Speaker and driver design at KEF

[amirm]

This video starts slow but then picks up steam and covers a lot of fundamental problems of designing speakers and how KEF solved them in their Uni-Q drivers.

Definitely worth a watch even if you are not interested in KEF speakers.

 

[Phison Audio - Sonny]

They most likely use something like the attached board with with a sigmadsp.
In this case we have 17 equalizer bands at 24bit 192ksamples.

That is the way to iron out the frequency response

 

[Soniclife]

Interesting video, I had no idea the uni-q driver was so different between models, and possibly why I've only loved the blades and not the lesser models.

 

[amirm]

Yeh, wish they had branded them differently.

 

[Deleted member 65]

Interesting video, I had no idea the uni-q driver was so different between models, and possibly why I've only loved the blades and not the lesser models.

Had the KEF XQ40 with Uni-Q drivers for Mid & Treble, hated it, sold on after a year or so ... could never listen to Bryn Terfel or a soprano with the KEF's. Decided to never invest in a speaker with metal drivers after the KEF experience.

 

[Soniclife]

Easy to see why they didn't though.

Also good too see proper r&d being done by a proper hifi company, whoever owns them now.

 

[Deleted member 65]

Built this KEF kit in the 70's, loved it ...

 

[Phison Audio - Sonny]

Built this KEF kit in the 70's, loved it ...

View attachment 8549

Its a classic set of drivers!

 

[sofrep811]

I owned one pair of Kef speakers back in 'o5 or 07'? Anyway, they were the Q1's and I bought them for about $180 NOS. They were not perfect, but in the right room (after moving system) they shined. I had them in a big chill room and they just didn't get everything to me fast enough. Switched to B&W 685s and they were a bit better, ree times the price. Sold those and have sold and bought about 8 different pairs since. I rarely make it a year without selling my entire system and rebuilding. That journey to me is the best part of Hi-Fi.

 

[amirm]

Welcome to the forum sofrep811. Didn't realize you could get a Kef for such a low price. My familiarity is only with their latest technology as we became a dealer for them for a year or so.

 

[sofrep811]

Welcome to the forum sofrep811. Didn't realize you could get a Kef for such a low price. My familiarity is only with their latest technology as we became a dealer for them for a year or so.

Thanks!

This gentleman I know who was a distributor for various brands 12 years ago and now just does custom high end HT jobs, but still reps several HT brands, still has at least 300-500 pieces of 2CH HiFi equipment he's been selling at nice discounts on audiomart.com the past year... I made an appt to visit and buy some gear -- all taxed and new unless it was a demo, with warranties. I took $700 hoping he had a older Rega around and some speakers, but since he didn't have a Rega and wanted too much for high end Woodpecker TT (think that's the name?) I picked around his inventory list and made a deal for $550 on a NAD 1050 USB DAC, NAD Viso headphones, and NOS Dali Blue 2002 speakers. Anyway, he still has one paid of the Q1's but they're floor stander speakers. The bookshelf I owned were very nicely made, nice drivers, etc. But either my amps at the time were too insufficient (Older Creek and then a Decaware DIY SET Tube amp and Lehman Black Box phono) and I was clueless back then to amp-speaker matching. I got lucky except this one time. Finally sold TT and bought an Opposition 93 and then it sounded much nicer, but the room was not audio friendly--three walls and a two door opening with slightly raised ceiling. About 120 sq ft room. I had to be sure I was stating the correct model of Kefs . Screwed up on attachment on IPad.

 

[Frank Dernie]

I am a long time KEF owner, and have met Jack Oclee-Brown when he gave a talk about the Blade in Oxford.
My first ever speakers were a pair of Wharfedale 8" RS/DD in simple boxes but as a second year Engineering student at Imperial College, London in 1970 I upgraded by buying KefKit 3s. The kit only required making the cabinet since the T27 tweeter, B110 mid and B139 woofer were already mounted on the baffle with the DN12 crossover. The baffle was exactly that fitted to the then current production Concerto. I used these for yonks, I currently have some LS50s but they aren't connected at present.
I have been using speakers with minimum cabinet-talk for decades now after noticing how much vibration there often was on cabinet walls compared to the drive units and how enormous the area of these walls is compared to the diaphragm area of the driver.
There are more and more makers concentrating on this shortcoming nowadays, thankfully.

 

[bigx5murf]

I really like the older, 1st gen Uni-Qs, I own many of them. They're usually available for pennies, because of tweeter issues, and KEF no longer offers replacements for them. But it's quite possible to repair most of them. Many of these also used 2% tolerance capacitors, so even though they're electrolytic, you don't really need to replace them despite their 20+ year age.

 

[Sal1950]

Good video, thanks for the link @amirm
Been thinking of new speakers and the LS50's are near the top of the list.
Hoping to get a listen at the Tampa show in Feb along with a few others.

 

[rebbiputzmaker]

Good video, thanks for the link @amirm
Been thinking of new speakers and the LS50's are near the top of the list.
Hoping to get a listen at the Tampa show in Feb along with a few others.

LS50s are very nice. At $1000 they are deal imo.

 

[mitchco]

I currently have a pair of LS50's for review. They are not going back...