Will consumers buy the Dutch & Dutch 8C?

[Juhazi]

Cardioid and dipole have poor efficiency down low. The size of 8c is a compromise and 80-100hz difference is not that great, and it is transition zone. Look at it's distortion above 100Hz!

Yes Californian houses and rooms are easier than Scandinavian or the apartments in central Europe or other densely populated cities. I don't see 8c as the universally best speaker in the world, but a serious alternative and a masterpiece. I haven't heard them but followed the first steps at diyaudio.com forum.

Genelec's speakers of similar size have lower but as smooth DI. The difference is at 100-2000Hz. Genelec's have protection circuit below bass tuning and don't go as low as the sealed 8c.

 

[Sergei]

What do passive radiators have to do with achieving a cardioid radiation field?

The math for a passive radiator is applicable to an open port and a solid wall as well: just set the stiffness of suspension and mass of the radiator to zero to get the open port, and set the stiffness or mass to infinity to get the solid wall. So, a speaker with passive radiator(s) behaves similarly to a speaker with open port(s) installed in the same locations, albeit the radiators allow additional tuning parameters compared to open port.

Take, for instance JBL Boombox, which uses two passive radiators on its sides:

Doesn't it resemble two 8C mid-woofer+tweeter sections put together? The Boombox generates a similar dispersion pattern: in bluetooth speakers parlance it is called "wide sound field".

As to the originality of the "cardioid pattern", I like the quote from
https://www.stereophile.com/floorloudspeakers/gradient_helsinki_15_loudspeaker/index.html:
"A clever engineer with an interest in home audio says that the real obstacle to high-fidelity sound is the adverse and unpredictable way in which speakers interact with most domestic rooms. To address that need, he brings to market a loudspeaker that disperses sound in a new and original way. Controversy ensues. Controversy endures."

The article above refers to Bose 901 as yet another example of a speaker with non-traditional radiation field. A quote from
"http://noaudiophile.com/Bose_901/":
"One full range driver in the front, 8 on the back, 4 port tubes, and an active EQ box to make it sound reasonable. This is the speaker that back in 1968 proved commercial viability of omnidirectional, dipole, and all sorts of bizarre dispersion patterns ... Imaging is huge and involved".

A pair of 8Cs uses a more balanced scheme: 4 drivers in the front, 4 on the back - 50 years of progress! Still, just like Bose 901, it resorts to 4 ports and "an active EQ box"

 

[Wombat]

We have some consumers on ASR who have purchased them.

 

[Purité Audio]

The math for a passive radiator is applicable to an open port and a solid wall as well: just set the stiffness of suspension and mass of the radiator to zero to get the open port, and set the stiffness or mass to infinity to get the solid wall. So, a speaker with passive radiator(s) behaves similarly to a speaker with open port(s) installed in the same locations, albeit the radiators allow additional tuning parameters compared to open port.

Take, for instance JBL Boombox, which uses two passive radiators on its sides:

Doesn't it resemble two 8C mid-woofer+tweeter sections put together? The Boombox generates a similar dispersion pattern: in bluetooth speakers parlance it is called "wide sound field".

As to the originality of the "cardioid pattern", I like the quote from
https://www.stereophile.com/floorloudspeakers/gradient_helsinki_15_loudspeaker/index.html:
"A clever engineer with an interest in home audio says that the real obstacle to high-fidelity sound is the adverse and unpredictable way in which speakers interact with most domestic rooms. To address that need, he brings to market a loudspeaker that disperses sound in a new and original way. Controversy ensues. Controversy endures."

The article above refers to Bose 901 as yet another example of a speaker with non-traditional radiation field. A quote from
"http://noaudiophile.com/Bose_901/":
"One full range driver in the front, 8 on the back, 4 port tubes, and an active EQ box to make it sound reasonable. This is the speaker that back in 1968 proved commercial viability of omnidirectional, dipole, and all sorts of bizarre dispersion patterns ... Imaging is huge and involved".

A pair of 8Cs uses a more balanced scheme: 4 drivers in the front, 4 on the back - 50 years of progress! Still, just like Bose 901, it resorts to 4 ports and "an active EQ box"

I have Gradient’s new 1,4 passive loudspeakers here, they are super, cardioid ,coaxial really good bass, just a sensible design and not too expensive, they are my favourite passive loudspeaker.
Keith

 

[dc655321]

The math for a passive radiator is applicable to an open port and a solid wall as well: just set the stiffness of suspension and mass of the radiator to zero to get the open port, and set the stiffness or mass to infinity to get the solid wall. So, a speaker with passive radiator(s) behaves similarly to a speaker with open port(s) installed in the same locations, albeit the radiators allow additional tuning parameters compared to open port.

Take, for instance JBL Boombox, which uses two passive radiators on its sides:

Doesn't it resemble two 8C mid-woofer+tweeter sections put together? The Boombox generates a similar dispersion pattern: in bluetooth speakers parlance it is called "wide sound field".

As to the originality of the "cardioid pattern", I like the quote from
https://www.stereophile.com/floorloudspeakers/gradient_helsinki_15_loudspeaker/index.html:
"A clever engineer with an interest in home audio says that the real obstacle to high-fidelity sound is the adverse and unpredictable way in which speakers interact with most domestic rooms. To address that need, he brings to market a loudspeaker that disperses sound in a new and original way. Controversy ensues. Controversy endures."

The article above refers to Bose 901 as yet another example of a speaker with non-traditional radiation field. A quote from
"http://noaudiophile.com/Bose_901/":
"One full range driver in the front, 8 on the back, 4 port tubes, and an active EQ box to make it sound reasonable. This is the speaker that back in 1968 proved commercial viability of omnidirectional, dipole, and all sorts of bizarre dispersion patterns ... Imaging is huge and involved".

A pair of 8Cs uses a more balanced scheme: 4 drivers in the front, 4 on the back - 50 years of progress! Still, just like Bose 901, it resorts to 4 ports and "an active EQ box"

I've not seen any claims that the design principles of the 8C are absolutely original. But that doesn't make them ineffective, only atypical.
Perhaps I'm misunderstanding what you're trying to convey, though.

Similarity of the D&D 8C to the Bose 901 is superficial at best.
A cursory read through your link (thanks for that) indicates nothing intentionally cardioid about the 901.
Indeed, it is difficult to ascertain what, if any, principles the acoustic system of the 901 was targeted at.
Omni-directionality?

Achieving a cardioid radiation pattern can be done in a number of ways, but three attributes are necessary:
1) a source 180 degrees out of phase with the primary
2) amplitude matching between in and out-of-phase sources over some range of frequencies
3) a delay between sources

A passive radiator configuration can provide 1) (obviously), and geometry could provide 3).
But would the energy required and absorbed to passively drive the radiators not rule out 2), at least over a practically useful range?

 

[PierreV]

I still own a pair of non rotten Bose 901 type VI speakers. They are fun speakers and quite enjoyable if one wants background music without a defined sweet spot. But I roll my eyes when I see them compared in any way to the 8c

 

[Sergei]

I have Gradient’s new 1,4 passive loudspeakers here, they are super, cardioid ,coaxial really good bass, just a sensible design and not too expensive, they are my favourite passive loudspeaker.
Keith

At $6,500/pair, how are they going to compete with ELAC Navis? https://www.elac.com/series/navis-powered-speakers/

It happened. Game is mostly over for boutique speakers manufacturers. Today one can buy a reasonably priced consumer version of a decent 3-way studio monitor. Marketing and distribution channels are primed up:

http://trueaudiophile.com/elac-navis-wireless-bookshelf-speaker-by-andrew-jones-new/ ~$2,000/pair
http://trueaudiophile.com/elac-navis-wireless-floorstanding-speaker-andrew-jones-new/ ~$4,000/pair

The point of no return was mass-market distributors joining the game:
https://www.crutchfield.com/p_970NAVISEE/ELAC-Navis-ARB-51-Gloss-Ebony-Emara.html?tp=72535
Note: this particular color variation of Navis ARB-51 is sold out at Crutchfield. How often do you see that with other speakers?

 

[Sergei]

2) amplitude matching between in and out-of-phase sources over some range of frequencies

But would the energy required and absorbed to passively drive the radiators not rule out 2), at least over a practically useful range?

This is a very good question. I tried to find objective measurements of some of the best-selling bluetooth speakers, yet came up short.

The "objective measurements" are done differently these days: via Youtube. For instance:

Traditional metrics are sparse in these videos. Yet one can tell that the energy that drives the radiators appears to be significant:

 

[Dialectic]

Finger getting itchy on ignore button...

 

[dc655321]

This is a very good question. I tried to find objective measurements of some of the best-selling bluetooth speakers, yet came up short.

The "objective measurements" are done differently these days: via Youtube. For instance:

Traditional metrics are sparse in these videos. Yet one can tell that the energy that drives the radiators appears to be significant:

AFAICT, passive radiators in these applications have the same role as in full-sized applications - frequency response extension, not radiation field contouring.

There is simply no space available for an effectively sized port. Hence, passive radiators are "required" to achieve some low-end FR target.

 

[boXem]

Achieving a cardioid radiation pattern can be done in a number of ways, but three attributes are necessary:
1) a source 180 degrees out of phase with the primary
2) amplitude matching between in and out-of-phase sources over some range of frequencies
3) a delay between sources

If I remember well, LX mini achieves a cardioid pattern with the simple summation of a dipole and a monopole. DSP is only used to equalize the dipole.

 

[Sergei]

AFAICT, passive radiators in these applications have the same role as in full-sized applications - frequency response extension, not radiation field contouring.

There is simply no space available for an effectively sized port. Hence, passive radiators are "required" to achieve some low-end FR target.

I wouldn't be so sure that the LF extension is the only goal of such design. Radiation field contouring is very important for the bluetooth speakers used outdoors in the presence of neighbors.

Last Wednesday night, I happened to stroll on a pier in Long Beach, California. Apparently "the thing" down there is night fishing using glowing baits, while listening to hip-hop and similar music on large bluetooth speakers, some of them with illumination pulsating in sync with the beats.

The speakers were darn directional: there were at least half a dozen of them on the pier, and walking by them proved the presence of directivity rather convincingly. The directivity was greatly helping the neighboring fishermen enjoy their own music.

 

[Sergei]

I've not seen any claims that the design principles of the 8C are absolutely original. But that doesn't make them ineffective, only atypical.

In my opinion, such design makes 8C less effective as a studio monitor.

For instance, compare the horizontal frequency response depicted on the last page of
https://dutchdutch.com/wp-content/uploads/2018/11/8c-Spec-Sheet-2019.pdf
with the horizontal directivity polar plot of Genelec 8351A at
https://www.princeton.edu/3D3A/Dire...ots/Horizontal/Genelec 8351A H Polar Plot.png.

At 45 degrees, Genelec keeps the power of all reproduced frequencies within 3 dB. 8C, more like within 6 dB.

This is the inherent tradeoff of the "cardioid" pattern achieved via passive design elements. Perhaps better illustrated by comparison of the Genelec vs Gradient 1.5 polar plots, borrowed from the Princeton site.

You can see that Genelec is designed with the goal of having as uniform frequency response as possible at angles more narrow than +-45 degrees. The assumption is that the rest of radiation is absorbed by a well-acoustically-treated room.

Gradient, on the other hand, sacrifices such accuracy in exchange for reduced reflections in an acoustically-untreated room. As I mentioned before, this could be a sensible tradeoff in certain urban settings. Since I'm not an urban-dwelling hot blond, 8C doesn't interest me much

 

[restorer-john]

passive radiators in these applications have the same role as in full-sized applications

To keep the water out when you put them in the pool?

 

[Daverz]

If I remember well, LX mini achieves a cardioid pattern with the simple summation of a dipole and a monopole. DSP is only used to equalize the dipole.

For a while there, I thought you were referring to the KEF LSX, but this must be one of the Linkwitz kits?

 

[Dialectic]

For a while there, I thought you were referring to the KEF LSX, but this must be one of the Linkwitz kits?

Yessir, it's the one with PVC pipes. I've never heard it. Very much want to, but the appearance is a domestic nonstarter for me.

 

[Xulonn]

In my occasional Google Image searches, I have been amazed at the incredible variety of loudspeaker designs out there, and some of the Gradient models certainly fit in the exotic category...

 

[boXem]

Yessir, it's the one with PVC pipes. I've never heard it. Very much want to, but the appearance is a domestic nonstarter for me.

Exactly.
Concerning the plumber style, there is a tentative to improve it with the commercial version.
https://www.magiclx521.com/epages/17940394.sf/en_GB/?ObjectPath=/Shops/17940394/Products/LXsirius
The main difficulty is how to handle the upward facing low-mid.

 

[Juhazi]

And I have made dsp-active clones of both Gradient 1.3 and 1.4 !

NRC directivity plots start at 500Hz, but cardioid mid and bass are below that. 1.3 and 1.4 have omnipole downfire bass, xo around 200Hz. 1.5 has dipole bass and cardioid mid. This place isn't right to tell everything about them, they all have different radiation patterns. If someone wants to read more, go to diyaudio.com and find threads started by Juhazi.

 

[dc655321]

I wouldn't be so sure that the LF extension is the only goal of such design. Radiation field contouring is very important for the bluetooth speakers used outdoors in the presence of neighbors.

Oh I'm not at all "so sure". However, I am generally skeptical when presented with information that doesn't make physical sense.
And I found nothing in those video clips about the JBL system that indicates directivity was a design goal, only low frequency response.

Last Wednesday night, I happened to stroll on a pier in Long Beach, California. Apparently "the thing" down there is night fishing using glowing baits, while listening to hip-hop and similar music on large bluetooth speakers, some of them with illumination pulsating in sync with the beats.

The speakers were darn directional: there were at least half a dozen of them on the pier, and walking by them proved the presence of directivity rather convincingly. The directivity was greatly helping the neighboring fishermen enjoy their own music.

Anecdotal, ear-based measurement?
By that description, a car driving down the street with beats blasting is "directional" too.

In my opinion, such design makes 8C less effective as a studio monitor.

For instance, compare the horizontal frequency response depicted on the last page of
https://dutchdutch.com/wp-content/uploads/2018/11/8c-Spec-Sheet-2019.pdf
with the horizontal directivity polar plot of Genelec 8351A at
https://www.princeton.edu/3D3A/Dire...ots/Horizontal/Genelec 8351A H Polar Plot.png.

At 45 degrees, Genelec keeps the power of all reproduced frequencies within 3 dB. 8C, more like within 6 dB.

This is the inherent tradeoff of the "cardioid" pattern achieved via passive design elements. Perhaps better illustrated by comparison of the Genelec vs Gradient 1.5 polar plots, borrowed from the Princeton site.

You can see that Genelec is designed with the goal of having as uniform frequency response as possible at angles more narrow than +-45 degrees. The assumption is that the rest of radiation is absorbed by a well-acoustically-treated room.

Gradient, on the other hand, sacrifices such accuracy in exchange for reduced reflections in an acoustically-untreated room. As I mentioned before, this could be a sensible tradeoff in certain urban settings. Since I'm not an urban-dwelling hot blond, 8C doesn't interest me much

What exactly is it about the design of the 8C that makes it "less effective as a studio monitor"?
I'm having a hard time getting from great measurements, to "less effective"...

From your sources, above:

8C

Genelec 8351A