Dutch & Dutch 8c Review

[TabCam]

Probably because all harmonics of fundamentals above 10kHz are outside the range of human hearing.

Why then put an FR in there until 20 kHz or much more? Human hearing is until 20kHz. Even most older can hear until 15 kHZ if they play at reference levels. Would still like to know the distortion figures until at least 20 kHz.

 

[tktran303]

Here on DIYAUDIO a dozen years ago, I think it's part of the genesis of these great speakers. There are some interesting conversations with Earl Geddes ...https://www.diyaudio.com/forums/multi-way/192737-2-waveguide-cardioid-6.html

Yeah. And John Krevskovsky’s Music and Design’a NaO II with damped U-frame cardioid sub-bass section (30Hz-120Hz). I built and enjoyed that 15 years ago...

Someone should send Amir or Erin the real groundbreakers- NaO II speakers

http://musicanddesign.speakerdesign.net/NaOIIdiscus.html

 

[ctrl]

I cannot comment on your simulation, beyond saying I'm sure it demonstrates the effects you set out to simulate ;-)

Consciously, I would never do something like that, I think
But it is never impossible that I made a mistake when creating the simulation. The BEM-LEM software is not trivial to use.

FYI slot area should be approximately Sd of driver (~220cm^2 for 8").

Okay, with 230cm² slot area, there is hardly anything left of a typical Helmholtz resonator in the impedance frequency response.

In the sound pressure curve of the slot, the resonance is still clearly visible, but the simulation is without slot damping.

Not much happens in the driver excursion, rather the opposite, as it now more and more resembles an some kind of "open-baffle". But here, too, the positive effect of the damping must still be taken into account.

It is still the case that above below a certain frequency limit, the excursion increases abruptly and can thus lead to high HD3 at a low crossover frequency.

 

[TabCam]

Most likely because mic is not calibrated above 20kHz and measurement is most likely done with 48kHz/24bit sampling. Most measurement programs limit distortion scale automatically based on sampling limits.

Seems a good explanation, thanks!

 

[ebslo]

Why then put an FR in there until 20 kHz or much more? Human hearing is until 20kHz. Even most older can hear until 15 kHZ if they play at reference levels. Would still like to know the distortion figures until at least 20 kHz.

You can hear the fundamental above 10kHz but not any of the harmonics as the 2nd harmonic of 10kHz is at 20kHz. I was speculating they may not have seen a point in measuring production of harmonics that nobody can hear.

 

[Lorenzo74]

This is a terrible, terrible suggestion. Manufacturers rewarding reviewers for positive reviews?

Apologize to have being politically incorrect ... I edited the post since I realize It was misunderstood.
thanks

 

[Massimo]

It is without question an outstanding speaker and comes pretty close to being the perfect speaker.

However, even with a speaker that costs $ 12500 a pair, one should clearly name qualitative weak points.
You have even measured $90 shelf speakers, Neumi BS5, that partly show better THD in the frequency range 50-500Hz than the 8C.

You can't single out one measurement attribute to make comparisons. How does the Neumi BS5 perform at 30Hz or at 100dB or with respect to dispersion compared to the D&D 8C?

 

[q3cpma]

You can't single out one measurement attribute to make comparisons. How does the Neumi BS5 perform at 30Hz or at 100dB or with respect to dispersion compared to the D&D 8C?

Actually, you can, since the 8c is built in a way that let us do that: it's a 2-way with an integrated subwoofer. So you can add a sub to that cheap Neumi and you'll get your bass while still keeping the low distortion (and probably even lower with the sub).

 

[Massimo]

Actually, you can, since the 8c is built in a way that let us do that: it's a 2-way with an integrated subwoofer. So you can add a sub to that cheap Neumi and you'll get your bass while still keeping the low distortion (and probably even lower with the sub).

Fair enough. So please show all measurement attributes as per Erin's review for your combination of Neumi and sub compared to the 8C which achieves ±1.5dB from 30Hz to 18kHz, 105dB full range at 4 meters, directivity and so on.

 

[ctrl]

Fair enough. So please show all measurement attributes as per Erin's review for your combination of Neumi and sub compared to the 8C which achieves ±1.5dB from 30Hz to 18kHz, 105dB full range at 4 meters, directivity and so on.

No one is claiming that the $90 speaker can hold a candle to the 8C when viewed as a whole.
The comparison should only underline that there is a weak point. I could have just as easily used the Selah Audio Purezza.

I was mainly interested in the possible reason for the high distortion values of the 8C in the range around 100Hz.
For current high-end speakers, the distortions are really high, whether audible or not, but of course only one aspect of an overall excellent speaker.

 

[John Atkinson]

I was going to resist commenting until you did the youtube review.

I noticed that you have modified the boom with copper tubing and something else.

When I started using MLSSA to measure loudspeakers, I examined the difference between the farfield response of an LS3/5a with the microphone mounted with a conventional clip and boom stand with it flush-mounted at the end of a long copper pipe. You can see the effect of the reflections from the conventional stand in fig.23 at https://www.stereophile.com/content/measuring-loudspeakers-part-three-page-2

II am still waiting for Frank Dernie to design you a proper F1 performance boom.

I am still using the flush-mounted microphone but I am sure that anything Frank designs will be a lot less kludgy-looking that what you can see at https://www.stereophile.com/content/gods-anechoic-chamber

John Atkinson
Technical Editor, Stereophile

 

[JustJones]

When I started using MLSSA to measure loudspeakers, I examined the difference between the farfield response of an LS3/5a with the microphone mounted with a conventional clip and boom stand with it flush-mounted at the end of a long copper pipe. You can see the effect of the reflections from the conventional stand in fig.23 at https://www.stereophile.com/content/measuring-loudspeakers-part-three-page-2



I am still using the flush-mounted microphone but I am sure that anything Frank designs will be a lot less kludgy-looking that what you can see at https://www.stereophile.com/content/gods-anechoic-chamber

John Atkinson
Technical Editor, Stereophile

Ha, great counterweight.

 

[napilopez]

While acknowledging that distortion is a technical weak point, and it's fine to investigate the cause, the irony about the distortion commentary to me is that it's the lower mids and bass specifically --the region with the most distortion -- that stood out when actually listening to this speaker. That, to my audio memory (and written notes) sounded better than any speaker + dual subs combination I've listened to. Something about the cardioid directivity and specially timed rear wall bounce from the subs, methinks. It just sounded so clean.

Every once in a while I want to reach out to Martijn again to try out the 8C and see if it was all just in my head Hard to know how much of it is just the cardioid aspect, not having heard any other speakers cardioid to so low. But I suspect I just like constant directivity designs. Probably part of the reason why I liked the L100 Classic so much too. Despite a flaw frequency response, the wide baffle keeps the directivity constant to pretty low (plus pretty wide directivity in the highs).

For what's happening above 2kHz, there are plenty of other speakers I'd trade with the 8C (as many of y'all know, I prefer wider directivity). The 8C is about as good as it gets in FR and Directivity in this regard, but also far from the only good speaker in this regard.

 

[phoenixdogfan]

Apologize to have being politically incorrect ... I edited the post since I realize It was misunderstood.
thanks

Never a suggestion I am aware of that either Erin or Amir receives discounted review equipment or wants to.

 

[Ericglo]

When I started using MLSSA to measure loudspeakers, I examined the difference between the farfield response of an LS3/5a with the microphone mounted with a conventional clip and boom stand with it flush-mounted at the end of a long copper pipe. You can see the effect of the reflections from the conventional stand in fig.23 at https://www.stereophile.com/content/measuring-loudspeakers-part-three-page-2



I am still using the flush-mounted microphone but I am sure that anything Frank designs will be a lot less kludgy-looking that what you can see at https://www.stereophile.com/content/gods-anechoic-chamber

John Atkinson
Technical Editor, Stereophile

I think Erin mentioned both you and Troels as the impetus to look into the boom.

If we keep badgering Frank, then maybe he will design an elegant boom for a more civilized Klippel.

 

[hardisj]

I think Erin mentioned both you and Troels as the impetus to look into the boom.

Just Troels. I didn't know JA had discussed this anywhere before. I know I see it comes up every couple years when someone starts measuring; everyone references Troels' and I'm sure JA's as well.

 

[levimax]

If I am not mistaken, the drivers used in the 8C are the following ones or some variants of them :

Tweeter : Seas H1147-06 27TBC/G

Great review and great speaker engineering. As an occasional DIY speaker builder I don't understand how they can cross a rather standard tweeter at 1250 Hz and have it play 106 dB and not have issues. Part of the great directivity is that a 1" dome tweeter is playing from 1250 up. Thanks for any help understand how this can work.

 

[617]

Great review and great speaker engineering. As an occasional DIY speaker builder I don't understand how they can cross a rather standard tweeter at 1250 Hz and have it play 106 dB and not have issues. Part of the great directivity is that a 1" dome tweeter is playing from 1250 up. Thanks for any help understand how this can work.

The tweeter is loaded into a horn, which essentially allows it to play louder into a more restricted angular space. Also, I wouldn't assume that is a standard seas tweeter, might be a lower Fs version or something. Waveguide loading a dome tweeter gives you a huge efficiency boost, around 5 or 6 db, at the low end.

 

[yourmando]

That, to my audio memory (and written notes) sounded better than any speaker + dual subs combination I've listened to. Something about the cardioid directivity and specially timed rear wall bounce form the subs, methinks. It just sounded so clean.

First, thank you @hardisj for this awesome review. You seem to have mastered the NFS in record time. No doubt your many years of testing with Klippel the “hard way” helped.

I’d be interested to hear more from folks who have heard cardioid speakers like D&D as well as more conventional dispersion active monitors that measure well like Genelecs & Neumanns.

Are the differences that you can hear mainly minor differences in the stellar frequency response of each?

Or is the audible difference characterized by something else? If so, how would that difference show up in measurements?
For example, would the difference mainly show up in a cleaner waterfall with less ringing in the bass for the cardioid speakers?

I do understand that the cardioid speakers like D&D are less sensitive to the room.

Finally, I’m curious if the more conventional Genelec or Neumann + a properly tuned subwoofer array would compare? It is definitely possible to get a really even FR even down to low bass with a subwoofer array with conventional Omni subs.

Let’s say we have proper room correction w/ multiple subs and a superb in-room response—does this close the gap would the cardioid speakers, or do the latter still sound “cleaner” due to exciting the room in a different way?

 

[hardisj]

Video review is now up. Yes, it's a long video. But so be it. This isn't a cheap speaker you can talk about in two sentences. I hope you guys enjoy and appreciate the time I put in to this.