KEF LS50 vs. Revel Performa M105

[Dr. Bob]

I'm looking for new bookshelf speakers to replace my main speakers in my music/entertainment system, and I recently auditioned these two at a high-end store near DC, so I thought I'd share my findings.

The store had a great listening room with an amp that looked like a small nuclear reactor and a CD player you could use to stun an ox. Just so you have an idea what I mean by "high end." The salesman placed the KEFS pointing straight ahead, told me to take as long as I liked, and left the room.

Some of the things I'd read online had led me to believe that the KEFs were really desktop speakers, not designed for large rooms. This is not the case. For one thing, though not as large as many bookshelf speakers, they're still pretty big: they'd leave little room on my desk for anything else. Secondly, they have plenty of sound for a normal living room. I'm not a headbanger so I never tried cranking them up to painful levels, but for reasonable listening they're more than sufficient.

The KEFs had the most stunning soundscape I've ever heard. When I played a recording of Holst's Planets symphony, I felt like I could hear where every instrument in the entire orchestra was. However, I found them a bit too bright - violins especially sounded harsh, rather than natural. This really surprised me: after all the glowing things I'd read about the LS50s the last thing I expected was tonal issues.

The salesman set up the Revels toed in toward the listening position. They were more laid back than the KEFs - the violins sounded very natural. The soundscape was good, but not quite as impressive as the KEFs. It seemed smaller and less distinct. (It only occurred to me much later that this might have had something to do with the toe-in.)

I am by no means an audiophile, and I only spent an hour or so in the store, so all this should be taken with a grain of salt. Still, I thought someone might find it helpful, and I'm curious to see what other folks' opinions are.

 

[tyhjaarpa]

LS50 is pretty amazing speaker for the price imo, and looks good as well. Havent heard Revel's so cant say anything about them. LS50 sounds pretty neutral and you can really enjoy those speakers and like you said they can fill living room with ease. I was surprised how well they play lower sounds as well even tho they are pretty small. The sound is pretty close to R500 what I have heard the LS50, missing things here and there, mostly in lows. Would of got LS50's most likely if I went to bookself way.

 

[AcuDefTechGuy]

Bias may be a factor. When you came and saw the KEF, they looked like desktop speakers or studio monitors. The KEF also look ugly to me without any grills/covers. You may have also heard other anecdotes prior to listening to them. People have seen measurements of the KEF and based their listening opinions on those measurements too.

 

[randyb]

latest stereophiles has John Atkinson comparing Revel M106 vs. LS50. Interesting read as measurements somewhat comparable but different sound...worth a read.

 

[Dr. Bob]

Thanks, Randy, that'll be really interesting to read! I didn't see it on the review page - is it print only?

 

[randyb]

Sorry for late reply. Print only for now although I think at some point ends up on web.

 

[aarons915]

I know this is an old thread but I'm currently auditioning the LS50 and agree they can be bright but I've found if you don't toe them in they sound more balanced with an even wider soundstage. People who get fatigued by bright speakers might find they like them better aiming straight out or just very slightly toed in.

 

[KenM10759]

I consider something like the Klipsch Reference R-15M to be painfully bright.

To me, the LS50 is just unusually accurate. They do sound a bit bright to me when I start listening to them because I'm so accustomed to the rolled-off a bit tweeter of my R500's. It only takes a few minutes and I'm appreciating the better highs of the LS50.

 

[Johnny2Bad]

{snip} ...
However, I found them a bit too bright - violins especially sounded harsh, rather than natural. This really surprised me: after all the glowing things I'd read about the LS50s the last thing I expected was tonal issues.
The salesman set up the Revels toed in toward the listening position. They were more laid back than the KEFs - the violins sounded very natural.
... {snip} ...

Interesting ... violins are one of the very few instruments that have fundamentals above about 1 KHz.

With regard to toe, I find loudspeakers that need no toe-in have a better overall presentation, with a bigger "sweet spot", although I don't have a problem with toe-in per se; whatever works best.

 

[Dennis Murphy]

Interesting ... violins are one of the very few instruments that have fundamentals above about 1 KHz.

1 kHz is just slightly higher than an octave above the open A string on a violin. Lots of instruments play higher than that. Clarinet, Flute, oboe, piano, trumpet, even viola (which I play), not to mention harp, triangles, cymbals, and xylophones. Most speakers run into trouble on overtones, not fundamentals, with the exception of deep bass extension.

 

[Johnny2Bad]

1 kHz is just slightly higher than an octave above the open A string on a violin. Lots of instruments play higher than that. Clarinet, Flute, oboe, piano, trumpet, even viola (which I play), not to mention harp, triangles, cymbals, and xylophones. Most speakers run into trouble on overtones, not fundamentals, with the exception of deep bass extension.

A violin bridge resonates at 1 to 4 KHz (= fundamental). Both bridge and string contribute to a violin's sonics. The range of a violin's highest string extends to just above 3500 Hz. The Upper Mid-Range is from 2.5 to 5KHz, the frequency range our ears are most sensitive to, and where a risk of brittle or harsh reproduction exists.

You were able to name a few instruments, but your list is pretty much exhaustive. Most common instruments are A 6-string electric guitar is done at about 1 KHz for fundamentals; the human male voice can't make it that far, while female vocals can't reach twice that. The Piano gets up to about the violin's top range, while only synthesizers and drums/cymbals go above them.

But the point of my post was, while listening to violins, he heard harshness or distortion, which gives us clues as to where the problem lies with the speaker's reproduction.

 

[Dennis Murphy]

A violin bridge resonates at 1 to 4 KHz (= fundamental). Both bridge and string contribute to a violin's sonics.

What's contributing to a violin's sonics is that instrument's particular overtone structure. All instruments would sound alike at a given frequency if there were no overtones. The bridge might contribute to the overtones, as does virtually every other element of the violin body, but I'm not sure what the significance of that is.

 

[Johnny2Bad]

What's contributing to a violin's sonics is that instrument's particular overtone structure. All instruments would sound alike at a given frequency if there were no overtones. The bridge might contribute to the overtones, as does virtually every other element of the violin body, but I'm not sure what the significance of that is.

Really?, I am in awe of your knowledge. Who would have thought that music contains overtones? Wow, thanks for that. You can learn something every day, I guess.

However, I specifically referred to fundamentals. Overtones are higher in frequency than fundamentals, but the fundamental is usually the loudest frequency that makes up a tone, so that if one instrument seems to reveal an issue, it's probably the fundamentals of that instrument, since they will be much higher in level than the overtones of the same instrument playing a low note, or another instrument that cannot reproduce such high frequency fundamentals.

Dragging this, screaming and kicking, back on topic, didn't you find that he found the violins to sound poorly in comparison interesting, and had you not wondered why? Or are you angry he didn't listen to any piccolos?

 

[speakerman39]

Really?, I am in awe of your knowledge. Who would have thought that music contains overtones? Wow, thanks for that. You can learn something every day, I guess.

However, I specifically referred to fundamentals. Overtones are higher in frequency than fundamentals, but the fundamental is usually the loudest frequency that makes up a tone, so that if one instrument seems to reveal an issue, it's probably the fundamentals of that instrument, since they will be much higher in level than the overtones of the same instrument playing a low note, or another instrument that cannot reproduce such high frequency fundamentals.

Dragging this, screaming and kicking, back on topic, didn't you find that he found the violins to sound poorly in comparison interesting, and had you not wondered why? Or are you angry he didn't listen to any piccolos?

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

 

[Good4it]

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

+1

 

[Dennis Murphy]

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

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.

 

[Beave]

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.

I think Dr. Bad used to be my primary care doctor.

 

[speakerman39]

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.

Dennis, I agree that he was off in his tone. Not trying to make a big deal about it, but thought that it was uncalled for. I appreciate everything you do for us here. We are lucky you are here. I have learned some things over the last few years since I been back in this hobby just by reading your posts. Your post here is a perfect example. Thanks for sharing your knowledge and/or experience with us. Many here do appreciate it!


Cheers,

Phil

 

[bboro30]

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

Well said my response to this guy would have been pretty nasty.

 

[Dennis Murphy]

Dennis, I agree that he was off in his tone. Not trying to make a big deal about it, but thought that it was uncalled for. I appreciate everything you do for us here. We are lucky you are here. I have learned some things over the last few years since I been back in this hobby just by reading your posts. Your post here is a perfect example. Thanks for sharing your knowledge and/or experience with us. Many here do appreciate it!
Cheers,

Phil

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.