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Kef R3 Bookshelf Speaker Review (Erin's Audio Corner)

Zvu

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What you see there is the evidence of choices made with respect to enclosure size and port tuning frequency.....

I'm not so sure about that. Here is the crossover for Kef R3* woofer, blue is with filter, black without. Crossover frequency is about 450Hz:

Кеф Р300 нискотонац.png

Here is without the RLC filter:

Кеф Р300 нискотонац без филтера.png

If we would make it further away from 450Hz (around 1000Hz, not saying it's a good idea but for test purposes) even without RLC we'd get this:

Кеф Р300 нискотонац укрштање 1000 херца.png

So slope has more to do with crossover (namely, coil in series) than with bass tuning and also you can't do much about that 120Hz hump by changing port tuning or cabinet size.

* This is actually R300 woofer but differences with R3 are quite small regarding the subject.
 
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Descartes

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When the 80hz crossover really took off, it was because it was IIRC a couple octaves below what the best test subjects could localize when they were hammering out the THX standard. Which is to say that a steeper slope then 4th order or two subs co-located would let you go higher then 80hz with little to no chance of localization.

Interesting any publications on this? Does that mean that with two subs or more one can increase the cross over to 150Hz?
 

aarons915

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So should the KEF LS50 be crossed over at 150Hz then?

If you look at the distortion of the LS50 it really starts rising below 200Hz but it's still at about 3% at 150Hz so 150Hz would basically let you play them as loud as you want but I don't necessarily think you need to go that high. A 120Hz 2nd order high pass still keeps them below 3% distortion, which shouldn't be audible. There are a few studies on sub localization and basically 2 subs are better than 1 when they're up front but generally 120-140Hz is about the highest you can go before localization becomes easier. I think this is highly dependent on your setup though, people who like a rising bass response (house curve) probably need a lower crossover point since the bass levels are higher than your mains.


No. I nailed it down to the 2.5-3kHz region.

I think you mentioned this in the youtube review but just wanted to confirm, did you figure this out by listening to pink noise at certain frequency ranges to see where it sounded harsh or some other means? It took me awhile because I was testing out different PEQ filters so a faster method would be nice in the future.
 

Descartes

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So what is the optimal cross over point for the LS50?

And yes I am familiar with the following:

“Optimal Configurations for Subwoofers in Rooms Considering Seat to Seat Variation and Low Frequency Efficiency”
Todd Welti
Harman International Industries
 

sigbergaudio

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Interesting any publications on this? Does that mean that with two subs or more one can increase the cross over to 150Hz?

Even with only one subwoofer, if you have it on the front wall and within the triangle of you and the speakers, you're probably good at 100-120hz.
If you have two located symmetrically (one at each speaker) you can cross over as high as you like.
 

Digi

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Note: I put my site in the title so this thread wouldn't get confused with Amir's test which can be found here:
https://www.audiosciencereview.com/forum/index.php?threads/kef-r3-speaker-review.12021/
Also, to get ahead of things, to address one difference between Amir's and my data: I modified my microphone boom to eliminate reflections from the mic holder which otherwise results in comb filtering above 2kHz. Discussed here.

Okay, here we go.

My full writeup can be found on my site here:
https://www.erinsaudiocorner.com/loudspeakers/kef_r3/




Kef R3 Bookshelf Speaker Review
  • Sunday, Mar 14, 2021
DSC09585.JPG

Foreword / YouTube Video Review
The review on this website is a brief overview and summary of the objective performance of this speaker. It is not intended to be a deep dive. Moreso, this is information for those who prefer “just the facts” and prefer to have the data without the filler.



However, for those who want more - a detailed explanation of the objective performance, and my subjective evaluation (what I heard, what I liked, etc) - please watch the below video where I go more in-depth.



Information and Photos

I have provided an introduction to this speaker on my YouTube channel and provided below.


The Kef R3 is 3-way compact bookshelf speaker. It features a 6.5-inch midwoofer and a 5-inch concentric “Uni-Q” midrange/tweeter. The R3 features a rear port and currently comes in three colors: gloss black, gloss white, and Walnut. The R3 comes with a removable grille as well.
Price per pair is approximately $2000 USD.

DSC09601.JPG


DSC09603.JPG


DSC09606.JPG


DSC09586.JPG










CTA-2034 (SPINORAMA) and Accompanying Data
All data collected using Klippel’s Near-Field Scanner. The Near-Field-Scanner 3D (NFS) offers a fully automated acoustic measurement of direct sound radiated from the source under test. The radiated sound is determined in any desired distance and angle in the 3D space outside the scanning surface. Directivity, sound power, SPL response and many more key figures are obtained for any kind of loudspeaker and audio system in near field applications (e.g. studio monitors, mobile devices) as well as far field applications (e.g. professional audio systems). Utilizing a minimum of measurement points, a comprehensive data set is generated containing the loudspeaker’s high resolution, free field sound radiation in the near and far field.

For a detailed explanation of how the NFS works and the science behind it, please watch the below discussion with designer Christian Bellmann:

A picture of the setup in my garage:
vlcsnap-2021-03-13-15h53m34s929.png

The reference plane in this test is at the tweeter/midrange. The speaker was tested in ported configuration (the port was not sealed). All testing in this review was done without grille.

Measurements are provided in a format in accordance with the Standard Method of Measurement for In-Home Loudspeakers (ANSI/CTA-2034-A R-2020). For more information, please see this link.

CTA-2034 / SPINORAMA:
Kef%20R3%20CEA2034.png


Early Reflections Breakout:
Early%20Reflections.png


Estimated In-Room Response:
Estimated%20In-Room%20Response.png


Horizontal Frequency Response (0° to ±90°):
SPL%20Horizontal.png


Vertical Frequency Response (0° to ±40°):
SPL%20Vertical.png


Horizontal Contour Plot (not normalized):
Kef%20R3%20Horizontal%20Contour%20Plot%20%28not%20normalized%29.png


Horizontal Contour Plot (normalized):
Kef%20R3%20Horizontal%20Contour%20Plot%20%28normalized%29.png


Vertical Contour Plot (not normalized):
Kef%20R3%20Vertical%20Contour%20Plot%20%28not%20normalized%29.png


Vertical Contour Plot (normalized):
Kef%20R3%20Vertical%20Contour%20Plot%20%28normalized%29.png




Additional measurements

Near-Field Response
Nearfield response of individual drive units:
Nearfield%20Driveunits%20%26%20Port.png



Note the lack of a strong resonance from the port. I mention this because many speakers have ports that cause resonance in the midrange. Most measurements do not provide sufficient resolution to show these issues. However, the Klippel NFS does. And in the case of the Kef R3, there are no such issues. This is attributed to the legitimate engineering of the port, dubbed by Kef as “Flexible Port Technology”, which is detailed in the graphic below.

Kef_flex_port.png



Harmonic Distortion
Harmonic Distortion at 86dB @ 1m:
Kef%20R3%20--%20Harmonic%20Distortion%20%2886dB%20%40%201m%29.png


Harmonic Distortion at 96dB @ 1m:
Kef%20R3%20--%20Harmonic%20Distortion%20%2896dB%20%40%201m%29.png



“Globe” Plots
Horizontal Polar (Globe) Plot:
This represents the sound field at 2 meters - above 200Hz - per the legend in the upper left.
Kef%20R3_360_Horizontal_Polar.png



Vertical Polar (Globe) Plot:
This represents the sound field at 2 meters - above 200Hz - per the legend in the upper left.
Kef%20R3_360_Vertical_Polar.png






Shadow Flare Position Impact on Frequency Response

The shadow flare is the plastic trim ring that surrounds the concentric drive unit and helps provide a smooth transition from the midrange cone to the baffle.
Shadow%20Flare.png


The trim ring is designed to sit flush with the midrange cone; pushed all the way in toward the drive unit. In some cases, it has been discovered that the speakers have arrived with the shadow flare positioned outward about 1mm (thus, sitting “above” of the baffle). This is believed to simply be from shipment and is an easy fix. Simply push the flare inward, going around the ring until it is properly seated (resulting in a 0.5mm lip between the flare and the speaker cutout).

Unfortunately, as has been evidence by some in-room measurements I have seen, many people are not aware that this is an issue and think nothing of it and the ill-effects of the improper positioning of the flare. Therefore, I did some investigating into the matter and have provided the results below.

Kef%20R3%20Response%20Variance%20per%20Shadow%20Flare%20Position.png




As you can see, the position of the flare matters. As illustrated by the red curve, when the flare is sticking above the surface of the baffle and not pressed all the way in - to align with the midrange cone - the response dips as much as 5dB at approximately 1.3kHz. Per the blue curve, when the flare is pushed inward to align with the baffle face - but still not pushed all the way in - the response dips about 2dB at 1.1kHz. When the flare is pushed all the way in (black curve), the 1-2kHz region dip is resolved and instead you have a mild 0.50dB dip centered around 700Hz.

The bottom line is If the shadow flare isn’t pushed all the way in there is a dip in response. One would think that flush with the baffle would be the way to go. But nope. And when you look more closely at the flare/midrange transition point it makes sense why. The shadow flare pushed all the way in (leaving a small lip between the flare and the speaker cutout) makes the flare flush with the surround edge. Any position out from that - like flush with the baffle - leaves a small gap and causes the response to dip ~1kHz. The further out the shadow flare, the more drastic the dip. You want the shadow flare to meet the drive unit, not the baffle. So, make sure the trim ring is pressed in and not sticking out above the baffle.



In-Room Measurements from the Listening Position

Below is a photograph of the speakers set up in my living room. The speakers were placed approximately 1.2m from the front wall (not the cabinets; but the actual wall). The listening position was approximately 4 meters from the speakers.

DSC09584.JPG


Below is the actual measured in-room response (with no DSP correction). This is a spatial average taken over approximately 1 cubic foot. As you can see, the actual in-room response aligns quite well with the prediction generated from the SPIN data. Pretty cool to see how anechoic measurements can reliably predict the actual in-room response. I feel many others often overlook this powerful benefit of the SPIN data.

Black = Predicted In-Room Response from SPIN data
Teal = Actual In-Room Measured Response from Main Listening Position

PIR%20vs%20MIR.png


The prediction is quite accurate down to approximately 500Hz. Below this we see more deviation from the prediction. This is expected. The room takes over as you enter mid-to-low frequencies. Aside from the room dimensions, my couch, the back wall behind where I sit, the end table and the lamp near the listening position all influence the measured response. The dip from 150-400Hz is caused by the rear wall and/or couch as when the microphone is moved into the center of the room the dip fills in. Overall, what we see here is that the anechoic data can be conveniently used to predict the actual response one would expect to see in their own room.



Parting / Random Thoughts
I encourage you to watch my YouTube review for more details but a quick few notes:
  • I love this black on black colorway.
  • As I mentioned above, there is no coloration or resonance caused by the port. I note this because many of the speakers I have tested have midrange resonances caused by the port or passive radiator. There is no hint of that at all in this speaker. A welcomed change.
  • The data does not indicate any resonances from anything. It is quite a neutral response, aside from the lifted treble on-axis. Moving to about ±10° horizontally and vertically, the treble is slightly reduced to provide a more neutral signature. For that reason, I would encourage you to experiment with toe-in and placement. You may find you like being on-axis or you may find you prefer the speakers toed in or out slightly. However, I would not go beyond ±20° as the response begins to drop above 8kHz.
  • Running these speakers full-range (20Hz to 20kHz), they have nice kickdrum but not quite enough. The harmonics of the kickdrum, however, are quite nice and give a nice fullness to the kicks, even though the fundamental notes (50-60Hz) need help.
  • Along that same token, I find these speakers to not do well in a “dead” room. They did much better in my living room than they did in my home theater, where the latter has copious sound absorption throughout.
  • At approximately 4m listening distance, I found the max SPL to be about 95dB. Exceeding this resulted in an unpleasant sound for a variety of music. 95dB in-room at 4m is pretty loud and when you pair these speakers with a subwoofer, the max SPL is increased a bit more.
  • In John Mayer’s “Free Fallin” (a live Tom Petty cover), I loved the timbre of his voice. And the air of the sound produced by the audience.
  • The layering of these speakers is unmatched, to date. The soundstage isn’t terribly wide (I prefer a wider soundstage). However, the layering and the overall depth of the soundstage is incredible. The soundstage extends deep from front to back (with the right source music, of course). It is one of my favorite things about these speakers. A good example of this is in Fleetwood Mac’s “The Chain” as well as Phillip Bailey’s “Easy Lover” (at the 3:00 mark, where Phil Collins gets down on the drums).
  • 2.5kHz sounded harsh to me and I couldn’t tell for sure if it was the speaker or the room. The data does not indicate it being the speaker itself. And in that same vein, the only thing in the data that might make sense as to a culprit is the expansion of directivity around this point. This could simply be coincidence.
  • While using the speakers full-range is OK, I found that when I added a subwoofer (SVS SB-2000 Pro and SB-3000, separately), the entire sound became immensely more enveloping. Somehow, it even seems to increase the overall sense of “space” these speakers provide with the right recording. For that reason, I do suggest a subwoofer with these speakers. I suggest a crossover in the neighborhood of 60-80Hz. I’ve had good luck with the SVS subwoofers I’m currently reviewing and with their built-in DSP, I was able to resolve a couple room modes easily and take the system to a new level of fidelity.
  • I used these speakers with the Parasound NewClassic 200 Integrated Amplifier. This integrated amplifier has 110w @ 4 and 8 ohms and was adequate to provide the output levels I needed at 4 meters listening distance. However, if you have a seating distance of more than 4m and want to listen at louder than - say - 95dB, I would suggest more power. I was also able to use the crossover within the Parasound to split the signal between the speakers and the SVS subwoofer.
  • Make sure to push the trim rings all the way in.
As stated in the Foreword, this written review is purposely a cliff’s notes version. For more details about the performance (objectively and subjectively) please watch the YouTube video.



Support / Contribute
If you like what you see here and want to help me keep it going, please consider donating via the PayPal Contribute link located below. Donations help me pay for new items to test, hardware, miscellaneous items and costs of the site’s server space and bandwidth. All of which I otherwise pay out of pocket. So, if you can help chip in a few bucks, know that it’s very much appreciated.
https://www.erinsaudiocorner.com/contribute/
Hello, Would you say that KEF Reference 1 speakers are another level up as compared to the R3 tested?
 

eddantes

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Not gonna judge... I do have Ace of Base and more improtantly, Boney M, to answer for... Nice review.

But I do find it interesting that the subjective seems to show up more in this review than the others. I wonder if the experience of this speaker from your HT to LR kinda rocked you a little? It's clear that "the room" is the thing here, which makes me wonder if there's a way to measure our rooms in such a way that allows some kind of standardization/normalization, which would predict the effect you described? And that in turn would allow us to better judge the calcualted PIR of the speaker... Sorry for the random thought of the week...
 
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hardisj

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Not gonna judge... I do have Ace of Base and more improtantly, Boney M, to answer for... Nice review.

I like me some Ace of Base.

But I do find it interesting that the subjective seems to show up more in this review than the others.

It only shows up more than the DD8C review I just did because, ironically, the DD8C was so good that I had little to talk about... there's only so many ways you can say "this is awesome". But with the Kef there were some tradeoffs I felt were worth discussing. All my other reviews have had as much subjective discussion/feedback.
 
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rynberg

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So should i get R3 with sub or the BMR with sub :) listening distance is 2.8-3.0 meters ?
Looking only at the Spin graphs, the tonality of the KEF seems to win out.

I just did a comparison test of several bookshelves (attempted blind and in mono)...the KEF R3 always sounded tonally accurate but the sound was also always tied to the box. I definitely have a strong preference for wide dispersion and the KEF fails miserably at that.
 

MZKM

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I just did a comparison test of several bookshelves (attempted blind and in mono)...the KEF R3 always sounded tonally accurate but the sound was also always tied to the box. I definitely have a strong preference for wide dispersion and the KEF fails miserably at that.
Yeah, it does better in narrow rooms.
 

Mnyb

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Yeah, it does better in narrow rooms.

Please elaborate , narrow rooms ?

The placement I have to use for any speaker is on the long wall of my room and it’s prefered in most rooms I’ve had as you need a really big room or square room to select the shorter wall . You will get very close to sidewalls otherwise.
 

tuga

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Nearfield response of individual drive units

Was each driver measured independently (only one driver playing at a time) or is this somehow estimated from the speaker playing full range (which in my view is not the actual nearfield response of individual drive units)?
 

MZKM

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Please elaborate , narrow rooms ?

The placement I have to use for any speaker is on the long wall of my room and it’s prefered in most rooms I’ve had as you need a really big room or square room to select the shorter wall . You will get very close to sidewalls otherwise.
KEF speakers are not wide dispersion, so their soundstage isn’t large in a decently big room. However, in a narrow room the side wall reflections are stronger, so a narrow dispersion speaker may be preferred.
 

Mnyb

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KEF speakers are not wide dispersion, so their soundstage isn’t large in a decently big room. However, in a narrow room the side wall reflections are stronger, so a narrow dispersion speaker may be preferred.

Thank you.

Some things needs to be quantified in my mind ( not by you personally ) what is a large room , a small room high ceiling low ceiling .

This vary culturally and bettwenn cities and country side .

Or makers of home speakers should also quantify expected listening distance just like the makers of studio monitors ?

Hint @hardisj ask for example KEF what is the preferred listening distance :) I'm quite sure there is one even if they wont say in an official paper .
The white paper for ther R series says "smaller room" but the term is quite vague give the cubic meters or a rough w*l*h and listening distance o_O

So KEF's hint of "smaller room" for the R3 does rhyme with @MZKM assessment :)
 

Ron Texas

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@Mnyb KEF recommends something like 6' to 10' apart for the speakers and an equilateral triangle for both the R3 and LS50. I recall the same numbers for several models of the B&W 600 series. To call a room small, medium or large is a vague. I have seen layouts for UK homes in this forum with rooms which would be called tiny in the US. To make it more confusing how does one evaluate rooms which are open to other rooms?
 
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