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KEF LSX Review (Wireless Speaker)

mfgillia

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Which do you think sound better? I found the LSX to sound better in some instances, which was surprising ( albeit in a 12m sq room )
For nearfield on a desk I prefer the LSX though I know many who prefer the larger system due to deeper bass.

For a 12 sqm room the LSX does sound better and fuller than a system it's size should but I prefer the LS50w for the larger woofer and ability to serve double duty in a 5.1 surround system.
 

Xyrium

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I debated the powered KEF's or the Gennie 8030s, though the 8030s seemed to be more promising at the time (two years ago), so I went with them. I must also add that the grilles on the 8030's have saved their drivers from my, then, 5 year old many times since their purchase. :)

Still, KEF is doing good things with these, me likey. Thanks to you, and the member who sent them in Amir.
 

mononoaware

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I must also add that the grilles on the 8030's have saved their drivers from my, then, 5 year old many times since their purchase. :)

I have seen a few photos in “google image search” of KEF LS50 customers making and applying their own DIY grilles. . .
They look absolutely horrid. . .

I forgot the search term I used, so I found them artificially this time but. . .

Prepare yourself. . .

img_20170409_201827-jpg.847737


img_20170318_162150-jpg.847738
 
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Kachda

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I have seen a few photos in “google image search” of KEF LS50 customers making and applying their own DIY grilles. . .
They look absolutely horrid. . .

I forgot the search term I used, so I found them artificially this time but. . .

Prepare yourself. . .

img_20170409_201827-jpg.847737


img_20170318_162150-jpg.847738
this looks like a mess with diffractions due to the thick frames.

better to buy some acoustically transparent cloth and wrap the front face. won't provide any physical protection but may prevent kids from poking the tweeter.
 

mononoaware

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this looks like a mess with diffractions due to the thick frames.

better to buy some acoustically transparent cloth and wrap the front face. won't provide any physical protection but may prevent kids from poking the tweeter.

I am sure whomever tried this thought of the possibilities. . .
Maybe “cloth” did not provide enough protection and had trouble staying fixed in place.
There was one more image I did not include which showed before with four globs of adhesive glue surrounding the UniQ driver. . . I think the image is a bit too graphic in nature. . .
 

wwenze

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With a smoothed graph and in-room response the flawed FR doesn't look too bad compared to SC203

1626881919468.png
 

o2so

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Thank you Amir for this review. I am using the lsxs on a desktop set up for very near-field listening (about 0.7m), with a kc62 crossed over at 100 Hz.
I have had these speakers just for a few weeks now but I am struggling to measure them properly. I am getting quite variable and unpredictable (at least, by me) frequency response above 7-8k. Some sweeps look ok, some come up with a dip, some come up with a bump. There could be small differences in the position of the mic, and there is me holding the mic just behind it. Could this be due to random reflections/comb-filtering due to me being there and the big computer screen, 50cm in front of me, in between the speakers?

1629844936269.png
 

preload

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Thank you Amir for this review. I am using the lsxs on a desktop set up for very near-field listening (about 0.7m), with a kc62 crossed over at 100 Hz.
I have had these speakers just for a few weeks now but I am struggling to measure them properly. I am getting quite variable and unpredictable (at least, by me) frequency response above 7-8k. Some sweeps look ok, some come up with a dip, some come up with a bump. There could be small differences in the position of the mic, and there is me holding the mic just behind it. Could this be due to random reflections/comb-filtering due to me being there and the big computer screen, 50cm in front of me, in between the speakers?

View attachment 149337

Did you take mono measurements using the MMM technique? That method should be reproducible with relatively tight reproducibility. Also, the LSX HF response drops off pretty fast, particularly off-axis, so make sure you're staying consistently on axis with your mic.
 

Ata

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Thank you Amir for this review. I am using the lsxs on a desktop set up for very near-field listening (about 0.7m), with a kc62 crossed over at 100 Hz.
I have had these speakers just for a few weeks now but I am struggling to measure them properly. I am getting quite variable and unpredictable (at least, by me) frequency response above 7-8k. Some sweeps look ok, some come up with a dip, some come up with a bump. There could be small differences in the position of the mic, and there is me holding the mic just behind it. Could this be due to random reflections/comb-filtering due to me being there and the big computer screen, 50cm in front of me, in between the speakers?

View attachment 149337

It is puzzling, but I think the most likely explanation is indeed minor movements of the mic from one measurement to the next. Using the MMM RTA technique is going to help with that.

A minimum phase or group delay graph would be useful to figure what is going on around 450 and 900 Hz, these are narrow but very steep and deep, and could be audible.
 

milosz

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Some of that curve looks to me to be reflection artifact- a repeating pattern is usually a telltale sign of reflection artifact.

There's a reason that measurements of speakers attempt to emulate an anechoic response - if the speaker has a good anechoic response, it's a good starting point for using it to reproduce sound. Yes, it will interact with the environment, but that's inevitable. If the speaker starts out with an even amplitude response to begin with, the chances are good that it will sound good in use. Our brain-based hearing mechanism can hear "room sound" and can compensate for this while listening, to some degree. This seems to be true unless there are really strong room effects. The room situation is always going to place it's imprint upon the sound, the only way around that is to use headphones. Room treatments can deal with some problems to some degree, and electronic room correction can as well- to a degree- especially in terms of amplitude response. But time domain problems - ringing, delays from bad reflections, etc- these are hard or impossible to correct.
 
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o2so

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Some of that curve looks to me to be reflection artifact- a repeating pattern is usually a telltale sign of reflection artifact.

There's a reason that measurements of speakers attempt to emulate an anechoic response - if the speaker has a good anechoic response, it's a good starting point for using it to reproduce sound. Yes, it will interact with the environment, but that's inevitable. If the speaker starts out with an even amplitude response to begin with, the chances are good that it will sound good in use. Our brain-based hearing mechanism can hear "room sound" and can compensate for this while listening, to some degree. This seems to be true unless there are really strong room effects. The room situation is always going to place it's imprint upon the sound, the only way around that is to use headphones. Room treatments can deal with some problems to some degree, and electronic room correction can as well- to a degree- especially in terms of amplitude response. But time domain problems - ringing, delays from bad reflections, etc- these are hard or impossible to correct.
its probably me being there, I should have stepped away from the mic. Side walls are very far away
 

o2so

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I did some testing. The variability of measurements around 10k Hz was simply due to being too much off-axis and was fixed by pointing the speakers straight to my ears. Fair enough, we are talking 8 to 10k Hz.
Most of the oscillations throughout the mid-band became much smaller after I threw a towel on my desk, so these are likely desk reflections.
After changing the orientation of the speakers, measurements were consistent and it was easy enough to eq via REW. Very happy with the result, see below the measured response (blue = before EQ, green = target, red = after EQ). Distortion is also quite good, the KC62 does very well for its size.

1629877111903.png


1629876963570.png
 
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phoenixsong

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I did some testing. The variability of measurements around 10k Hz was simply due to being too much off-axis and was fixed by pointing the speakers straight to my ears. Fair enough, we are talking 8 to 10k Hz.
Most of the oscillations throughout the mid-band became much smaller after I threw a towel on my desk, so these are likely desk reflections.
After changing the orientation of the speakers, measurements were consistent and it was easy enough to eq via REW. Very happy with the result, see below the measured response (blue = before EQ, green = target, red = after EQ). Distortion is also quite good, the KC62 does very well for its size.

View attachment 149401

View attachment 149399
Interesting how even simple towels have a notable effect- might play around with them sometime
 
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