Dutch & Dutch 8C Quasi-Anechoic Spinorama and Measurements

[napilopez]

If the predicted in room response was the same between 2 different speakers, but they got there in different ways, would they sound the same size?

They would likely not, especially not from the same space. Even speakers with the same DI/ERDI curves would sound different. Remember that for the most part it's the horizontal curves that define the sense of spaciousness, while vertical measurements seem to primarily affect timbre. Even among horizontal curves it depends on how the speaker interacts with your room.

Of individual curves the ERDI is probably most useful for defining a sense of spaciousness in a mostly front firing speaker, but again, it's not a complete picture, just a useful summary.

 

[napilopez]

For those curious, here's the in-room response on the D&D 8C after doing nothing more than inputting distances to the sidewalls. This is an average of 7 measurements in roughly 2ft x1.5 ft grid around my LP 10 feet from the speakers, with both speakers firing. I used almost no toe-in during these measurements, putting them roughly 15-20 degrees off axis.

In the dashed white line you can see the Predicted in-room response from my measurements. Note that the PIR is based on on-axis measurements, so the treble is naturally a bit higher.(plus you can't count on accuracy there too high up anyway.) I find it particularly interesting how the PIR predicts the little bump at 2Khz.

Below the 8C are similar averages of the KEF R3 and B&W Formation Duo. I think I used a wider grid for these I believe - and I was probably a bit less methodical overall - so don't take the treble too seriously, but you can see how much messier everything is below 1Khz, and in particular how prominent the 80 and 120Hz nulls are. The 80Hz null is still present in the 8C, but is significantly lower in amplitude.

The 8C has easily the most ideal such curve I've gotten with a speaker out of the box, without thorough room EQ and sub integration. I could EQ them a bit flatter, sure, but subjectively I noticed little difference after trying to EQ them further. Just another sign of how good these speakers are.

 

[QMuse]

They would likely not, especially not from the same space. Even speakers with the same DI/ERDI curves would sound different.

Heh, it would be interesting to find out if listeners would be able to tell 2 speakers apart assuming similar PIR, DI/ERDIs and bass extension. Personally I have some doubts there..

 

[napilopez]

Heh, it would be interesting to find out if listeners would be able to tell 2 speakers apart assuming similar PIR, DI/ERDIs and bass extension. Personally I have some doubts there..

Again, depends on how they arrive at those curves. You could have wide vertical directivity but narrow horizontal directivity, for instance. Or you can imagine a speaker with a horizontal driver setup could theoretically measure similar to one with a vertical setup but they almost certainly wouldn't sound the same.

I do wonder how similar speakers have to be before you can't tell them apart anymore though.

 

[Purité Audio]

If you slightly adjust the target curve then the Kiis and 8Cs are pretty similar.
Keith

 

[mitchco]

@Purité Audio has it. No "room eq" on these, just using the onboard controls measured at the LP some 9ft away:

Zoom in on 1 kHz on up:

While I don't have an easy way of switching the speakers in and out, casual listening, sounded incredibly similar to my ears. In a proper DBT, I doubt I could tell them apart... Using DSP to eq can make the fr virtually identical. I think this is probably close enough.

 

[QMuse]

Again, depends on how they arrive at those curves. You could have wide vertical directivity but narrow horizontal directivity, for instance. Or you can imagine a speaker with a horizontal driver setup could theoretically measure similar to one with a vertical setup but they almost certainly wouldn't sound the same.

I do wonder how similar speakers have to be before you can't tell them apart anymore though.

I was assuming similar horizontal directivity as IMO that is more important than vertical directivity.

 

[Soniclife]

Interesting how the 'house curve' if the 8c and the R3 is quite different, the Kef has as a linear slope, the 8c more of a Harman curve with most of the change going on below 200hz. Deliberate design decision from each company?

 

[napilopez]

Interesting how the 'house curve' if the 8c and the R3 is quite different, the Kef has as a linear slope, the 8c more of a Harman curve with most of the change going on below 200hz. Deliberate design decision from each company?

I wouldn't look too much into the top half of the response there - as mentioned my averaging was a bit different for the R3 so I can't ensure consistency there; it was mainly to show off how effective the 8C is at removing room messiness in the bass.

I posted this image of the R3's response at 1m, 2m, and 3m in the R3 thread to show what different in-room responses might look like depending on toe in, distance , technique, etc. The white dashed line was Amir's PIR. You can see that at 2m with one speaker firing on axis, it matches quite nicely.

Otherwise I can't compare them too much without having heard them side by side.

 

[Soniclife]

I wouldn't look too much into the top half of the response there - as mentioned my averaging was a bit different for the R3 so I can't ensure consistency there; it was mainly to show off how effective the 8C is at removing room messiness in the bass.

I posted this image of the R3's response at 1m, 2m, and 3m in the R3 thread to show what different in-room responses might look like depending on toe in, distance , technique, etc. The white dashed line was Amir's PIR. You can see that at 2m with one speaker firing on axis, it matches quite nicely.

View attachment 55328

Otherwise I can't compare them too much without having heard them side by side.

It's more the below 1k part I was looking at, the R3 looks quite consistent there in your measurements, and it's a different shape to the 8c. The R3 looks like a great speaker, the 8c also looks great but with a slightly different house sound, but it clearly does work well in real rooms.
I'll be interested in how the Kii 3 works if you ever get it in, it's cardioid goes a little lower so might tame your 80hz null problem.

 

[John Atkinson]

Dutch & Dutch 8C (wave-guided cardioid narrow baffle box with rear woofers)

Kef Blade 2 (wave-guided coax narrow baffle box with side woofers)

PSB T3 (wave-guided narrow baffle box)

Sonus Faber Stradivari (650mm wide baffle box)

Jamo R907 (open baffle)

Gradient Helsinki 1.5 (waveguided coax open baffle)

MartinLogan Montis (planar dipole above 300Hz)

Avantgarde Uno Nano (horns above 350Hz)

MBL Radialstrahler 101E Mk.II (omni)

I have no objection to you posting my measured data to illustrate the points you are making, but when you do so, please acknowledge the source and add the URLs to the original measurements if possible.

My followup on the Dutch & Dutch 8c is published in the April 2020 issue of Stereophile magazine and will be reprinted on www.stereophile.com in the next few days. The original review measurements can be found at https://www.stereophile.com/content/dutch-dutch-8c-active-loudspeaker-system-measurements .

John Atkinson
Technical Editor, Stereophile

 

[tuga]

I have no objection to you posting my measured data to illustrate the points you are making, but when you do so, please acknowledge the source and add the URLs to the original measurements if possible.

My followup on the Dutch & Dutch 8c is published in the April 2020 issue of Stereophile magazine and will be reprinted on www.stereophile.com in the next few days. The original review measurements can be found at https://www.stereophile.com/content/dutch-dutch-8c-active-loudspeaker-system-measurements .

John Atkinson
Technical Editor, Stereophile

I usually do. Will add a link to Stereophile to that post.
But I think that many here know where these graphs come from anyway.

 

[John Atkinson]

I usually do. Will add a link to Stereophile to that post...

Thanks.

John Atkinson
Technical Editor, Stereophile

 

[tuga]

Thanks.

John Atkinson
Technical Editor, Stereophile

By the way, Stereophie's website used to add the text "Read more at " followed by a link to the page when we copy-pasted a piece of text from the site but no longer does. I think this was helpful.
For example:

Finally, as well as the clean, uniform initial decay confirming the time-coherent behavior, the CS1.5's cumulative spectral-decay, or waterfall, plot (fig.8) shows a couple of low-level resonant modes in the mid-treble, exactly as MK predicted. I'm surprised he was bothered by this behavior, but I suspect that it is not generally masked by the music.
Read more at https://www.stereophile.com/content/thiel-cs15-measurements

 

[John Atkinson]

My followup on the Dutch & Dutch 8c is now reprinted on the Stereophile website: https://www.stereophile.com/content...e-loudspeaker-system-john-atkinson-april-2020

Note that fig.1 was omitted from the print version due to lack of space. Note also that fig.3 compares the spatially averaged in-room response of the REW-corrected 8cs with that of the uncorrected KEF LS50s. Having just read Amir's review of the LS50 on ASR, I think this graph and my following comments correlate nicely with Amir's analysis of the KEF's tonal balance.

John Atkinson
Technical Editor, Stereophile

 

[Frank Dernie]

My followup on the Dutch & Dutch 8c is now reprinted on the Stereophile website: https://www.stereophile.com/content...e-loudspeaker-system-john-atkinson-april-2020

Note that fig.1 was omitted from the print version due to lack of space. Note also that fig.3 compares the spatially averaged in-room response of the REW-corrected 8cs with that of the uncorrected KEF LS50s. Having just read Amir's review of the LS50 on ASR, I think this graph and my following comments correlate nicely with Amir's analysis of the KEF's tonal balance.

John Atkinson
Technical Editor, Stereophile

I have subscribed to Stereophile for decades and HiFi News for longer, now by download though.
The publication of the articles on the Internet for free only a couple of weeks after my subscription copy arrives is making subscription a less attractive proposition, even more so with HiFi News since the Pocketmags paid issues won't come up on my new iPad.
Hope you are still watching the F1- cheers Frank

 

[John Atkinson]

I have subscribed to Stereophile for decades and HiFi News for longer, now by download though.

Thanks Frank. Good to hear from you. Do you still have a connection with the F1 paddock? I seem to remember you got a namecheck in Adrian Newey's book.

The publication of the articles on the Internet for free only a couple of weeks after my subscription copy arrives is making subscription a less attractive proposition, even more so with HiFi News since the Pocketmags paid issues won't come up on my new iPad.

It takes 3-4 weeks for the new issue's content to appear on the website, so there is still an advantage to having a subscription.

Hope you are still watching the F1- cheers Frank

Been going to the US GP since the first one in Austin and last year went to Silverstone also. But this year, while we have tickets and a hotel room booked for the Canadian GP in June, I suspect that that will be postponed or canceled.

John Atkinson
Technical Editor, Stereophile

 

[Frank Dernie]

Thanks Frank. Good to hear from you. Do you still have a connection with the F1 paddock? I seem to remember you got a namecheck in Adrian Newey's book.



It takes 3-4 weeks for the new issue's content to appear on the website, so there is still an advantage to having a subscription.



Been going to the US GP since the first one in Austin and last year went to Silverstone also. But this year, while we have tickets and a hotel room booked for the Canadian GP in June, I suspect that that will be postponed or canceled.

John Atkinson<BR>
Technical Editor, Stereophile

I retired from F1 after 35 years. My contacts now are via friends who still work there, some of whom have risen quite high over the years.
My fishing mate Ross Brawn who was my lab technician in 1979 is now the new Bernie, I pop in to see Frank Williams every 3 weeks or so but he isn't well, and have lunch with Patrick Head when he is round about. Lots or reminiscing and BS.
It could be my age but I am grateful to have worked in what seems to me now to have been a golden age of F1 when one could get involved in everything. As well as doing all the aerodynamics at Williams for 10 years I also ran most of the tests to do the car set-up, invented and developed to race wins the active suspension whilst running the cars at 50% of the races. It was long hours but nowadays with 10x more money there are far more people but one has to be more specialist so my fun would not be possible today.
One of my best friends is head of Aero at Ferrari and has over 120 people, I had 1 technician to run the tunnel when I was at races and tests an 2 model makers...

 

[Frank Dernie]

I seem to remember you got a namecheck in Adrian Newey's book.

I never worked with Adrian but he was my replacement at Williams a couple of years after I left and they decided they needed another aero guy.
I haven't read his book.

 

[napilopez]

Good to see you here @John Atkinson; it was great to chat with you a few weeks ago. I read your followup on the 8C, and appreciate your added insight to in-room performance.