KEF R300 Review with Measurements?

[ssashton]

Is there a good review of the KEF R300 anywhere that allows me to see the difference between the R300 and R3?

 

[Matias]

Best measurements I could find:

KEF R300 playground - measurements of raw drivers

Measurements are done in room so 4,5ms gate is best i can do which translates to about 220Hz gate frequency. 1m distance. Measurements done 0-90 degrees in 10deg increments. I don't believe i'll be dragging these to the parking lot any time soon, but who knows. Until then: Averaging them:

www.diyaudio.com

 

[olieb]

Maybe you know this already, but this are the best infos I know of about the R300 and its drivers.

Kef R300 playground - measurements of raw drivers

www.diy-hifi-forum.eu

Kef R300 Speaker Drive Unit Testing

Kef R300

www.erinsaudiocorner.com

@Matias beat me to it. ;-)

EDIT:
But to be a bit more useful I took my Umik and made some distortion measurements of the coax with crossover in the original cabinets.
R3 96dB/1m measured at 0.5m.
I checked my setup and somehow the calibration is off.
The voltage was 2.3Vrms, that is more like 86dBspl

R300 96dB/1m measured at 0.5m
The voltage was 2.3Vrms, that is more like 86dBspl

The R3 has a flatter FR and somewhat lower H3. H2 is a bit higher though.
The coax in the R300 is not bad at all.
I remember that I measured these speakers before but I could not find the file. IIRC the woofer in the R300 is one tier below the one in the R3, it has significantly (8-10dB) more distortion (similar to the one in the Concerto meta), but I am too lazy to measure again.

Attached the full measurement file with 86dB/1m measurements, too.

 

[ssashton]

Thank you yes I found those and they are useful, however I was hoping for a direct A/B comparison between the R300 and R3, in particular midrange and tweeter distortion.

Was the R300 before Amir was doing reviews?

 

[Blueprint]

IIRC correctly KEF focused a great deal on low/midrange distortion with the R3 range and tweeter distortion with the Meta range, so I would expect the biggest difference between R300 range and R3 range to be midrange distortion, with the R3 range sounding cleaner in that department.

There are NRC measurements for the R500 and R100. I don’t know what you can take from those for the R300 but they’re easy to find. As other have stated, the R300 drivers have been measured in a few places.

The only other thing I’d mention is that the R3 range was the first range KEF explicitly recommended full toe-out (point straight ahead) for their speakers. As a result the R3 has a much-misunderstood high frequency bump that led to people finding them bright. The R300 is designed to be toed in, I believe.

 

[tw 2022]

I've talked to a couple of folks that liked the r300 quite a bit, looking at the measurements earlier in this thread , I'd venture to guess that they aren't much different than the r3 ( which I heard and liked a lot )....

 

[ssashton]

Maybe you know this already, but this are the best infos I know of about the R300 and its drivers.

Kef R300 playground - measurements of raw drivers

www.diy-hifi-forum.eu

Kef R300 Speaker Drive Unit Testing

Kef R300

www.erinsaudiocorner.com

@Matias beat me to it. ;-)

EDIT:
But to be a bit more useful I took my Umik and made some distortion measurements of the coax with crossover in the original cabinets.
R3 96dB/1m measured at 0.5m.
I checked my setup and somehow the calibration is off.
The voltage was 2.3Vrms, that is more like 86dBspl
View attachment 473558

R300 96dB/1m measured at 0.5m
The voltage was 2.3Vrms, that is more like 86dBspl
View attachment 473559
The R3 has a flatter FR and somewhat lower H3. H2 is a bit higher though.
The coax in the R300 is not bad at all.
I remember that I measured these speakers before but I could not find the file. IIRC the woofer in the R300 is one tier below the one in the R3, it has significantly (8-10dB) more distortion (similar to the one in the Concerto meta), but I am too lazy to measure again.

Attached the full measurement file with 86dB/1m measurements, too.

Oh, thanks so much! Is this the non-meta R3?

The 3rd harmonic is nicely reduced on the R3.

It leaves me wondering exactly what changes were made to the newer uni-q. Was there ever a video with Jack or David going in to details? I only find that for the meta version.

I find it interesting to see they started using a small roll in the surround, even though it is mid only - I had always thought a flat surround like the older R300 was theoretically better where excursion is minimal because it is more linear. Look at drivers like the Audax PR170 or the new SB Nero 6MRN150, or even Genelec The Ones, where they seem to have copied the Z flex idea. Then again Seas also used a tiny roll on their latest coax.

 

[olieb]

I checked my setup and somehow the calibration is off.

I really hate when this happens.
So I went at it again this time with the correct calibration. And I measured the woofers too.
What I said about the differences of the two different coaxes and the woofers still holds. But see for yourself.
Woofer measurements below 200Hz are contaminated with room influence and below 100Hz are useful only for a trend of distortion.
Coaxes are gate 6ms so this is quasi-anechoic.
Everything is measured from 50cm so the levels are 6dB higher than "normal".
If my guess is right that the "wobble" 2k-6k in the R300 response is due to baffle and edges, then the "shadow flare" seems to do a good job in the R3.
Cursor at 1.2kHz.

Distortion measurements.

And the full measurements

 

[ssashton]

Just to help me clarify - the R300 is 11th gen coax and the R3 is 12th gen, is that right?

What was the time line on these developments I've heard about ?

Tweeter gets a reinforcement piece behind the outer edge.

Damping ring attachment added between VC and cone.

 

[ssashton]

I really hate when this happens.
So I went at it again this time with the correct calibration. And I measured the woofers too.
What I said about the differences of the two different coaxes and the woofers still holds. But see for yourself.
Woofer measurements below 200Hz are contaminated with room influence and below 100Hz are useful only for a trend of distortion.
Coaxes are gate 6ms so this is quasi-anechoic.
Everything is measured from 50cm so the levels are 6dB higher than "normal".
If my guess is right that the "wobble" 2k-6k in the R300 response is due to baffle and edges, then the "shadow flare" seems to do a good job in the R3.
Cursor at 1.2kHz.
View attachment 473772
Distortion measurements.
View attachment 473762View attachment 473763View attachment 473764View attachment 473765View attachment 473766View attachment 473767View attachment 473768View attachment 473769
And the full measurements

Wow, what a thorough reply! Thanks so much!

I'm just curious, why do you keep both R300 and R3? Two different systems?

 

[olieb]

I'm just curious, why do you keep both R300 and R3? Two different systems?

The R300 were a very good used deal and are kind of in storage. I bought the R3 later when they were in a low price offer
I still have the idea to build a multichannel setup around all these. Will see. Too many projects ;(

 

[Le Zebre]

Maybe you know this already, but this are the best infos I know of about the R300 and its drivers.

Kef R300 playground - measurements of raw drivers

www.diy-hifi-forum.eu

Kef R300 Speaker Drive Unit Testing

Kef R300

www.erinsaudiocorner.com

@Matias beat me to it. ;-)

EDIT:
But to be a bit more useful I took my Umik and made some distortion measurements of the coax with crossover in the original cabinets.
R3 96dB/1m measured at 0.5m.
I checked my setup and somehow the calibration is off.
The voltage was 2.3Vrms, that is more like 86dBspl
View attachment 473558

R300 96dB/1m measured at 0.5m
The voltage was 2.3Vrms, that is more like 86dBspl
View attachment 473559
The R3 has a flatter FR and somewhat lower H3. H2 is a bit higher though.
The coax in the R300 is not bad at all.
I remember that I measured these speakers before but I could not find the file. IIRC the woofer in the R300 is one tier below the one in the R3, it has significantly (8-10dB) more distortion (similar to the one in the Concerto meta), but I am too lazy to measure again.

Attached the full measurement file with 86dB/1m measurements, too.

Hi, i try to find how good are the q concerto meta compared to the r300 (which i had a few years ago). You say the distorsion is the same ? what are the biggest differences between those 2 speakers ?
Thanks

 

[Le Zebre]

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