvers show up the excellence of the Carvers: the lack of image height, the depth and width of the stereo image, the coherence of the system, the resolution and accuracy of the sound and the lack of room interactions other than the back wave. Stereo recordings cannot record image height and thus when played back shouldn't have any image height. More information on how to record/reproduce image height can be found on the ambisonics WWW page. The lack of image height of the Carvers is due to the lack of room interactions and lobeing. Multi-driver Duntech Black Knights in this same room could give plenty of image height because of these faults. The Chesky Test CD 1 (Chesky JD37) with the LEDR test for image height does appear to have some small image height with the Carvers but nowhere near as much as on all other speakers in this room. The Chesky LEDR test for image height appears to be bursts of signal covering the whole frequency spectrum with suitable notches in them between 8 and 12kHz to mimic the usual learned cues for image height. These notches mimic the typical cancellations due to reflections of sound in the outer ear when listening to something above and in front of you. You don't have the problem of the various frequencies coming from various "vertical" parts of the stereo image that multi-driver speakers have because with the Carvers everything is on the "one plane". This "one plane" also follows ones head height, moving up and down with ones head height unlike with box speakers where the tweeter is usually positioned to be at normal listening height and things change when you move out of that position.
The good depth of the stereo image is due to the dipolar nature of these speakers but the back wave from the reflective brick wall in Bill's place can also lead to brightness when the volume is turned up. Bill intends to try to cure this problem by adding absorptive material on the back wall. The large width of the stereo image is obvious in listening when you sit way back from the speakers. One note about the stereo width is that on the Chesky Test CD 1 where the speaker is way out on either side I can detect David Chesky way out on the left hand side due to what appears to be some room interactions on the left side but I can't detect him as being way out on the right hand side due to the lack of room interactions there where the wall juts out. My initial reactions to ribbons was coloured by my experience with Apogee ribbons where the sweet spot was but one head width wide and head height high. The Carvers don't have this problem due to their dispersion and you can sit quite a way off axis and still get a good stereo image, unlike with other speakers in this room like the Duntech Black Knights, but that is a long story.
One attribute of good speakers is that nothing should stand out as being unnatural and the Carvers excel here. It takes sometime to appreciate this fact with the Carvers because they don't initially grab your attention like other speakers but once appreciated I soon notice faults in other speakers by comparison. The ribbons are smooth, accurate and coherent and don't have problems like ringing metal dome tweeters. The accurate low bass performance of these speakers readily conveys information about the acoustics of the recording venue or the physical effects of low bass. I appear to have had more feedback about this from the Duntech Black Knights with two 12" (30.5cm) Dynaudio woofers per side mounted in a sealed box because they appear to have been bass heavy and could get down to house shaking low frequencies, room resonance modes and all, even if it was not too accurate. Some judicious boosting of the low bass in the active equalizer may give up even more information in this frequency range plus more punch to transients in Bill's room, not that the Carvers are too lacking here. Below the free-air resonance of the woofers at 22Hz the bass panels go off at the rate of 18db/octave and they become unloaded which can lead to large possibly harmful excursions of the woofers despite their long throw so one has to be careful in this low bass boosting. There are no problems with transients or impulses and this is where the coherence of the Carvers shows up. At Bryan's place with the panels further out in a longer room the bass was much better, being as much felt as heard and standing wave problems were setup. Doug Purl also reports that in his room the bass is also as much felt as heard. The woofers do run into problems with the claimed 5Hz and other infrasonics on Telarc's Great Fantasy Adventure CD (Telarc CD-80342), but I would not have expected otherwise of most speakers at this frequency. Telarc's Great Fantasy Adventure CD is a typical Telarc gimmick. I wonder how good conventional woofers in boxes like the NHT 1259 together with the Carver ribbons compare on low bass?
I listen by choice to only "classical" music. The Carvers do an excellent job in sounding exactly like the concert hall experience within the limitations of stereo recording. I am well acquainted with the concert hall experience. I have enjoyed immensely listening to many full orchestral recordings with the Carvers and can picture all the sections of the orchestra layed out in front of me on good recordings. These speakers readily show up the good and bad points in a recording or performance and be prepared for the bad aspects. Many recordings will be shown to have extraneous live noises in them due to the excellent resolution of the Carvers. The Carvers excel on the Chesky Ultimate Demonstration CD (Chesky UD95) and particularly on well recorded piano and similar transient rich recordings, the hallmark of an excellent speaker. I well remember hearing the Carvers for the first time on piano and remarking that the piano was in the room (the same thing occurred with some ludicrously expensive Genesis speakers with the same ribbons).
Some experimentation will have to be done to get the panels placed well. Putting them too close to the back wall will bring out problems with cancellation in the back wave. These speakers will always have some cancellation going on in the back wave and it is a matter of placing them as far out into the room for a good compromise with this, plus still using the room for listening and other things. The separation between the panels will also involve some compromises. If they are spread too far apart things may collapse in the centre of the sound stage but the stereo width will be large. Putting the panels closer together will decrease the stereo width and may be desirable for some small scale works (and addresses the problem that Bryan has noted and I too have noticed, a problem with dipoles) but not for other works. In spite of some initial contrary thoughts I haven't observed any problems with the relative positioning of the ribbon and woofer panels. There appears to be no problems around the crossover frequency of 200Hz between the ribbon and woofer panels after adjusting the active crossover. All usage of the ribbons so far has been done with them vertical and no attempt has been made to observe what happens when this is changed as suggested by Doug Purl. I note that in the Genesis usage of the ribbons they are also vertical. I plan to do some measurements of the Carvers when I have the necessary equipment but I expect them to confirm what my ears are telling me.
It is planned to mount the ribbons and woofers on better open baffles with more aesthetic appeal. After seeing a sample of Makassar ebony one could do better than Shun Mook Mpingo ebony discs and mount the ribbons in expensive ebony (and not the boot polish variety) and not have to piano lacquer anything. Perhaps wood winds and pianos and other things using ebony will then sound better. Expensive corian or polished marble or granite is another alternative. No, Australia has some beautiful decorative timbers like Tasmanian blackwood, oak and myrtle, Victorian mountain ash and satin box, Queensland walnut, quarter sawn silky oak, silver ash, maple, cedar and brush box, Western Australian jarrah, and she oak and all the richly circularly figured burls. 25mm (1") and thicker (32mm (1.26") or 36mm (1.42")) veneered MDF woofer panels are going to be heavy and sturdy. Bill plans to make the woofer panels in three sections with the two side panels mounted on piano hinges for folding back when they are not in use to decrease the woofer panels frontage. The sound when the woofer side panels are folded back could be interesting because we are in a different situation with regard to quarter wave cancellation on the baffle. Some experimentation will also be given to improved ancillaries and crossover and changing the crossover to judiciously boost the lower bass octaves.
It is hard to answer the question of where do these speakers rank compared to other speakers because comparative listening has not been carried out with the best speakers around and the possibility of this happening is small. I have listened to the large Wilson X-1/Grand SLAMMs and the Carvers overall were at least on a par with them despite the lesser bass punch of the Carvers currently and the Carvers are a great bargain when compared with the large purchase price of the Wilsons. It is interesting to note that the Wilson Grand SLAMMs, like Alons, are semi-dipolar. The knuckle test on the wondrous material that the Wilson Grand SLAMMs are made from, a proprietary phenolic material, sure shows how dead it is and it is to be hoped will make its way into other speakers, etc. It would be ideal for the Carver baffles. People listen for different things in speakers but it is Bill's opinion that the Carvers are the best compromise in speakers that he has listened to for his needs so far and things can only improve. A sure indicator of this is the fact that Bill hasn't felt the urge for better speakers after his experiences with other speakers.