In preparation for the soon to be expiring SVS pre-order, I did some testing of the various existing SVS cylinders. I myself have 1 SVS 20-39CSi. It is a great sub but I need more headroom and extension. So begins the quest. Sunday 19th My friend Eric had just received his dual CS Ultras. Our previous bargain had been that I get to borrow his Behringer Feedback Destroyer for 2 months if I showed him how to use it when his Ultras arrived. His room is in the basement, so the walls and floor are concrete. The approximate dimensions are 15x25x8 and it has an opening near the back to a stairwell leading upstairs. So a fairly large room and not sealed. The Ultras were placed in the front corners of the room and to start we plugged 1 port on each for a 16hz tune. The amp is a Crown K1 (550 watts x 2). Next, I measured the response in Eric's preferred seat, middle row, center (he has 3 rows ). In the 16hz tune we were getting a 10db hump from 16-22hz and from 22+ it was fairly flat except for a 10db peak at 46hz. No dips luckily. We set a band on the BFD and the peak at 46hz was easily dispatched. So fairly flat now except for this 10db hump at the very bottom. First up was The Rundown - first fight scene in the nightclub In the 16hz tune, the dual Ultras measured 108db (c weighting / fast) on the Rundown "bodyslam". It was clean and could be felt through the air and in the chest. Shirts and pantlegs were flapping. So of course the next thing to do was hear it again only louder . We upped the volume and tried it again. 109db, but I detected what sounded like the dreaded clack. It was faint but once you've heard it, you never forget. Up went the volume again, 110db measured and very noticeable beginnings of clacking. Now we removed the plugs to return the Ultras to the 20hz tune. Same volume as the last test and we hit 113db. Clean as a whistle and the first time my hair actually vibrated. At this point I have to say that the sound character between the 16 and 20hz tunings is significantly different. At the 16hz tune this is probably the best sound quality I've heard from any subwoofer. It was deep but totally composed across the 15-80hz range. It had that silly "tight" description that most "audiophiles" like to tag on their wimpy 10" subwoofers that do nothing under about 35hz. I was actually a little disappointed at how the sound character changed in the 20hz tune. It shifted from being more visceral and tactile to being more of an audible effect. It didn't sound bad at all but compared to the fantastic sound character at 16hz tuning it was slightly less impressive. Louder but not as visceral and deep. From here on we left it in the 20hz tune as the 16hz tune just ran out of gas too fast in his room. Next up was Titan A.E - the icefields. Hmmm. I have to admit at this point I was a little unimpressed. There was gobs of output but the bass content of this scene is rather one-notey. I counted at least 15 bass FX that sounded the same, as if they had cut and paste the same effect again and again. There is certainly quantity of bass but it just gets boring to hear the same tone over and over. Similar findings were made on the other subs so it wasn't actually the fault of the Ultras. We quickly tossed that scene from the demo list. Next up was The Matrix Reloaded - fight scene with many Smiths. This really sounded fantastic on the Ultras. I was measuring peaks of 111, 113, 112db all throughout and you could hear the various kinds of bass. Short punchy bits from single kicks and punches to quaking rumbles from the foot stomps. Some of the most impressive bits were the sustained bass when Neo spins in slow-motion with the steel pipe. They only read 108-109db but the sustained nature was totally smooth and controlled. I didn't push the volume any higher at this point but I would estimate that we could easily do 116db peaks with the same composure. 118db is probably the upper limit of a pair in 20hz tune. Overall impression: Fantastic sound quality. The 16hz tune was bar-none the best bass I've heard. The output was a bit crippled but for most people it would be plenty. In a smaller room you could probably reach the 112-115db range. Quad Ultras in 16hz tune would truly be awesome. For bigger rooms or SPL hungry listeners, the 20hz tune is the way to go. We were sitting in his middle row, which is about 12' away from the Ultras and you could feel waves of bass. In the Rundown and Reloaded, the Ultras defined the bass notes so that you can appreciate the intricacy of the mixes. That's really what it's all about. Loud, deep bass with the ability to reproduce the subtle differences in tone. Monday 20th Now of course the first thing we all do after hearing/seeing something impressive on someone else's home theater is to try it at home. My room is 10x12.5x8 with only 1 door that can be closed. My theater is on the first floor however so the floors are wood joist and the walls are plaster (old house). I have a single SVS 20-39CS powered by the Samson S700 and eq'd by the ART351. This is where things get depressing. On the Rundown I could reach about 101-102db on the "body slam" but the sound quality was getting ragged. It definitely did not have the punch of the Ultras. The Matrix Reloaded sounded better but peaks were still only in the 103db range and above that it was losing control. Titan A.E reached similar levels and I noted again how little the bass notes vary in the icefield scene. I turned everything off and left in relative disgust Luckily (for me), while at my friend Eric's place, we measured the frequency response of the dual Ultras with and without his old 16-46CS+, which was at the back of his room. Our hope was that it would help to smooth out the response of the dual Ultras at the front. Unforturtunately, it just made the response worse and it added very little to the output. Theoretically, the best it could do is add 3db if placed at the front and that was not physically possible so it had to go at the back. In light of the excellent performance of the Ultras by themself Eric decided that he had no use for the CS+. Being the generous guy that he is, he offered to let me try it in my home theater in case I wanted to buy it before tossing it on Ebay. Wednesday/Thursday The first thing I did was to run the 16-46CS+ by itself to get an idea of what it was capable of. It is a significant improvement over the CSi. The better driver has greater control in the 16-25hz range and I was able to hit about 104-106db with reasonably low distortion (not a lot of harmonics). It was significantly better than the single 20-39CSi but it wasn't quite reaching the levels I wanted. So next up I experimented with having both subs connected. 1 in the front right corner, 1 at the back left corner (I don't have too many placement options in my little room). That sounded rather crappy as even at 80hz crossover I could detect a sub behind me. I settled on having them together at the front right, which nicely blocks the door from opening fully The other tricky part is the mixed tunings. Normally I filter at 19hz and down on my ART351, but the 16-46CS+ should be filtered at 15hz and down. I compromised by setting the subsonic filter at about 18-19hz and I reduced the gain slightly to the 20-39CSi so that it isn't pushed as hard. Result? Clean peaks of 108-109db in the Rundown "body slam". I hit as much as 110db but I can hear the sound quality diminishing. Neither sub was clacking at all but you could hear the loss in definition. In my room the slamming bass type effects tend to ripple through the floor since it's a wood joist construction. It certainly makes body slams and foot stomps seem real but you lose that in-air, wave of bass effect. It could also be that the CS/CS+ combo is unable to move enough 15-20hz bass to get that effect. Can't say unless somebody brings over a pair of Ultras Friday What better litmus test than a pair of Servodrive Contrabasses backed with 1400 watts His room is also in the basement, 11x21x7 (goofy low ceiling in basement just like my 1950's house) Before listening, I measured the frequency response of the 3 main seats. The 2 seats in the middle of the room had fairly lumpy response, humps from 20-25hz, valleys from 30-45hz, another peak at 45-55hz. The seats at the back near the wall however, were virtually perfect with even a slight house curve established (shelf from 20-30hz, sloped down 8db to 80hz). This is where I sat for most of the SPL measurements. To start, I asked my friend Andrew to turn off one of the Contras. This made it easier to assess what 1 was capable of. As always, we started with The Rundown. The bodyslam registered 114db. Yowsa! So of course we now increase the volume 116db! More. The needle swung past +6 to what looked like +8 if that's possible. "so why do you need a pair of these again?" I went and turned the 2nd Contrabass on. This time the needle nearly snapped off. I had to set the rat shack meter to 120db range and we played it again. 122db! The ceiling is creaking, walls are bowing/rattling. Basically anything not made of cement is making a nuisance of itself. The Contras are laughing at us, "we can do more". It should be noted that this still doesn't sound harsh or ear-splitting because the majority of the SPL is infrasonic bass that is felt, not heard. If you hit these levels at 500hz+ your ears would bleed. With bass, it's just a room-rumbling, shirt/pant flapping affair. Did we go louder? No. At this point it was just getting silly and the room was adding so much rattling rubbish that it maybe even detracted a bit from the presentation. Having heard Eric's super tight basement, I like that the best. Nothing rattles and you get almost the full force through the air. It is pure bass at it's finest. Now of course the ultimate question, which sub is the best? I won't make a judgement like this since they were all used in different rooms. Each was measured and equalized for a reasonably flat response but the size and room construction vary too much. I can make some conclusions on each. 1 CS - enough for small rooms or those who don't listen at reference level 1 CS+ - absolutely worth the extra cost. Greater control, stronger extension, just better sound quality all around. CS & CS+ - this is where you start to get that true bass impact. No movie theater I've been to comes anywhere near the 20-30hz output of this combo. 2 CS Ultras - bloody good. The 16hz tune puts them at the top of anything I've ever heard. The 20hz tune isn't quite as defined and deep-digging but it can hit you with impressive impact and waves of bass, even in a fairly large room. 1 Contrabass - similar to dual Ultras. Has the extension of the CS at 16hz tune but the output of the 20hz tune (probably more even). Not quite as good sound quality, but that's difficult to peg down given different rooms. 2 Contrabasses - you better have a well built house or you'll be hearing so much vibration and rattling it will be somewhat distracting. Easily the king of output, maybe not quite the best sound quality. Hard to make a rock solid conclusion when they are in different rooms. 1 20-39CS - $429 1 20-39CS+ - $575 1 20-39CSU - $899 1 Contrabass $3000-3500 2 CS Ultras matched up well against a single Contrabass, although the Contra has a very big edge below 18hz. 4 CS Ultras in 16hz tune are probably in the same ballpark as 1 Contra for a total price of $3600. I doubt most people would hear much difference or care at this level of performance. The CS and CS+ combo is not something I would recommend. Mismatched tunings is also something I would absolutely avoid. For small to medium rooms a pair of CS+ will definitely kick a lot of ass. This is why so many people are happy with the PB2+. The Ultras are absolutely worth the extra money however. The price premium is significant but the payback in performance is worth it. The regular CS is still a great sub, it really just depends how loud you like your movies, budget and room size.