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KEF LS50 Meta Review (Speaker)

sarumbear

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If i have two subs i see no reason why i should crossover at 80Hz?
Because your crossover needs to be very complicated when your high-pass filter is very near to the speaker’s f3.
 

eddantes

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With 2.1 channel system, how do you guy separate a low frequency to sub? Kindly name the hardware thank you.

Many Parasound products have both Low and High pass settings.

1628345260890.png
 

Tangband

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Because your crossover needs to be very complicated when your high-pass filter is very near to the speaker’s f3.

Thats true.
Well, if one plugs the Kefs ( closed box ) its gonna fall about 12 dB/oct beyond the speakers resonance frequence.
If you then invert the Kefs, you have a pure acoustical filter for the main speakers , that can be combined with a non-inverted filter for the subwoofer at 12 dB/oct LP filter.

A much more optimal solution would be :

1.Plug the Kefs so they are closed box.
2.Use two subwoofers in stereo.
3.Use an external LP/HP dsp filter, such as minidsp or similar.
4.Crossover at 110Hz , with 6:th order filter ( 36 dB/oct ) electrical , both LP and HP filter.

NHT did just that in their NHT xd-system with digital crossovers, with great success. Read more here:
https://www.stereophile.com/content/nht-xd-active-loudspeaker-system-measurements
 
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sarumbear

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Thats true.
Well, if one plugs the Kefs ( closed box ) its gonna fall about 12 dB/oct beyond the speakers resonance frequence.
If you then invert the Kefs, you have a pure acoustical filter for the main speakers , that can be combined with a non-inverted filter for the subwoofer at 12 dB/oct LP filter.
Then you will not have the expected benefit from the sub. You will still have the same distortion limited level. Not to mention if you can achieve a Q of 0.7 when the port is blocked.
 

tomtoo

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Because your crossover needs to be very complicated when your high-pass filter is very near to the speaker’s f3.

But we talk about higher xover point not lower. So explain again pls?
We talk about two subs, and there is just no reasoning to cross them that low.
 
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Tangband

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Then you will not have the expected benefit from the sub. You will still have the same distortion limited level. Not to mention if you can achieve a Q of 0.7 when the port is blocked.
Thats true, and thats why I had a better suggestion with an external dsp filter.;)

Using inverted mains without any filtering and plugged, combined with subwoofers with 12 dB/oct subwoofer filtering is an approach that Rel acoustic uses. It can work rather good soundwise, if the mains can take the extended conetravel.
 
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groovybassist

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I have the LS50 Meta and run them with a Neurochrome Modulus-286 in my main living space, which is a large-ish open concept. I listen at low-to-moderate volume and am often surprised at how much bass they actually have, and how well they fill the space. I’ve had too many pairs of speakers over 35+ years in this hobby and I can honestly say my current system (LS50 Meta, Neurochrome Modulus-286, Matrix Audio Element X) has fooled me into thinking sounds are real/in the room more than all of my other systems combined! I was very much on the subjective side of the fence for most of my audiophile life, but as you can see from my current system, I’ve seen the light in how important properly engineered, high performance components are to the listening experience.
 

sarumbear

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But we talk about higher xover point not lower. So explain again pls?
If the crossover frequency is within an octave or less than the speaker’s f3 the resulting slope of the high pass filter will not have the expected slope. You can compensate that using Linkwitz Transformation but thats complicated.
 

sarumbear

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Thats true, and thats why I had a better suggestion with an external dsp filter.;)
Not originally, hence my initial response :)
 

tomtoo

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If the crossover frequency is within an octave or less than the speaker’s f3 the resulting slope of the high pass filter will not have the expected slope. You can compensate that using Linkwitz Transformation but thats complicated.

Again we talk about over or about 200Hz. Like to see how this changes the slope on a 24dB linkwitz?
 

YSC

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does the genelec 7040 solution also do high-pass filter for the signal going forward to speakers later, so giving a real crossover situation?
yes they did, so pairing with the genelec monitors is basically plug and play, with the dip switches basicalaly fixed all those room issues
 

Aperiodic

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Conclusions
KEF moves the bar it set with the LS50 with the Meta revision. I was not a fan of the original but they have won me over with near perfect measurements and listening test results. Make this speaker handle more dynamics in bass and I would kiss the ground it walks on. But that is not there so a notch lower for me. But really, this is an excellent speaker. No doubt about that.

I am happy to recommend the KEF LS50 Meta. Suggest pairing it with a subwoofer if you want to play loud bass though.

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Yep. Sounds like it would be a worldbeater with a sub and a highpass on the midwoofer.

Measurements I have seen on coaxial drivers seem to bear out the claims of improved imaging and dispersion behavior. Can someone get a pair of
Hsu Research CCB-8 coaxials into Amir's lab so we can find out if it is the budget behemoth some say it is? Prices start at a dirt-cheap-in-today's-audio-world $699 a pair (shipping additional). Note, they also rate the sensitivity at 94dB (!), amazing for a moderate-sized bookshelf; if this is remotely accurate, you wouldn't need a monster amp to drive it. Only reviews seem to be from 'My Opinion' type websites though.
https://hsuresearch.com/products/ccb-8.html
 
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FeddyLost

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If we look at distortion graph, it's obvious that for something resemblin midfield listening one need to cross around 200 Hz.
Not much subwoofers really suitable for that, and something like Rythmik FM8 (or maybe L22) is not an ordinary product.
It's not the Genelec W371 case, it will require some effort from user.
I think Kef still need to sell their R series floorstanders and will not offer any complementary bass units for LS50 keeping them exclusively nearfield...
 

Frgirard

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A subwoofer with an external crossover can be cut at 200Hz.You need a sub available from a line input by passing the internal cross over. Neumann kh805 by example.
Without external crossover The flexbase25 by amphion can be cut until 260 Hz.
 
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