Well, I have them with about 200 hours time break-in. They are (as were the Quatro's) really strange during break-in. Remember, I changed the amplifier, preamp and speakers at the same time. The pre-amp was in my Quatro system, so I know the XP-10 is generally a very detail oriented pre-amp with a softer bass response compared to the MAP-1 used with my Quatro's.
That said, the speakers went from BRIGHT (first listen) to veiled (maybe a hundred hours) to an odd BEAMING midrange that went literally straight into the room and had NO dispersion up or down. You could move your head in, then out, of the BRIGHT beam of sound...ODD is an understatement.
What was it? I haven't a clue. Could be the amps or the speakers or both going this way and that. But noiw, the speakes and amps seemed to have settled down and are very listenable. I can say that the C4's couple energy into the room like crazy. I mean this in a good way.
Most speakers are best in a sort of near field sitting position (Quatro's) where you are about set-up in an equilateral triangle with 7 or 8-foot sides…seven or eight feet between the speakers, and about seven or eight feet from YOU to each speaker.
The C4's do NOT like this. The imaging is good, but if you get BACK away from the speaker some, maybe to a fifteen-foot distance from you to each speaker, the imaging is MUCH better. The Quatro didn't like toe-in in the near field set-up, the C4's likes some toe-in.
I have the C4's about seven feet apart, and sit fifteen feet away from the front plane of the speakers. The C4's are 5.5 feet from the rear wall, and three feet away from the one sidewall. The left speaker is OPEN to the "L" end of the room. So, even at fifteen feet away from the speakers, I have about twenty feet of room behind me. The room is 39 feet long and 13 feet wide and 8.5-foot ceiling.
Once you realize that the C4's are really able to fill a BIGGER room (mine is over 4,000 feet squared) the comments on the speaker all make sense. Even sitting back away some, the C4's is RIGHT THERE imaging. The effortless solidity of the imaging make the left to right sound seem HUGE.
I haven't gotten the SMcAudio RDL-3000 (well, it' and RLD-1 I spent $3,000.00 on!) back just yet, so I can't comment on the bass. The XP-10 continues to be excellent above 200 HZ, but is softer than I like down low. What I can say, is the C4's will pressurize a room with male vocals and send them right into your chest! Put a Gordon Lightfoot CD or album on, and you resonate to his voice deep inside you! The C4's just flat couple to the room and takes control. And this isn't at 100 dB either. I listen at maybe 60-85 dB average SPL.
I have never heard a speaker that can do this in the midrange in a room like the C4. It is simply fantastic. Sure, the OSYSSEY MONO KISMET amplifiers can't be too bad and get a sound like this out of the speaker. No, the KISMETS aren't super expensive amplifiers, but WOW, they sure sound good for the money! They are smooth and effortless sounding on the C4's and are very good for solid state amplifier. I'd say it is probably much like a Steve McCormack platinum modified DNA-225. I say this because my STOCK DNA-225 was harsher sounding than the KISMETS, and the reports on the DAN-225 platinum modifications are remarkably like what I hear in the KISMETS. I do like Steve McCormack electronics, too. This is why I sent an older RLD-1 to him and let him uncork the sound in a good design held back by cheaper parts.
Once you get past the C4's superb midrange coupling to the room, the highs are just not there. Not there? Yes, they are so good you just don't hear a tweeter, you hear MUSIC! This is the way it is supposed to be. If you like to hear each speaker, you won't like the C4's. The are a disappearing act. The driver integration is excellent.
The go DEEP all right, but the XP-10 holds it back (It did on the Quatro, too). So I can't comment on the bass just yet. To be fair, if you listen, or like, a firm but not overpowering bass, the XP-10 delivers the goods. Me, I like the bass to beat me up if it is supposed to! The C4's did that with the right pre amp when I auditioned them. Was it too much bass? NO, it was dynamic and properly fielded bass that fit the remarkable midrange energy.
OK, what's not to like? The Quatro had a MAGIC female midrange that is so far impossible to beat. The time and phase alignment of the Quatro allows a superbly layered front to back sound that almost lets you see the vocalists tonsils. The C4 gets the width, depth, height, and energy more correct in size and quantity but it can't capture the layered front to back micro dynamics that the Quatro can. The ability to form a near field halographic layered image is a Quatro strong point. It can not be denied.
The Quatro with those SUPERB sub amplifiers, and equalized to your room, and with 250 watts of class B power go DEEP in spades. The C4 excels in POWER and dynamics, but the Quatro can roll out the bass floor all the way to hell if need be. Bass down LOW is always a noodle or string being pushed up hill, it tends to "flow" and flow it does from the Quatro...and in the most beautiful way. The bass could be picked up in buckets it's so thick and deep.
The C4's bass is more like Jason from Friday the thirteenth coming into the room, takes his chain saw and slices the SOLID sounding bass up into cubes and start tossing them around on you. I'll have to see how the RDL-3000 (OK, RLD1 platinum) does down low on the C4's...but the Quatro may be hard to beat way deep (think MOVIE soundtrack thumps and bumps).
I LOVE the C4 II signatures! The overall sound is OPEN and expansive and really fills a large room correctly. The smidgen they give up to the Quatro is missed, but the improvement in OVERALL presentation is superior. The C4 II is far more integrated top to bottom as a single "speaker".
A speaker I DO NOT want to hear, would be the Vandersteen MODEL 7's. This speaker may capture all the C4's abilities, and add back in the wonderful female midrange layering and superb bass. THAT would drive me nuts wanting them! The seven's need POWER and electronics, too. The sevens for the price are probably the deal of the century, but I'm a lot poorer in the century that they were created in, darn.
So I can't afford the sevens, and the model 5 Carbons are also too expensive. So I moved up to the C4 signatures and couldn't be happier in my room, and with modest electronics, too. And, they DO NEED ROOM. These aren't near field speakers. No, they don't need a stadium, but ten feet or MORE from the line between the speaker and your chair seems more like it with the C4's.
So in the middle to high teens, the C4 series II is a great product. The speaker is very colorless, it's like hot water (I said like, NO SPEAKER IS COLORLESS!!), it turns into what you ADD with electronics. The Quatro was a little like green tea, it had a great warmth to the sound that was ideal. So you need to watch electronics with each speaker. But, you can not REMOVE the Quatro sound where the C4's is what you play it with more so. It can go from brighter to warmer, your choice.
The ODYSSEY KISMET mono amps are a good old-fashioned basic analog design improved over the years. They have HUGE capacitor banks and transformer (they are heavy) and they have a TON of current delivery and match the C4's very well. Heat isn't an issue, they just don't get warm, are DEAD quiet, and you never notice you have amplifiers, just music. So their neutrality is good. I use less than 30" of Groenburgh Quatro reference extreme speaker cable as the amps sit right by the speakers. You can buy KISMETS in Stratos cases and save some money if you want to, Klaus builds to suit. Mine are deep maroon red front and top panels with black heat sinks along the sides, and are strikingly nice sitting on the floor by the bordough (maroon) C4 II signature speakers.
KISMETS have a smooth effortless and nice sound that isn't my sonic bottleneck, I need a dynamic harder hitting preamp! These amps won't be on Audiogon soon, sorry. I won't argue $10,000 SS amps isn’t better, but I will argue that there is little the KISMET mono amp leaves on the table compared to ANY amp in their price range. And probably, will be near the top of the heap of amps costing much more through distribution channels. It turns out that they were a very easy decision, a solid piece of quality electronivs at a nice price. Doing it very well for cheap is hard to do till the KISMETS make it "sound" easy.
I'll have to comment on the RLD-3000 (you should know I call the platinum RLD-1 this by now!) in a separate post after it works in some. But again, I went for a BASIC superior circuit uncorked with better parts by the man who should know what to do. Doing it well for cheap is hard, till you find the real audio pros. Steve McCormak is the real deal.
You may ask WHY I sold my MAP-1 and DNA-225 when I could have SMcAudio modded them. Good question. I sold them with my Quatro's to a friend who can't afford what I can. I have a soft spot to help someone out less fortunate than I, and who truly loves to listen to music so I let them go, knowing they will make him happy, and HE can later as his finances allow, upgrade them. But darn, that MAP-1 sure was good on the low-end of not as open as the XP-10. Steve assures me he's going to fix that. The KISMETS sounded (and I was right) like the best way to get two mono amps that excel at what modded McCormak pieces do...and maybe better. The C4's II's will rip a poor amplifier apart and leave it for dead sonically. I hear music with the KISMET monos.