KEF R Series with MAT white paper

[sweetchaos]

Erin reviewed the R3 Meta today!

KEF R3 Meta - Review & Measurements by Erin

https://www.erinsaudiocorner.com/loudspeakers/kef_r3_meta/

www.audiosciencereview.com

 

[songOVERsound]

What is it about PMC speakers that makes the bi-wirable but not bi-ampable? Something about their crossover topology?

I stumbled across some of the jargon I was referring to

“Funny thing is the PMC IB1S-AIII vs the IB1S. They both have passive crossovers (this is a real sticking point with me and their speakers because the "A" isn't active here but "activated" which just means they've bolted on an amplifier instead of terminals but no active crossover.)”

 

[resh34]

I will be very honest with you, I could give you room sizes, but they will probably mean nothing once you account for all the variables such as proportions, building materials, treatment, speaker positions, listener positions, etc. As well as your listening habits (type of music and how loud you want to play it). As you know the larger the room, and the farther away the listener is to the speakers, the louder they will need to be played to sound as loud. The R3 Meta is surprisingly very capable of producing ample clean bass but it does have a ceiling that becomes obvious in large/lossy rooms at high volumes. R11 Meta goes extremely loud before it distorts but in a small room where the stereo triangle will be less than 3 metres per side, the LF array is relatively too big wrt the listener so the stereo image will suffer. If you're in the UK, a lot of people find R5 the right compromise between size, footprint, bass extension and distortion capabilities (and price) for the size and construction of living rooms we have.

Hi David - Thanks for taking the time! Like a few others the white paper and all the comments here has really helped in narrowing down my next speaker purchase... alas I'm now stuck on the R11 vs R7 dilemma..

• from a design perspective what are the intended benefits of the R11 over the R7 beyond the additional low frequency extension and higher output before encountering distortion?
• how and to what extent are the port bungs intended to impact the low frequency response (including the intended difference in plugging one vs both)? Would it reduce the effective low frequency reproduction of the R11 to be closer in output to the R7?
• the point made on relative distance of the speaker array to the listener was very interesting and has also made me wonder - would it be expected that the stereo image of the R7 would be superior at a listening distance of 3m compared to the R11 (given the R7 would be well beyond the minimum distance, but the R11 would be at the minimum)? My listening distance would be very close at around ~2.9m...

I did also notice the R11 frequency response appears to be slightly smoother overall (certainly around the tweeter crossover point) vs the R7. Is this purely a frequency response difference, or is there something more this is alluding to that sets them apart?

 

[songOVERsound]

I purchased the r11 and will be listing to them very close up in a studio setting but I understand it might not work so I can have plenty of other uses for them.

One can also modify the r11 to disable the very top and bottom woofers. There’s a lot you could do. I mainly just took advantage of the sale

 

[BrokenEnglishGuy]

I purchased the r11 and will be listing to them very close up in a studio setting but I understand it might not work so I can have plenty of other uses for them.

One can also modify the r11 to disable the very top and bottom woofers. There’s a lot you could do. I mainly just took advantage of the sale

How much is very close?

 

[songOVERsound]

How much is very close?

About 4-5 feet. Will eventually have Trinnov which could help slightly with imaging. Most of my work is above 400 hz but I understand, in context, if the entire FR isn’t correct it can throw off spectral balance throughout all frequencies

 

[BrokenEnglishGuy]

About 4-5 feet. Will eventually have Trinnov which could help slightly with imaging. Most of my work is above 400 hz but I understand, in context, if the entire FR isn’t correct it can throw off spectral balance throughout all frequencies

oh i see
i would pick the r7 all day for that distance.. the Trinnov will be mandatory !

 

[HarmonicTHD]

Hi David - Thanks for taking the time! Like a few others the white paper and all the comments here has really helped in narrowing down my next speaker purchase... alas I'm now stuck on the R11 vs R7 dilemma..

• from a design perspective what are the intended benefits of the R11 over the R7 beyond the additional low frequency extension and higher output before encountering distortion?
• how and to what extent are the port bungs intended to impact the low frequency response (including the intended difference in plugging one vs both)? Would it reduce the effective low frequency reproduction of the R11 to be closer in output to the R7?
• the point made on relative distance of the speaker array to the listener was very interesting and has also made me wonder - would it be expected that the stereo image of the R7 would be superior at a listening distance of 3m compared to the R11 (given the R7 would be well beyond the minimum distance, but the R11 would be at the minimum)? My listening distance would be very close at around ~2.9m...

I did also notice the R11 frequency response appears to be slightly smoother overall (certainly around the tweeter crossover point) vs the R7. Is this purely a frequency response difference, or is there something more this is alluding to that sets them apart?

What about the R7 and one or even better two subs. This way you position the R7 for best “upper” frequency / soundstage (SBIR) and the subs are positioned for “best” lower frequencies (room modes, below ca 250Hz). As you never get both objectives optimized in one spot with a single pair of R11 (or any other single speaker pair). Yes you need a RoomEQ system and a measuring mic. Or even better R11 plus two subs. ;-)

(I run my Reference 3 with two KF92s btw).

 

[songOVERsound]

oh i see
i would pick the r7 all day for that distance.. the Trinnov will be mandatory !

Good point. If I end up liking the r11’s I’ll be looking for deals on the R7’s

 

[BrokenEnglishGuy]

Good point. If I end up liking the r11’s I’ll be looking for deals on the R7’s

if im not wrong the kef guys here recommend like 2 - 3 meters if im not wrong for R11, the R7 is for more close distance... i the r7 here have no problem

 

[kolestonin]

I own R3 Meta's and my understanding is the recommended distances part of the manual is common for all models of the series.

 

[resh34]

What about the R7 and one or even better two subs. This way you position the R7 for best “upper” frequency / soundstage (SBIR) and the subs are positioned for “best” lower frequencies (room modes, below ca 250Hz). As you never get both objectives optimized in one spot with a single pair of R11 (or any other single speaker pair). Yes you need a RoomEQ system and a measuring mic. Or even better R11 plus two subs. ;-)

(I run my Reference 3 with two KF92s btw).

I should have mentioned I would be running them with a sub (sb2000 pro, although the KF92 would be a very nice match aesthetically now that you’ve mentioned it…). The older r series (non meta) seemed to have the crossover points all the same regardless of r7 or r11 and in that case I’d probably have gone with the r7… however, the meta seems to have some differences in crossover points across the board and what looks to be a resulting difference in the frequency response above ~300hz

 

[songOVERsound]

I own R3 Meta's and my understanding is the recommended distances part of the manual is common for all models of the series.

I would be careful with those guidelines. If you follow them, with having just one woofer, you can quite easily get into a constructive speaker boundary interference situation. Check out 2:30 of the vid, they explain it well. All speakers have the same or similar radiation unless they are cardioid or bass steering like Genelec’s systems can do

This is one of the reasons I’m so interested in trying the R11’s because of the vertical array of woofers.

The meta’s crossing over at 320 hz vs 400 will be better yet because it’s far enough from the Schroeder frequencies, yet allows the midrange/tweeter drivers to be more of a point source

Edit: I forget.. I am more nearfield and I’m not sure that SBIR has the same amount of impact or degradation with farther listening distance

 

[aarons915]

I would be careful with those guidelines. If you follow them, with having just one woofer, you can quite easily get into a constructive speaker boundary interference situation. Check out 2:30 of the vid, they explain it well. All speakers have the same or similar radiation unless they are cardioid or bass steering like Genelec’s systems can do

This is one of the reasons I’m so interested in trying the R11’s because of the vertical array of woofers.

The meta’s crossing over at 320 hz vs 400 will be better yet because it’s far enough from the Schroeder frequencies, yet allows the midrange/tweeter drivers to be more of a point source

Edit: I forget.. I am more nearfield and I’m not sure that SBIR has the same amount of impact or degradation with farther listening distance

I think it still does, I have had dips in most of my rooms around the 100Hz range consistent with a placement about 3ft from the walls, multiple woofers might help but to me that is massive overkill considering LS50's provide enough SPL for me. I find the better solution is to make sure your mains are as far away from the walls as you can put them with multiple subs in the corners with your crossover around 100Hz. This allows the subs to help out with this typical SBIR dip and it will be minimally audible and not a big deal, a higher crossover point also lessens the requirement for multiple woofers depending on your listening levels.

 

[songOVERsound]

I think it still does, I have had dips in most of my rooms around the 100Hz range consistent with a placement about 3ft from the walls, multiple woofers might help but to me that is massive overkill considering LS50's provide enough SPL for me. I find the better solution is to make sure your mains are as far away from the walls as you can put them with multiple subs in the corners with your crossover around 100Hz. This allows the subs to help out with this typical SBIR dip and it will be minimally audible and not a big deal, a higher crossover point also lessens the requirement for multiple woofers depending on your listening levels.

I wish I could get spacing from all boundaries, but I’m in kind of a tightly spaced studio/room.

I actually got a decent frequency response until I started adding more and more acoustic treatment. My issue with my current setup is because of the floor bounce - verified by measurements. A deep and wide null centered at 150 hz. This is because I have 8 ft ceilings and my optimal speaker height is in the middle. I have the ceiling fully treated as low as I can go without feeling like I’m in a coffin. But obviously I can’t treat the floor.

I have some peaks but they follow a tilt that I want anyways. Im fine with EQing things down, but avoid using eq to boost if possible due to SBIR only getting more activated and distortion. Frequency response is only one component. I have been getting my spectral decay and impulse response dialed in getting an even reverb time.

Anyways, I didnt really want to cross over to a sub at 175 hz, but it has crossed my mind. Was going to get two Rythmik FM8 subs before seeing the deal on the KEF r11’s which I can use for all sorts of stuff if it doesn’t work out in my studio. Win-win haha

 

[kolestonin]

would be careful with those guidelines.

Definitely.
I simply added the data as @BrokenEnglishGuy mentioned/asked about kef's suggestions.
I always take under consideration what are the generic guidelines of the manufacturer, knowing though that what will determine the final placement is the room.
I my case 30cm from back wall was the minimum distance the wall stopped interfering negatively(to my ears) with the speakers. I now have them at 45cm. As for the boundaries I would say everything above 50cm will work. Regarding the listening distance, I tried different placements between 2m and 3m with no audible, other than loudness, difference I would say.

If you say you are boundaries restricted the bigger speaker will be a bigger 'problem' in theory. Or not? You also say you intend to place them nearfield. In my opinion the best choice of R series for you usage scenario is R3. Give them a try and I am pretty sure you will be fully satisfied.

 

[pjn]

I would be careful with those guidelines. If you follow them, with having just one woofer, you can quite easily get into a constructive speaker boundary interference situation. Check out 2:30 of the vid, they explain it well. All speakers have the same or similar radiation unless they are cardioid or bass steering like Genelec’s systems can do

This is one of the reasons I’m so interested in trying the R11’s because of the vertical array of woofers.

The meta’s crossing over at 320 hz vs 400 will be better yet because it’s far enough from the Schroeder frequencies, yet allows the midrange/tweeter drivers to be more of a point source

Edit: I forget.. I am more nearfield and I’m not sure that SBIR has the same amount of impact or degradation with farther listening distance

A nice concise video - REW is your friend!

 

[songOVERsound]

Definitely.
I simply added the data as @BrokenEnglishGuy mentioned/asked about kef's suggestions.
I always take under consideration what is the genetir guidelines of the manufacturer, knowing though that what will determine the final placement is the room.
I my case 30cm from back wall was the minimum distance the wall stopped interfering negatively(to my ears) with the speakers. I now have them at 45cm. As for the boundaries I would say everything above 50cm will work. Regarding the listening distance, I tried different placements between 2m and 3m with no audible, other than loudness, difference I would say.

If you say you are boundaries restricted the bigger speaker will be a bigger 'problem' in theory. Or not? You also say you intend to place them nearfield. In my opinion the best choice of R series for you usage scenario is R3. Give them a try and I am pretty sure you will be fully satisfied.

Yes, the R11 an odd choice to say the least, but I’m mainly taking advantage of the sale. I’ll be able to use them life-long in some capacity and the value is easily there.

I don’t believe a big speaker in a smaller room is a problem unless you can’t place them properly, so if that’s what you meant then yeah. But the R11’s are only 7 inches wide. They are a bit deep at 15 inches, but I might be able to make it work having them closer to the front wall

Your distance from the front walls OR side walls (but not both, and corners will give massive bass gain) will be very close to Genelecs speaker positioning guide. I am in the “acceptable” range and the dip is in the low/mids, which is not ideal but the lows and subs couple to the room well. I might put some treatment behind the speakers with scatter plates (I like to have the front wall reflective)

I have confirmed these results with measurements. Remember, the distance will be to the woofer and not the back of the speaker (since speaker depths vary)

 

[Descartes]

When will KEF update KEF-CI3160RL-THX to have metamaterial technology? The reference line is way too expensive!

 

[exm]

Hi folks, I'd like to share with you the white paper for the new KEF R Series with MAT (the newly released Meta models).

Big apologies for the delay we've had in publishing it, as I know some of you have been awaiting it since the market launch of the series. We've been a bit busy in R&D but I've made sure to include lots of interesting data and figures.

We've tried to go into as much detail as possible on the new technology in this iteration as well as adding new explanations on existing technology, so that you can have a global view of what we've achieved.

I sincerely hope you'll find it an interesting read and enjoy flicking through the pages.

Hey David, any update on the Kef supplied specs for the Reference 2 Meta? As a reminder, the R6 Meta (similar in overall specs, but obviously not a Reference build) have speciations way below the Ref 2. Basically I am looking for a good crossover recommendation for the Reference (hoping 80Hz will cut it).