KEF LS50 thoughts

[psbfan9]

I thought the LS50s are nearfield monitors and not meant to be used as room filling, wall of sound mains.
What are the room sizes and listening distances you guys are using?
Have you tried moving the speakers to a smaller room or shortening the distance of the main listening position?
What about toe in or distance from the front and rear walls?

I don't have a horse, goat, or camel in this race but wanted to know the above.

 

[TheWarrior]

Is the algorithm (that converts Spinorama data to speaker quality score ) at least available to others so that they can try to validate the research with other speakers? I have not seen it.

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Sean Olive, I believe, would be the person to ask that. He, like Floyd, pokes his head in around here occasionally. But I think you would need to produce full Spinorama data from CTA 2034, first.

 

[Steve81]

I know Steve ... Middle aged, Maryland Steve, has wrangled a custom xo out of DM for that speaker. I wonder what he has to say and I wonder about the before and after FR of said endeavor.

MAMS... Got it.

@Steve81

I only act like I'm middle aged, I'm still in my prime

Never owned the LS50s though; the Q100s were the basis for the speakers from DM. Wasn't an XO upgrade, just harvested the UniQ driver for use in a custom 3-way.

 

[KEW]

I thought the LS50s are nearfield monitors and not meant to be used as room filling, wall of sound mains.
What are the room sizes and listening distances you guys are using?
Have you tried moving the speakers to a smaller room or shortening the distance of the main listening position?
What about toe in or distance from the front and rear walls?

I don't have a horse, goat, or camel in this race but wanted to know the above.

I don't know that they are designed to be nearfield. With the concentric drivers, they certainly are conducive to nearfield use.
I listened nearfield from 4' away. I had listened to them as "whole room" speakers earlier and had essentially the same experience. One reason I bought these for a second time was to determine if nearfield listening was a game-changer.
I did play with toe-in, and ended up at about 15-20 degrees off axis.
Walls 2 feet behind driver and around 3.5 feet to the side.
The wall behind me was over 10' away.
HTH!

 

[shkumar4963]

Sean Olive, I believe, would be the person to ask that. He, like Floyd, pokes his head in around here occasionally. But I think you would need to produce full Spinorama data from CTA 2034, first.

Not sure what you are saying. Are you saying that a researcher should do a complete Spinorama and send them to Harman to be evaluated by the company? Why not just release the method Harman used including the algorithm so that others can check the math and method and may be even duplicate results. That is how most other scientific research is done.

That may have already been done and other researchers may have already duplicated the results with other speakers. I just have not seen it and wanted to know if anyone here has seen it.

I was also looking to find out the algorithm that Harman engineers had used to convert Spinorama data for Harman speakers to speaker quality score.

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[TheWarrior]

Not sure what you are saying. Are you saying that a researcher should do a complete Spinorama and send them to Harman to be evaluated by the company? Why not just release the method Harman used including the algorithm so that others can check the math and method and may be even duplicate results. That is how most other scientific research is done.

That may have already been done and other researchers may have already duplicated the results with other speakers. I just have not seen it and wanted to know if anyone here has seen it.

I was also looking to find out the algorithm that Harman engineers had used to convert Spinorama data for Harman speakers to speaker quality score.

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I'm saying I don't know the algorithms used to predict listener preference from CTA 2034 data.

I do know that Sean Olive would be the exact person who could answer your question. You could get handed excel spreadsheets that won't do you much good without your own CTA2034 data. My point being, the exchange of information is open, but if you're just asking Sean merely for 'proof' without demonstrating your own ongoing research, he may not, have time.

 

[KEW]

I have to disagree. I would not consider that a fair analogy!

Not a fair analogy?

Exactly, your statement...

So as long as I don't look at anyone else's yard, I'll love the way you trim my hedges?

... is one I would immediately scrutinize as a BS statement (in any context). Humans have a very acute ability to sight down a line to see if it is straight, see if a curve is well-faired, or if a surface is smooth and even.
So you chose a situation where differences should be obvious to fit a situation where they are not. Thus it is an unfair analogy!
Furthermore, even though you quoted them, you seemed to miss the places (underlined below) where I pointed out I would detect problems without instant comparison:

"
It is the "night club" female vocals (Norah Jones and Emillie Claire Barlow) and the Chet Atkins tune where I believe I would still sense a difference given a 2 minute delay between listening to one speaker or the other.
Listening to the big band, now that I know to listen for the ride cymbal, I would notice, but otherwise, I doubt I would pick it out as an issue without the instant comparison. I don't think I would notice the glockenspiel differences were it not for the instant comparison. It sounded great on the KEF!

I went the trouble to accurately capture my subjective experience with these speakers at length and in specific detail. I stand by my observations as written. While you are fully entitled to your subjective opinion of these speakers (and I value that information); it is a rather futile undertaking to argue my intent against me!

Now, don't you have to go paint some walls or install some speakers?

 

[shkumar4963]

I'm saying I don't know the algorithms used to predict listener preference from CTA 2034 data.

I do know that Sean Olive would be the exact person who could answer your question. You could get handed excel spreadsheets that won't do you much good without your own CTA2034 data. My point being, the exchange of information is open, but if you're just asking Sean merely for 'proof' without demonstrating your own ongoing research, he may not, have time.

I am not questioning him or his research. I am just saying that all research is done by sharing how you came to conclusion and then letting others take it forward and test other speakers. And then publish their results.

I am not a researcher. I am just curious. And once again it may have already been disclosed and others may have already tested other speakers to show that the algorithm , math and method do work for other speakers as well.

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[TheWarrior]

Exactly, your statement...

... is one I would immediately scrutinize as a BS statement (in any context). Humans have a very acute ability to sight down a line to see if it is straight, see if a curve is well-faired, or if a surface is smooth and even.
So you chose an situation where differences should be obvious to fit a situation where they are not. Thus it is an unfair analogy!
Furthermore, even though you quoted them, you seemed to miss the places (underlined below) where I pointed out I would detect problems without instant comparison:



I went the trouble to accurately capture my subjective experience with these speakers at length and in specific detail. I stand by my observations as written. While you are fully entitled to your subjective opinion of these speakers (and I value that information); it is a rather futile undertaking to argue my intent against me!

Now, don't you have to go paint some walls or install some speakers?

Look, just because I decided at the last minute to change rooms to the master has nothing to do with the fact that we'll have to conduct the review, while in bed together...

 

[TheWarrior]

I am not questioning him or his research. I am just saying that all research is done by sharing how you came to conclusion and then letting others take it forward and test other speakers. And then publish their results.

I am not a researcher. I am just curious. And once again it may have already been disclosed and others may have already tested other speakers to show that the algorithm , math and method do work for other speakers as well.

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Not quite what you're looking for, but Floyd did a CIRMMT video on youtube that covers the history and basic methodology of the listening tests, as well as the thinking that went in to the spinorama that became a measurement standard. It's long, but it's such an extraordinary amount of information that you might watch it in chunks, anyway!

But I wasn't trying to be sarcastic when I said, if you were serious about testing, you could try to reaching out to Sean Olive - Research Fellow at Harman. He was the man responsible for most of the math, and later refined it to achieve an even higher correlation than 0.86 - partially discussed in the video.

 

[shkumar4963]

Not quite what you're looking for, but Floyd did a CIRMMT video on youtube that covers the history and basic methodology of the listening tests, as well as the thinking that went in to the spinorama that became a measurement standard. It's long, but it's such an extraordinary amount of information that you might watch it in chunks, anyway!

But I wasn't trying to be sarcastic when I said, if you were serious about testing, you could try to reaching out to Sean Olive - Research Fellow at Harman. He was the man responsible for most of the math, and later refined it to achieve an even higher correlation than 0.86 - partially discussed in the video.

Thanks. I think I have seen this video but I will see it again. But as you said, it really does not provide the necessary info. But then in a video, one does not expect to find such a thing.

But Thanks.

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[psbfan9]

Look, just because I decided at the last minute to change rooms to the master has nothing to do with the fact that we'll have to conduct the review, while in bed together...

I knew that's what 'trim my hedges' meant.

 

[PENG]

I am not questioning him or his research.

Understood, but even if you are questioning his research that would be perfectly understandable. That's why the term thesis/dessertation "defense". Findings and conclusions of research papers do not exactly equal scientific facts.

 

[TheWarrior]

Understood, but even if you are questioning his research that would be perfectly understandable. That's why the term thesis/dessertation "defense". Findings and conclusions of research papers do not exactly equal scientific facts.

I do apologize for not being equipped with the long index of Toole/Olive AES papers, but their research is incredibly comprehensive. Shkumars questions unfortunately have no simple answers.

And I do hope that you do not take it personally that I am so critical of a loudspeaker you own - I referred to you as 'sir' previously merely as a sign of respect, not sarcasm.

We don't agree on everything, but I think we both do a great job of using this forum for its intended purpose, Discussion. And I look forward to its continuance!

 

[PENG]

90% of the time I ignore subjective reviews but do read them for fun. I am quoting the two below (extracts only) just for demo. I do have reasons to trust them a little (just a little) more, but I could be wrong. Doug Schneider apparently oversees the SoundStage Newtwork (I failed to mention this by mistake, thanks to Beave who caught it)loudspeaker measurement program at the NRC and John Atkinson A has reportedly performed extensive technical analyses of well over 700 different loudspeakers.

https://www.soundstagehifi.com/index.php/equipment-reviews/557-kef-ls50-loudspeakers

The LS50’s highest frequencies sounded as if they’d been deliberately tipped up to add air and expansiveness. But violinist Vanessa-Mae’s The Original Four Seasons and the Devil’s Trill Sonata (16/44.1 FLAC, Angel), a strident-sounding recording, let me know that the LS50’s highs weren’t tipped up enough to cause it to sound objectionably bright -- any stridency I heard was inherent in the recording, not exacerbated by the tweeter. Instead, the way the LS50s’ tweeters soared through the highest frequencies of Vanessa-Mae’s recording, and of Ennio Morricone’s choral and orchestral score for the film The Mission (16/44.1 FLAC, Virgin), was on a par with what I’d heard from the R500 -- which I praised for sounding “clean, extended, and refined.”

The LS50s’ re-creation of piano was shocking -- many large speakers have trouble doing this in a way that sounds wholly natural, and most small ones don’t stand a chance

And if I had to describe in a single word the LS50s’ reproduction of Norika Ogawa’s recording of Mozart’s Piano Sonatas 10-12 (24/96 FLAC, BIS/eClassical.com), that word would be pure. Every keystroke was presented with a crystalline clarity that wasn’t only uncanny for the LS50s’ price, but for multiples of it.

The emphasis in the bass, that distinctive midrange sound that helps voices and instruments sound palpable and real, and in the highs, which to my ears seemed just a touch tipped up, pointed to a little bit of “voicing” going on -- skillful voicing.

The only real flaw I could find was this: The LS50 could play impressively loud, but when pushed too hard, the lower midrange sounded a touch chesty and resonant. This made male voices and the low end of acoustic pianos sound a bit less clear when the LS50 was played outside of its comfort zone.

The LS50’s sound, irrespective of price, was outstanding in my room: a wide-open soundfield; razor-sharp imaging; voluminous bass; soaring, clean highs; and a midband as natural as it was clear. Holy moly, this speaker sounded good -- and at a ridiculously low price.

https://www.stereophile.com/content/kef-ls50-anniversary-model-loudspeaker-page-2#Y1tJtIEpf7Ybskbr.99

the LS50's high frequencies sounded very clean, with no grain or steeliness. This is a high-quality tweeter. The LS50's treble did sound a little soft at first, compared not only with the DeVore O/96 (reviewed by Art Dudley in this issue), but also with the mellow-balanced Sony SS-AR2 (reviewed by me in October). The ostinato hi-hat cymbal in "The Trader" sounded a little subdued, though cymbals in more recent recordings, such as my own Rendezvous (CD, Stereophile STPH013-2), were reproduced with a natural tonal quality and precise, stable stereo imaging.

Pink noise revealed a slight emphasis at the top of the midrange, but this region was otherwise superbly clean and clear. The LS50's unforced transparency and lack of coloration in the mids and highs effortlessly untangled the complex vocal lines in "Measurements" from James Blake. Richard Lehnert's speaking voice in the Channel ID and Phase tracks on Editor's Choice sounded natural and free from coloration.

Classical orchestral, solo piano, and vocal recordings were better suited to the more neutrally balanced KEF, and rock to the B&W

I would go so far as to say that the LS50 is one of the finest speakers at reproducing female voices that I have heard

It is rare to find a loudspeaker that offers this combination of clarity and neutrality.

 

[PENG]

I do apologize for not being equipped with the long index of Toole/Olive AES papers, but their research is incredibly comprehensive. Shkumars questions unfortunately have no simple answers.

And I do hope that you do not take it personally that I am so critical of a loudspeaker you own - I referred to you as 'sir' previously merely as a sign of respect, not sarcasm.

We don't agree on everything, but I think we both do a great job of using this forum for its intended purpose, Discussion. And I look forward to its continuance!

No apology necessary and I trust we can continue to go back and forth respectfully in expressing our different opinions while citing/quoting relevant supporting arguments and/or facts. I do feel you tend to rely more heavily on one source (Harman), and I prefer to consider findings of multiple sources, nothing wrong with either approach, just different. I know a lot of PhDs so perhas I am too familiar with the nature of scientific research and studies.

 

[TheWarrior]

No apology necessary and I trust we can continue to go back and forth respectfully in expressing our different opinions while citing/quoting relevant supporting arguments and/or facts. I do feel you tend to rely more heavily on one source (Harman), and I prefer to consider findings of multiple sources, nothing wrong with either approach, just different. I know a lot of PhDs so perhas I am too familiar with the nature of scientific research and studies.

Thank you and I totally acknowledge what you're saying.

Like you, I've read countless reviews and AES papers that do their best to describe what and how humans hear in a variety of settings with a variety of loudspeakers, and how that should be optimized. I sold my Bose and discovered RBH.

Then I discovered Floyd, which led me to Harman's research division. The work that has been done there has allowed us to fully describe the performance of a loudspeaker, on paper. The proof of that, comes from the correlated objective measurements to the subjective preference of listener's in double blind tests. One of the beauty's of science is that this repeatable, and Harman has been doing these tests routinely for more than a decade - I just never bothered to study who else has been doing them....yet.

The problem with that science, is that it can really narrow down the number of ideal ways to reproduce sound. That does not seem to be a popular idea, but I love it for how it can ease a decision making process, which makes up half the topics on this forum. As such, I have cited Floyd when criticizing 2-way MTM center channels (which I still use) as his book produced a graph showing the cancellations and narrow dispersion that result from the design. I cited Floyd when I criticized the LS50 because he pointed me to measurements that made sense out of what I was hearing. I cite Floyd when I discuss bass and the difference in sounds above and below the transition frequency of a room. I cite Floyd when I mention his tests that prove humans have the ability to listen 'through rooms' above the transition frequency. I cite Floyd when I mention the importance of testing speakers in mono.

Yup, its repetitive, but I genuinely believe that this is information that should be shared as much as possible. Unfortunately that has me criticizing a loudspeaker that you and others have enjoyed. I hope sharing my perspective at least clarifies my intent, only to inform, not admonish. Cheers!

 

[PENG]

Yup, its repetitive, but I genuinely believe that this is information that should be shared as much as possible. Unfortunately that has me criticizing a loudspeaker that you and others have enjoyed. I hope sharing my perspective at least clarifies my intent, only to inform, not admonish. Cheers!

I do enjoyed those information and thank you very much for sharing. I like my LS50 but I like my Focals more, and see no reason to defend them on subjective basis. I do expect that many people will not prefer or like the LS50. It was only the mentioning of the 2K resonance that got me puzzled.

As Dennis mentioned, he didn't see such evidence in the Stereophile measurements. He also explained to me the NRC graphs were from far off axis, 45 degrees to 75 degrees.

He said:

All I can say is that the Stereophile measurements don't show any hint of a resonance at 2 kHz on any of the plots, including measurements taken off axis from 15 degrees to 60 degrees.

shkumar4963 also commented that:

I had a quick discussion with Dr. Toole about ls50 and NRC measurements. He thought that NRC measurements were not sufficient to predict ls50 quality.

So again, my points are on the objective side only.

 

[Alex2507]

Never owned the LS50s though; the Q100s were the basis for the speakers from DM. Wasn't an XO upgrade, just harvested the UniQ driver for use in a custom 3-way.

Holy sh!t, did I get anything right? I went sniffing around looking for the info and quickly became consumed with gear lust for gear I don't need, can't use etc. Thanks.

 

[TheWarrior]

As Dennis mentioned, he didn't see such evidence in the Stereophile measurements. He also explained to me the NRC graphs were from far off axis, 45 degrees to 75 degrees.

I looked at that thread, the specific graph of the LS50 you posted in #24 was definitely the off axis only.

But I'm not sure why anyone is disputing that a 5dB rise from 1.5khz measured across the listening window and beyond, in an anechoic chamber, would be anything but a speaker induced resonance. Even a few of Stereophile's relative dB response graphs show the 5 dB rise - the waterfalls favor resolution in the time domain.