KEF LS50 vs. Revel Performa M105

speakerman39

speakerman39

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#21
I appreciate the post--I certainly wasn't criticizing you. The whole discussion has been academic and of no great importance. If there's anything useful to be learned, it's that virtually all of the frequencies that lie at and above 2 kHz on a frequency response chart represent overtones (with the exception of the upper octave of a piano, and some triangle and flute-piccolo material). That's why a speaker that sounds off in the midrange may seem to measure well in the area that we generally regard as the midrange--it's the upper harmonics that aren't being reproduced correctly. And this also means that virtually all of the sound you hear coming out of most tweeters consists of overtones.
Interesting Dennis. I did not know that. Learn something new every single day. Today is no different in that regard. Thanks so much for the info! :):):)


Cheers,

Phil
 
P

PENG

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#22
His reply is probably off in tone, but mainly I just find his comments confusing. As I understand it, the LS50 has been criticized for having an off-axis resonance centered in the lower highs. That could indeed affect the presentation of violins, but not because "violins are one of the very few instruments that have fundamentals above about 1 KHz." As I pointed out, that simply isn't true. Many other instruments would suffer because they spend a good bit of time reproducing fundamentals above 1 kHz. If violins do sound particularly problematic on the KEF's (and I have no first-hand experience that would confirm this),then the problem is more complex and involves the interplay of the speaker's reproduction of violin fundamentals and the associated overtones, which give the instrument its characteristic sound. (And since I have been playing violin seriously for over 60 years, I also know that a violin bridge's first vibration mode is the same as the vibrating string. If you shake any structure, it's fundamental vibration mode will be at the same frequency as the force that's shaking it. It won't produce a fundamental of 4 kHz if the string is vibrating at 1 kHz. ) Finally--yes I am interested in why Dr. Bad singled out violins as faring particularly poorly on the Kef's. I've been designing speakers for over 20 years and am always interested in tracing down the cause of loudspeaker colorations and assorted ills. It's hard to correct or avoid a problem if you don't understand its cause.
Violins sound fine to me on my LS50s, and I know quite well how a violin should sound. In fact, one reason I bought the LS50 is that their violin sound do sound similar to the $32,000 Blades, not an AB comparison though and the Blades were powered by 2X1kW Mc amps when I auditioned them.

Where can I find the information about the LS50's off axis resonance at 2 kHz, with back up measurements?
 
D

Dennis Murphy

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#23
Violins sound fine to me on my LS50s, and I know quite well how a violin should sound. In fact, one reason I bought the LS50 is that their violin sound do sound similar to the $32,000 Blades, not an AB comparison though and the Blades were powered by 2X1kW Mc amps when I auditioned them.

Where can I find the information about the LS50's off axis resonance at 2 kHz, with back up measurements?
The measurements are here: https://www.soundstage.com/index.ph...&catid=77:loudspeaker-measurements&Itemid=153
 
P

PENG

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#24
Thank you, so you do consider the 2K Hz peak excessive? No review available for the Blade I compared the violin with, but the $25,000 Blade 2 does seem to have similar response, relatively speaking. The also much more expensive $7,700 Magico doesn't look better either.

Loudspeaker curves are so ugly compared to amplifier's.


LS50



Blade 2





Magico S1 MkII

 
D

Dennis Murphy

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#25
This is getting a little complicated. The graphs you're comparing are the far off-axis plots that begin at 45 degrees off axis and continue to 60 degrees and then to 75 degrees. The plot for the KEF that was being discussed is the on-axis, 15 degrees off, and then 30 degrees. It shows a peak starting to develop at 15 degrees. The far-off axis plots are designed to show problems that arise due to differences in the dispersion patterns of the drivers. The various dips and elevated portions may not be due to inherent irregularities in the individual drivers or diffraction effects, but rather to differences in dispersion breath of adjacent drivers at extreme angles. If you look at the "listening window" plot for the Blade, it's flat as a pancake. That's the averaged response + and - 15 degrees horizontally and vertically.
 
P

PENG

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#26
This is getting a little complicated. The graphs you're comparing are the far off-axis plots that begin at 45 degrees off axis and continue to 60 degrees and then to 75 degrees. The plot for the KEF that was being discussed is the on-axis, 15 degrees off, and then 30 degrees. It shows a peak starting to develop at 15 degrees. The far-off axis plots are designed to show problems that arise due to differences in the dispersion patterns of the drivers. The various dips and elevated portions may not be due to inherent irregularities in the individual drivers or diffraction effects, but rather to differences in dispersion breath of adjacent drivers at extreme angles. If you look at the "listening window" plot for the Blade, it's flat as a pancake. That's the averaged response + and - 15 degrees horizontally and vertically.
Thank you for the explanation. So would you say the LS50 is bad though? I didn't read JA's raving review (Stereophile) until well after I purchased and enjoyed mine, but couldn't help wondering why he didn't seem to think his measurements on the LS50s were less than good.
 
D

Dennis Murphy

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#27
Thank you for the explanation. So would you say the LS50 is bad though? I didn't read JA's raving review (Stereophile) until well after I purchased and enjoyed mine, but couldn't help wondering why he didn't seem to think his measurements on the LS50s were less than good.
I've never heard the LS-50, and if I had I wouldn't venture an opinion since I sell speakers that are in direct competition. 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. The NRC measurements have higher resolution since they're taken in a real anechoic chamber, but I've had one of my speakers measured there, and aside from a few more tiny wiggles, the NRC measurements matched the ones I took using the same technology John uses for Stereophile. So I dunno. If they sound good to you, they are good.
 
Johnny2Bad

Johnny2Bad

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#28
Johnny, after reading your post just know it comes across as being a bit condescending. You know, Dennis is a very highly regarded and respected member of this forum, as well as, plenty of others out there. I know I would, and other forum members here as well, would appreciate it a lot if you showed Dennis a little more respect. Not trying to be a smart-a$$ here myself, but Dennis really is a good guy and is quite knowledgeable. Just saying...........


Cheers,

Phil
Yeah, I was in an unusually bitchy mood. But I honestly thought it was pedantic and somewhat off topic to point out what anyone with basic music education knows ... I dunno, doesn't everyone take music classes in public school in America? It's part of the curriculum here (Canada),you have to take it in the ninth grade.

Apologies to Dennis, if you were offended, by the tone of my post, which is a bad pun but is also a clumsy attempt at levity. Nothing personal intended.
 
speakerman39

speakerman39

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#29
Yeah, I was in an unusually bitchy mood. But I honestly thought it was pedantic and somewhat off topic to point out what anyone with basic music education knows ... I dunno, doesn't everyone take music classes in public school in America? It's part of the curriculum here (Canada),you have to take it in the ninth grade.

Apologies to Dennis, if you were offended, by the tone of my post, which is a bad pun but is also a clumsy attempt at levity. Nothing personal intended.
No worries Johnny. We all have those days. Was not trying to make a big deal about it. Just thought it was a bit off kilter if you will. Actually, I have enjoyed reading your posts and have learned a few things here and there. Hope that you continue to hang out with us. Have a good night! :):):)


Cheers,

Phil
 
D

Dennis Murphy

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#31
That would be no! It is not part of the curriculum. It was an elective which can be chosen at my daughter's high school.
Right--I sincerely doubt that public school children, or private school for that matter, are learning about fundamentals vs. overtones. And if they are, I want to find out where so I can make a donation. But I suspect 2bad was kidding.
 
Y

yepimonfire

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#32
Personally, i found the ls50s sounded colored, and if accuracy is the intended goal, would not purchase then myself.

Sent from my LM-X210(G) using Tapatalk
 
P

PENG

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#33
No worries Johnny. We all have those days. Was not trying to make a big deal about it. Just thought it was a bit off kilter if you will. Actually, I have enjoyed reading your posts and have learned a few things here and there. Hope that you continue to hang out with us. Have a good night! :):):)


Cheers,

Phil
You are being very generous.:)
 
Alex2507

Alex2507

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#34
You are being very generous.:)
It's a kinder, gentler place we're running here. :D

This might be the first time in history that a Canadian was rude to an American first. War council is in chambers. Consider yourselves warned. Prepare for attack. o_O
 
P

PENG

Audioholic Overlord
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#35
Personally, i found the ls50s sounded colored, and if accuracy is the intended goal, would not purchase then myself.

Sent from my LM-X210(G) using Tapatalk
Even just going by the NRC, or Stereophile's measurements it should be obvious that most if not all loudspeakers should be considered colored. Just compare their frequency response and THD vs amplifiers you can see the huge difference. By all available measurements, therefore objectively speaking the LS50s are actually more on the accurate side of the spectrum, but relatively speaker of course.

On the subjective side, all bets are off. To you the LS50 could in fact sounded colored, and I assume you meant compared to the speakers you own or prefer. Yet, even JA, who took most if not all the Stereophile measurements, seem to like the LS50 so much that the magazine included it in the class A group. I don't suppose JA is the highly subjective type who would rank a speaker so high even unless he considers them "accurate" enough in relative term. Just my 2 cents..that even if accuracy is the intended goal, the LS50 should be considered, for near field applications.
 
P

PENG

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#36
It's a kinder, gentler place we're running here. :D

This might be the first time in history that a Canadian was rude to an American first. War council is in chambers. Consider yourselves warned. Prepare for attack. o_O
Agree, that's why I gave a like rating. It's not Johnny's first time, and I consider my responses similarly gentle too each and every time. I respect the fact that when called out, if convinced, he would do the right thing.
 
Johnny2Bad

Johnny2Bad

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#37
Right--I sincerely doubt that public school children, or private school for that matter, are learning about fundamentals vs. overtones. And if they are, I want to find out where so I can make a donation. But I suspect 2bad was kidding.
Actually, no, it really is part of the non-elective curriculum for 9th Grade here. Although just like in the US Education is Provincial Jurisdiction, so might be different elsewhere.

It's essentially a "music appreciation" class, not for musicians specifically, but it covers the math relationship, tone relationship of instruments, song composition, lyrics as modern poetry, musical genres, that kind of thing. For playing instruments you would take "Band" which is an elective, although I seem to recall having recorders (the instrument) being passed around at some point. It was an easy class, fun even.

Very few private schools in Canada, especially K-12; a few military ones. But we also fund alternate schools via Education Taxes (part of your Property Tax assessment); you denote what school system you want to support when you pay those, although if you don't denote one, it will default to the Public system.

The significance of that is, the taxpayer and whether you have any children in any given system are not tied together; you support a system and that's that. However the tax rate will be set by the School Board you support, so your Property Taxes will vary based on that. In practice there isn't much difference, a few %, but that's how it's administered.

Everybody takes a standard curriculum and then the school can teach it's unique classes, some of which count as credit since some electives are required to pass a grade. Seven full class credits are mandatory to complete a grade, most students will take eight, there is barely room for nine but you can do it if you're a keener.*

Mostly alternate language schools (you can take French, Cree or Ukrainian immersion here, no English instruction after the third grade, K-8) and religious schools (Catholic, which is huge, about 35% of students overall, K-12),Mennonite (K-8),not sure about which others.

There is a lot of leeway with regard to electives a school can teach, as long as you are learning *something* the Province will probably allow at least a half credit. At my HS we had a work experience class for 11 & 12, half credit, friday afternoons. You could make an arrangement with almost any business that could teach a skill, go there on your friday afternoon, get a half credit.

* Two English, one Math, one Science, History and PhysEd are mandatory (5 credits; no credit for PhysEd, which was a simple Pass/Fail and some had medical waivers. You failed PhysEd by not showing up for class, which you can't get away with for long anyway, unless you decided to do a year's worth of detention instead). A second Math, two more Sciences plus various electives fill out the minimum 7 credit load. I took everything except Biology and had French and Shop (mostly woodworking) as electives (9 credits).

In College when I went a second language was still mandatory to graduate, not required anymore. I had to take the "hard" French class because i took it in HS, one of those things where if I knew better, I wouldn't have bothered with HS French and just took the equivalent in University.

Later on in my rookie year when it was too late to change, I met a guy, he was the drummer from Sweeny Todd ("Roxy Roller"),we became buddys and he was taking Mandarin Chinese. Hot Tip: world's easiest college credit aside from basket weaving; all he did was look up characters in a book and wrote them down. Even the Prof mostly just looked up characters in a book and wrote them on a projector. Open book exams. D'oh!
 
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Johnny2Bad

Johnny2Bad

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#38
Violins sound fine to me on my LS50s, and I know quite well how a violin should sound. In fact, one reason I bought the LS50 is that their violin sound do sound similar to the $32,000 Blades, not an AB comparison though and the Blades were powered by 2X1kW Mc amps when I auditioned them.

Where can I find the information about the LS50's off axis resonance at 2 kHz, with back up measurements?
John Atkinson does a fairly comprehensive measurement of the LS-50's (and I believe the Revels as well) in Stereophile also. Just search on their website, not sure if it's online though.
 
speakerman39

speakerman39

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#39
You are being very generous.:)
Peng, after all of the times you had my run and re-run Audyssey I guess it has had a softening effect.......LOL!!!! :p:eek::p Not to mention as we get older I think that we all mellow out some. Sure seems like that to me.


Cheers,

Phil
 
P

PENG

Audioholic Overlord
Ratings
5,552 9 1
#40
John Atkinson does a fairly comprehensive measurement of the LS-50's (and I believe the Revels as well) in Stereophile also. Just search on their website, not sure if it's online though.
It was published, and I read that review twice, JA didn't say anything about any such problematic resonance. He seemed to love the LS50.
 

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