I posted some comments about the SVS 25-31 PCi I just bought in the classifieds. It seems a better place for discussion is in it's own thread here. I thought I knew about SVS subs and they looked simply named. I knew Iain J was keen on them, but I was previously put off buying because I was overwhelmed by the 6 models to choose from and that I couldn't audition one locally, as there are no distributors, as SVS only sell direct, from the US. Having agreed to buy this sub yesterday, I did an awful lot of internet reading before a 4 hour round-trip to get it. Thankfully the sub just fitted in the boot on my hatchback car and is now in-place and connected. All I can say is wow! I had previously home trialled an early REL Strata, I found that slightly boomy and ponderous with music and some films. Always sounded good on the Fugitive train crash Laserdisc, but a lot of other stuff made it get excited and blur the deepest bass over the actual music (i.e sub not controlled well enough) I bought a few books on the subject (The Loudspeaker Cookbook and Bullock on Boxes), read them and then auditioned and bought a Wilmslow Audio 2x 10-inch compound Isobaric ported sub (very clean, low-distortion) , run off a 2x200W Denon POAT-2 THX Ultra power-amp (very, very clean, low-distorsion!). From measurements, this was managing about 32Hz relatively flat. Let's just say this 22Hz tuned sub goes much lower and surprisingly much, much cleaner, even though it's a larger single 12-inch driver. My gut feel is that I think this may be the answer to those with rooms that get over-excited by forward firing subs. Anyone near Berkshire want to try and I'm sure we can work something out for a small price of a cup of tea! I tried to set the peak sub-bass limiter on my Denon AV-amp, as previously had to set it to stop the THX Ultra amp bottoming out my Wilmslow sub's driver with a loud crack!. With the SVS, I gave up, as it got up to 0db, pushing 105dB on my sound meter, and my wife entering the garage to say the entire house was shaking (no, I'm not kidding). Let's just say 10Hz lower and a larger enclosure, better speaker driver don't sound much on paper, but in reality, they are. I ended up just listening to music till 1am. It really is another dimension and very musical. I can't wait to try some films. In fact I can't stop thinking about it, that's why I'm writing this. It's nicely freed-up the POAT-2 for 6.1/7.1 via my Denon A10-SE. The 25-31 is a tube cylinder sub, which from my previous sub reading means it's a strong shape for a sub giving great rigidity and allowing very efficient use of the controlling on-board amp's power. SVS also now make box subs, from their notes they are generally larger, heavier and more expensive for a given level of performance. The 25-31 is physically the shortest of the 3 cylinder subs, all of which are quite similar, they all look to be 16 inches diameter and all contain 12-inch high quality downward firing, long throw bass drivers. The 25-31 name is denoting the tuned frequency 25Hz and 31 is the height in inches. Well actually it's not, because SVS has a factory option of tuning any sub a few Hz lower, trading off a few max dB for a lower fall-off curve. In this sub's case, it's 22Hz, so actually a 22-31, but still called a 25-31! Kind of like the 323 badged BMW's are actually 2500cc. The middle 20-39 looks to be the most popular size with the Amercians (and Ian J!), allowing a 20Hz tune without the slight headroom compromise of the "22-31", just that it's 8-inches taller. The tallest is the 16-46 . Unsurprisingly just under 4ft tall and tuned to 16Hz. What is not apparent is that this lower tuned encloseure means this model has the a slightly lower max dB compared to the shorter ones. Each is available as a PCi or PC+ model. The PCi models have a 320W <mumble> high-current (class D? "BASH"?) amp, whereas the PC+ models have 525W variations with a custom alloy driver in place of the other custom one(!), surprisingly without a cast basket, which I've always heard was a GoodThing(tm) for a sub driver? The PC+ models also have user-removable port bungs that allow the end-user to swap the tuned frequency around a few Hz, again at the expense of a less flat fall to about 25Hz and sacraficing a couple of dB ultimate max sound level. From what I've heard from the "320W" PCi compared to my 400W THX Ultra amp driven Wilmslow sub, don't worry about power, the smaller amp seems plenty, really! From what I've read from the SVS and customer postings in the American review sites, any of these subs should be more than most UK domestic rooms will ever need for stunning, clean undistorted rhythmic sub-bass. And having heard the "smallest" one SVS do, I agree. There's a Secrets of Home Theater and High Fidelity review here http://www.hometheaterhifi.com/volume_9_4/svs-25-31-pci-subwoofer-12-2002.html There are lots of review and comments, but also lots of noise and fanboy and troll posts, under http://www.ecoustics.com/cgi-bin/bb...where=ALL&lookin=3&typepage=1&query=svs+25-31 The only three caveats I can think of if you are considering one: 1. Can you hide a large black kitchen bin sized upstanding tube in your room if not dedicated to HC. It truly is only sub-bass so may be one of the few that can actually be positioned behind or beside you, not just at the front. 2. The top plate is a grilled port vent straight down to the speaker driver back, so I'd not be in a hurry to place a coffee or flower vase on the top of it, no matter how nice it would look! 3. 22Hz sounds more like an earth tremor than bass. Even at -26dB listening level, those kick drums really do find their way everywhere, even the bedroom on the opposite side of the house to the converted garage on the next floor. Funny though, as you've no idead where the sound comes from, so evil owners of flats, terraced or semi homes might get away with it, for a while! Any comments or corrections appreciated. regards, Rob.