Came across this review if the KEF iQ90 and decided to add my thoughts on this wondrful speakers from KEF.
Music Genre: Jazz, blues and some classicals.
Pros: Good looking design. Like the curved cabinet. Functional too as the curved back minimize standing wave. Comes with plinth for stability. Clean highs thanks to the in-plane tweeter Uni-Q design. Sound stage is very good. Also very accurate. I can easily pin point instrumental positioning and vocals.
It's a holographic speaker. The iq90 just disappears once the music starts. Pretty awesome.
I've to say the sonic quality is more towards transparent. Not colored at all. Some might prefer a bit of warmth to it. These I feel are neutral speakers.
The room these speakers are in is fairly long. With my previous B&W 600 series I felt they didn't quite fill the room with authority. But iq90 never faltered at all.

Cons: Bass response does not correspond to its quoted spec. Not a big deal as I always run all my speakers with a subwoofer for the LF experience. Sometimes I miss the warmth and laid-backness of my B&Ws.

Overall: Being a B&W fan and owner for >20 year I did look into the 683. However I left feeling disappointed after auditioning them. It didn't quite capture me. For some reason, they felt generic kinda like any other main brand floorstanders. It might very well with the upstream gear used.

KEF decided to go all blocky with their new designs. I am disappointed by the company direction to follow other makers into designing boxy speakers. Oh well it makes the iq90 the more sexy. Hope to snag a Reference 200 someday!

I purchased my IQ90s at a bargain price as they were being replaced by the Q900. I had heard some KEFs at a local audio salon while actually shopping for another brand. I believe that first listen was to the IQ70s. I was very impressed with the midrange/treble clarity, overall balance and vivid imaging of those speakers. So when I saw the IQ90s being marked down heavily to clear stock for the Q900s, I jumped.

These speakers when in production sold in the neighborhood of $1800/pr. I purchased mine for roughly half of that. This purchase ranks right up there with among the smartest audio decisions that I ever made! I have three separate systems in my home - living room, music room, bedroom. My other equipment is all excellent - Magnepan(MMGs & MG 1.6s), ACI Sapphire III stand mounts, Response Audio(now Bella Musica - custom made) 50 w/ch EL34 based tube amp, McIntosh MC352, and my pair of Emotiva XPA-1 monoblocks(500 w/ch @ 8 ohms - 1000w/ch @ 4 ohms). The KEF IQ90s are in my main listening room - the music room. They are paired with my XPA-1 monoblocks and Emotiva USP-1 analog pre-amp(soon to be replaced with an XSP-1 pre-amp), Oppo BDP95 SACD/Blue Ray player.

I just love these speakers. The hype is true about these UniQ designs having a much wider "sweet spot" than typically arrayed driver designs. I can hear the output from both speakers easily at almost any point in the room. The IQ90s are positioned approximately 24" from the front wall, and 36" from each side wall and about 8' apart. My listening chair is positioned mid way between the two and approximately 9 - 10 feet from each. Each is bi-wired with separate runs of Audioquest type 8 of about 6' length. All interconnects are Kimber PBJ.

The imaging in this setup is positively holographic on well recorded material. I often listen at night in the darkness to this setup and when doing so, it is nearly impossible to locate the speakers. When in the recording, sounds literally emanate from all over the room!! I have an SACD copy of Pink Floyds "Dark Side Of The Moon" that is just mind-blowing on this system. All of my 24/192 audio files(I'm using an Emotiva XDA-2 DAC) sound incredible!! Steely Dans "Gaucho" sounds like I am literally sitting in on the recording session!! Every minute detail is revealed - a cough, feet shuffling etc. Yet the sound is very well balanced. Vocals are "in the room" with me real. Alison Krauss voice is just magical. Bass is tight and very well controlled. No "boominess".

This is one of the areas that most surprised me with the IQ90s. The IQ90s are reflex cabinets with front-firing ports. In the past I had found similarly configured speakers to have somewhat colored bass reproduction. Port noise was usually an issue. Not with the IQ90s! The bass is very tight and tuneful with nary a hint of port noise. KEF very considerately supplies foam bungs to block the ports if you so desire, but I have found no need to use them. I am very happy with the bass reproduction of these speakers. Maybe if you want that room-shaking bass for a home theater setup, you should consider a sub, but for music, I see no need whatsoever. YMMV, of course. Everyone has their own opinions on this.

Finally - esthetics. These are GORGEOUS speakers to look at in my opinion. Even in the black - which is what I purchased. Very sleek and classy looking. And the curved walls of the cabinet seem to do their job - there are no audible cabinet resonances that I can detect short of using an accelerometer. A knuckle-knock on the cabinet wall produces a solid non-resonant thwack.

All in all these are great speakers and a certifiable audiophile bargain if you can still find them. I am thrilled that I made this purchase. These are my first pair of KEFs, but they most certainly will not be my last!!!

Having listened to several speakers back in 2003. I eventually went with the KEF Q range. In 2010 I decided to upgrade to the IQ range. Major differences - The cones look really nice and the changed the speakers posts to this clear resin around the metal. The tweeter is also radically different. The base on the bottom does add some stability. I had the Q7 before and the weight is pretty much the same yet the Q7 did not seem as wobbly as the IQ90. It is very slight - compared to the IQ70 I got for the rears - which is rather bad. The build quality is not bad but just feel they a little top heavy. As for sound they sound typical KEF. I auditioned speakers from B&W as well as Paradigm. I also compared them to the KEF XQ range. I found the Paradigm Studios a little bright but awesome midrange. The IQ90 vs XQ40 was interesting...the XQ40 where better but I did not find them 3x better which was the cost difference. At best after 5 hours of comparative listening I would say maybe 30% better. Having lived with them for a while now I really do like them. The midrange and upper frequency is better than the Q7 but not the lower frequency. For the price however I found them to be excellent. If I could afford more I would have gone with the Paradigm Studio over the XQ but my KEF IQ90, IQ60c and IQ70 really do come to the party and deliver great in music and movies. You however will need a sub to get really good base. Get a 12 to 15 inch that plays down around 20Hz. I got the Paradigm SUB15 in my setup. Even the girlfriend agrees that there is far greater clarity in these IQ compared to the older Q. The Uni-Q setup that KEF uses does make a small difference in the sweet spot, especially at lower volumes compared to some of the other brands. I have bi-wired my front three and run them off a Yamaha. I have heard them off a Marantz, Onyko and Rotel. Sounds really good off the Rotel in stereo setup. They have just launched a new Q series which looks rather odd in the return-of-the-box format.