KEF LS50

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My experience with the KEF LS50 and conclusions after 3 weeks of ownership before I returned them.

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They look great and came packaged quite well. I use all SS gear, set up on sand filled 36" stands in my great room area approximately 24' by 30'. ...

I bolded the setup problems. Use them in an appropriate sized room at the correct stand height for correct conclusions.
 
Another teaser... LS50 drivers, raw measurements on and 30 degrees off axis:

Кеф ЛС50 нискотон&.png

Кеф ЛС50 високото&.png
 
Yup

On axis and roughly 30 deg off axis. Calibrated Behringer ECM8000, M-audio FastTrack USB, Holmimpulse. Gate is good to about 85-90Hz.

Measurement conditions


https://i.postimg.cc/B68BsJQX/IMG-2671.jpg

Midwoofer and tweeter


https://i.postimg.cc/gkbHFF92/50-a.png


https://i.postimg.cc/1RqrjRjd/50.png

Simulation of Kef's factory crossover> frequency, impedance and phase response


https://i.postimg.cc/yxchgnRK/LS50.png


https://i.postimg.cc/QtRkdvHS/LS50.png


https://i.postimg.cc/QNyvpMWn/50.png

Other LS50 measurements for comparison
https://www.stereophile.com/content/kef-ls50-anniversary-model-loudspeaker-measurements
https://www.soundstagenetwork.com/i...&catid=77:loudspeaker-measurements&Itemid=153

Playing with it for an hour: on axis and 30 deg off axis


https://i.postimg.cc/RVmp1nZd/50.png


https://i.postimg.cc/JnqD9gjG/50.png
 
@StellarElephant:

Here's factory crossover: https://www.diyaudio.com/forums/att...86d1543159536-kef-ls50-crossover-img_8163-png

Mine is quite different because i'm still trying to get it right by my standards. It evolved into something like this, and it will keep evolving until i'm satisfied i guess:

ПРОБНА СКРЕТНИ&#10.png

Now, i'm sure that guys at Kef could do much better job if they wanted to, but we diyers must manage with limited resources that we have - no anechoic rooms, no expensive software, no knowledge gathered from years of research in papers, some of it weren't even published.

Bottom line, i'm grateful they (Jack Oclee-Brown especially) engineered drivers this good because it is a great base for some serious diy playing :)

@Matty: My friend is working on Q100. He revised cabinet and crossover and from measurements i've seen - it measures better than anything i've seen so far at any price point. It's a bold statement but when you see that flat frequency response and that off axis behavior, you must stand in awe of Kef's achievements joined with tireless effort of a diyer enthusiast. In redesigned cabinet (large roundovers and port to the back), Q100 driver easily measures better than LS50 driver in factory cabinet. He will publish it eventually so be patient.
 
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I was looking for a comparison of the KEF LS50 to the Q150 and found this. Does the LS50 sound better than the Q150? The spec on the Q150 look better on paper (screen) than the more expensive LS50. The cabinet of the LS50 does look better, but not $600 better (on top of the smaller freq response and less sensitivity)!

On one of the KEF's photo shows the Q150 on bookshelf but I didn't think rear ported speakers did well shoved in shelf like that...

Out of curiosity, does anyone know how the manufacturer comes up the minimum recommend power needed? They say only 10 watts for a 86dB speaker! The Martin Logan Motion 15 state a min of 20 watts for their 96dB speakers.
 
When I first heard my KEF Q100 had no bass, I was about to return them. They needed about two hundred hours until the sound stopped improving. I guess the coaxial suspension is very rigid at first.

BTW, I have made a new audiophile capacitor bypass. Now with MiFlex KPCU-01 0.022 uF 600Vdc.

Audiocircle: Looking for a new pair of 0.22uf coupling caps.

An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.
 
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