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KEF LS50 Meta Review (Speaker)

sarumbear

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Again we talk about over or about 200Hz. Like to see how this changes the slope on a 24dB linkwitz?
I think you jumped in without reading the sub-thread. It is about using a subwoofer by itself. Most subwoofers on the market don’t work as high as 200Hz nor offer a 4th order filter.
 

BrokenEnglishGuy

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Im start to think the metamaterial is a kind of EQ but physical...., maybe that metamaterial can damper some frequencys and then not cancel others because that frequency could change the FR or if kef wanna a BBC in the FR they can do that easily too..
 
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fordiebianco

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Now that coaxial drivers seem to be back in vogue, can somebody please measure the SoundArtist SC8B? I have a pair and am quite pleased with them, but would love to see what they measure.

1628352563022.png
 

sarumbear

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maybe that metamaterial can damper some frequencys and then not cancel others because that frequency could change the FR.
Enclosure wall resonance will make no difference to the frequency response measurements.
 

sarumbear

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sarumbear

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phoenixdogfan

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First of all thank you @amirm , am really glad that you didn't punish them in your subjective review because of their bass and SPL limitations.

I own the original Anniversary model since it was released almost 8 years ago and the Meta since winter, as said from most here without sub(s) they are ideal only for nearfield listening or small rooms or low listening levels or music without much bass.

Since I have the Metas I use my old LS50 Anniversary ones for my desktop system where without a sub they go surprisingly low and that with just negative filters for room and loudspeaker correction with which they sound almost as good as my Metas:

View attachment 145942

The Metas I use for my classic stereo setup in the same not very large room and with 1,8 meters listening distance coupled to a cheap 10" subwoofer where I closed the BR port, but since those are better tuned I need and use EQ filters only up to room transition frequency of approximately 300 Hz:

View attachment 145941

Both sound really good to me, even more for the price I paid for for each pair (800€) and I have some good reference comparisons in that price range as I owned Genelec M040, Neumann KH120A and Kali IN-8 v1 in the past which I all sold as they didn't provide me significant extra qualities I need, so I preferred the for me nicer look of the LS50s and their lower vertical listening position sensitivity which is more important at my desktop system as I don't keep always the same sitting posture.

View attachment 145943
I think the smaller the room and the closer the listening position, the more important the superb vertical directivity of the LS50s (both Meta and OG) becomes.
 

phoenixdogfan

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Yeah, I know what you mean. There's the upright, focused, on the ball position and the passed-out, asleep, head on the desk, position. Good to know they sound good in both positions. ;)
Same positions as the couch, though the latter is usually the result of too many Dos Equis's and gummies.
 

MaxRockbin

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I wouldn't cross them over under 100Hz if you're using a 2nd order high pass like most people, it depends on your listening levels though. If you listen into the 90db range at your listening position you might even bump that up to 120Hz or so
But - doesn't the high crossover recommendation presume your sub (or subs) have lower distortion in that 90-120hz range than these speakers? I'm sure at some volume level that's true, but does anybody even publish distortion numbers in that range for subs? (In general the measurements for subs seem pretty minimal compared to regular speaker stats). I think the "with sub" ratings on ASR, for example, presume a perfect sub. In that case, buy two and cross them over at 20kHz.
 

David_M

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So we need a Kef R3 meta?

What would be the optimal sub crossover point for the LS50 meta?

Based on the distortion characteristics alone @96dB, I'd have a minimum 100Hz xover frequency, with 150-200Hz preferable. This means you'll need to have a wide frequency response subwoofer that has a bandwidth above 100Hz. SVS, for one, makes excellent wide bandwidth subwoofers, with excellent bass response with low distortion levels.

It'll also mean that deep or chesty male voices will emanate from the subwoofer but that's ok. This speaker is not meant to play any sort of meaningful bass undistorted bass sounds.
 

tomtoo

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I think you jumped in without reading the sub-thread. It is about using a subwoofer by itself. Most subwoofers on the market don’t work as high as 200Hz nor offer a 4th order filter.

Dont know what sub thread you talk about. I talked about this speaker in this thread. And two subwoofers as stands.
 

David_M

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I just bought them a few weeks ago as my first pair of speakers. Honestly bought Elac DBR62 and these LS50 metas at the same time and after a few days listening returned the Elacs. Kef sound was a tiny bit more robust and with a personality that I liked better. The cost difference can only be justified with aesthetics I think. I am absolutely happy with the speakers and so relieved that I see your measurements and review. Thank you. Forgot to mention that my subwoofer, svs sb2000 pro arrived a few days earlier than the speakers and they really needed that to become satisfying.

What's your xover frequency of the sb2000? Hope its at least 100Hz or more.
 

q3cpma

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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
image

https://www.audioholics.com/bookshelf-speaker-reviews/ccb-8-bookshelf/measurements

Not good. Until proven wrong, I consider that only Genelec and KEF solved the coaxial question.
 

David_M

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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.

If you are asking for subwoofer recommendations and xover frequencies, I'd choose SVS sealed subs, the SB3000, SB4000, or SB Ultra-16. You might want to get two lower-priced subs (SB2000, SB3000, SB4000) to form a killer 2.2 channel system.

I'd recommend crossover frequencies of at least 100Hz minimum (150Hz preferable), based on the measured distortion specs of the speaker.
 

fordiebianco

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Send them to @amirm and enter the queue.

Thank you for the suggestion. Unfortunately the things weigh 25kg each, making the postage to Amir from the UK prohibitely expensive. There are other members of the community who might already have a pair and the appropriate testing gear.

Nevertheless, thank you for your kind hint, would have never thought of it.
 
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