Dutch & Dutch 8Cs

[svart-hvitt]

If we are to have good discussions on audio gear, both their pros and cons should be highlighted. Needless to say, the discussion should be fact based; listening impressions and personal experiences could also count, but subjectivism is only of interest if the writer knows how to balance his review.

When a professional dealer manages to get only 40-45 Hz out of a speaker which is specified below 30 Hz, it is certainly of interest; because the dealer is then either incompetent or he is misrepresenting.

Everyone has the right to get a bit "enthusiastic". Even @Floyd Toole gets a bit enthusiastic (about his research) sometimes, but he has every right to be enthusiastic given his great contributions to our understanding of audio in practice, in our daily lives! And I sort of like Floyd's perspective on speakers: If the specifications are trustworthy (some producers detail specs that are trustworthy, some don't), you can read - more or less - out of the specifications what a speaker will sound like. Boring, but true in my book.

To my astonishment - because that is not what you are led to believe by many reviewers - competently designed speakers with similar specifications sound about the same. Dispersion characteristics may be the biggest source of "different sound"? So I don't understand the excitement of some reviewers. One of the more interesting specifications in speaker design is, in my view, its volume (in litres, for example). My experience tells me that bigger volume sounds different than a smaller volume speaker. And when you think about it, why should a competent engineer be able to produce significantly better sound if he has only 1/3 or 1/4 of the volume to play with? Volume of a competently designed speaker may be its most important constraint, right?

Sometimes, a new design heralds a new paradigm. But there are more news of paradigms than real paradigms. So a science-oriented audio enthusiast will always be a bit skeptical to claims of a paradigm shift.

We have just recently had one such example, where news of a paradigm shift was replaced by more down-to-earth news (literally speaking). The Kii Three speakers were marketed as "small size, big sound", as an alternative to existing full-range bigger speakers etc. Marketing was used to make people believe that the laws of physics were defied. And people jumped on. Despite the fact that Kii themselves, suddenly, changed the specifications to 30 Hz low frequency capacity from 20 Hz capacity in the low frequencies. 10 Hz disappeared over night. Internet forums were still full of praise, and it was almost impossible to find balanced reports and reviews. Despite the fact that, for example, the Kii cabinet was clearly vibrating/resonating (easily felt by anyone who placed his hand on the cabinet), which cannot be a positive for speakers to produce neutral sound.

Fast forward to May 2018 and Kii come to the market with a bass tower for the Kii Threes to be placed on. Suddenly, the small speakers triple in size. And nobody questions the previous rhetoric of Kii. The lack of memory and critical reasoning on internet forums make you think of the sheep of "Nineteen Eighty-Four". Why triple the footprint and more than doubling the price of the product if the Kiis were "big sound", "full-range" all the time?

And I still haven't seen any documentation that the Kiis manage a frequency response accuracy of +/- 0.5 dB. Has anyone ever seen documentation of a speaker with a 0.5 dB accuracy (or lower)?

This was not meant to be a Kii report, just a reflection on the need to report about both positives and deficiencies of products. Science is always balanced, per definition. Because marketing is good at focusing on the positives, I think - subjectively! - that ASR members should be good at discussing the weaknesses of a design as well, in order to have a good grasp on which problems were solved in a new product and which problems that still are to be resolved in the future.

DSP and computer assisted design mean that the audio enthusiast of modern times faces a bright future. But we don't need to exaggerate the positives and downplay the negatives on the way to a better audio future.

Just my 2 cents. I am sorry the text got so long.

 

[dallasjustice]

If the room is rectangular symmetric placement across width and along length does cancel the odd order axial modes along those

The Welti so called cancellation is only a matter of degree. For example, the midwall subs placed on the sidewalls of a rectangular room are actually in the antimode position for the 1st axial length mode (1,0,0). Therefore, those subs will not excite that mode at all. (Mode cancellation). BUT there are two additional subs on the front and back walls at midwall. Those subs will excite the 1,0,0. The net effect is that the 1,0,0 is reduced and widened out. It is correct to say that the Welti midwall setup is easier to EQ and there’s a wider sweet spot.

 

[Kal Rubinson]

sorry, but if I put 10k in a pair of speakers I want to know where I'm going, I want to know if it really holds up? if the company closes one day...who will take care of the dsp updates? who will repair it if the electronics (with proprietary circuitry) fails?
I don't think I'm the only one asking myself those questions??

This is a real issue. Complex integrated devices with fundamental dependence on software, such as these speakers, it is unlikely that any agent other than the manufacturer can fully support them. So, being able to project that the manufacturer will exist for the foreseeable future is essential.

 

[Dialectic]

This is a real issue. Complex integrated devices with fundamental dependence on software, such as these speakers, it is unlikely that any agent other than the manufacturer can fully support them. So, being able to project that the manufacturer will exist for the foreseeable future is essential.

Agreed. I hope D&D produces a native, non-web-based app to give us current users assurance that we will be able to adjust the 8Cs' internal settings well into the future.

 

[Sal1950]

Enthusiastic debate is fun to both read and participate in.
But let's remember to remain civil in the process.

 

[Sal1950]

DSP and computer assisted design mean that the audio enthusiast of modern times faces a bright future. But we don't need to exaggerate the positives and downplay the negatives on the way to a better audio future.

Good post. I've been around this hobby for over half a century now and won't even begin to think about the times I've heard the "all else is gaslight" "paradigm shift" claims for new products.. A few have been genuine improvements but most all have shortly been replaced with the next big thing. I'm sure the Kii's and D&D's are excellent sounding "small" speakers with modern tech making them all (or near all) they can be. But you can never change the laws of physics and the fact that limitations of driver area and cone excursion will have it's hold on what's possible.

 

[svart-hvitt]

Enthusiastic debate is fun to both read and participate in.
But let's remember to remain civil in the process.

OK, let’s call it «strategic misrepresentation» instead. So we can have a debate on what’s «strategic misrepresentation» and what’s «tactical misrepresentation».



Or we could call a spade a spade.

In science, though, I believe «misrepresentation»is the politically correct term:

http://eureka.sbs.ox.ac.uk/717/

Or: http://eureka.sbs.ox.ac.uk/4662/1/F...ericanPlanningAssociationCites0(2013June).pdf

Quote: «And if underestimation is deliberate then it is lying, which is unethical by any code of conduct and unlawful in many jurisdictions for this type of issue (Bok 1979, Cliffe et al. 2000, Wachs 1989).10 Such bad planning and unethical behavior place citizens, taxpayers, investors, and other stakeholders in public projects at a risk that is deliberately hidden from them».

 

[Dialectic]

@Thomas savage can the Genelec debate be moved to a separate thread?

 

[svart-hvitt]

Good post. I've been around this hobby for over half a century now and won't even begin to think about the times I've heard the "all else is gaslight" "paradigm shift" claims for new products.. A few have been genuine improvements but most all have shortly been replaced with the next big thing. I'm sure the Kii's and D&D's are excellent sounding "small" speakers with modern tech making them all (or near all) they can be. But you can never change the laws of physics and the fact that limitations of driver area and cone excursion will have it's hold on what's possible.

After I heard a friend’s setup, implementing no less than 12 times 24 inch subs, I have never really been convinced that size doesn’t matter. I wouldn’t call his sound the pinnacle of neutrality (because I don’t know what’s neutrality at this level), but with nice DSP etc. it sounded like nothing I’ve ever heard.

(I could hear, among other things, very clearly, how my high-quality vinyl ripped files sounded shallow as if resolution was seriously lacking. A freak mad professor setup!)

 

[JohnPM]

The Welti so called cancellation is only a matter of degree. For example, the midwall subs placed on the sidewalls of a rectangular room are actually in the antimode position for the 1st axial length mode (1,0,0). Therefore, those subs will not excite that mode at all. (Mode cancellation). BUT there are two additional subs on the front and back walls at midwall. Those subs will excite the 1,0,0. The net effect is that the 1,0,0 is reduced and widened out.

The front and back subs in midwall placement are responsible for killing the 1st length mode (and the other odd order length modes). Symmetric placement along an axis kills odd order axial modes because they in effect get excited in antiphase at the two positions so the net effect is no excitation. If there's any residual excitation of those modes the most likely culprit is differences in the outputs of the front and back subs - it only takes a slight difference to disrupt the cancellation, a dB of gain difference or a 1 Hz difference in LF extension between the two is sufficient for the modes to reappear in measurements, albeit at lower levels commensurate with the partial cancellation that then occurs. Midwall placement is more sensitive to differences in the subs than corner placement, and the positional variation is also greater for midwall than corners. To see the kind of perfect cancellation that simulations predict does require identically performing subs, so real world attempts to replicate that face challenges.

 

[Purité Audio]

Good post. I've been around this hobby for over half a century now and won't even begin to think about the times I've heard the "all else is gaslight" "paradigm shift" claims for new products.. A few have been genuine improvements but most all have shortly been replaced with the next big thing. I'm sure the Kii's and D&D's are excellent sounding "small" speakers with modern tech making them all (or near all) they can be. But you can never change the laws of physics and the fact that limitations of driver area and cone excursion will have it's hold on what's possible.

You have actually glanced at the specs of the 8C have you Sal?
Keith

 

[Purité Audio]

OK, let’s call it «strategic misrepresentation» instead. So we can have a debate on what’s «strategic misrepresentation» and what’s «tactical misrepresentation».



Or we could call a spade a spade.

In science, though, I believe «misrepresentation»is the politically correct term:

http://eureka.sbs.ox.ac.uk/717/

Or: http://eureka.sbs.ox.ac.uk/4662/1/Flyvbjerg13HowPlannersDealWithUncomfortableKnowledgetheDubiousEthicsoftheAmericanPlanningAssociationCites0(2013June).pdf

Quote: «And if underestimation is deliberate then it is lying, which is unethical by any code of conduct and unlawful in many jurisdictions for this type of issue (Bok 1979, Cliffe et al. 2000, Wachs 1989).10 Such bad planning and unethical behavior place citizens, taxpayers, investors, and other stakeholders in public projects at a risk that is deliberately hidden from them».

https://www.community.genelec.com/forum/-/message_boards/message/933654
Thanks for your post and interesting questions.

The original ribbon tweeter used in Genelec S30 is based on the 50’s Decca ribbon. From the start Genelec bought ribbon drivers and modified them, basically using only magnet and chassis pot as components. The ribbon itself, its careful corrugation and assembly and its matching transformer are Genelec designs. In the S30B we added a short waveguide in front of the ribbon, and in the S30C and D models we used a combined front baffle with the midrange driver.

Also, our flagship 5" midrange design, introduced in 1989 in the large 1035A three-way main monitor, is a proprietary Genelec design featured nowadays in all our 3-way models and manufactured in-house.

In addition to our own design and manufacturing, Genelec benefits also from the latest advances in driver developments by collaborating closely with a selection of leading driver manufacturers who are specialized in manufacturing high-end tailored made drivers. Genelec’s tailored made drivers are manufactured according to our proprietary design specifications and requirements as well as quality and test criteria. The final quality of the tailored made drivers is assured by Genelec via thorough testing both in the manufacturer’s site and in Genelec’s factory, to fit seamlessly to our system solutions.

Concerning your question about soft dome tweeters, Genelec has been using such tweeter types in many early models such as the 1019A and 1022B, as well as in the 1024 series and large 1025 series main monitors. For further infos on these discontinued models, please consult our website under: http://www.genelec.com/products/previous-models/

In general, dome tweeters are fairly efficient, and have low distortion and wide dispersion. There is a choice between hard and soft dome materials, but all have relatively low mass and good power handling capabilities.

Soft dome on-axis response can go flat easily over 20 kHz. As the material is soft, the dome does not vibrate as a piston – the first breakup modes are already present at a few kHz - but a bending wave propagates along the material to the center of the dome and back. At certain frequencies the center of the dome vibrates in anti-phase with respect to the voice coil. To control the vibration the soft dome is damped with viscous material and it absorbs the wave. At higher frequencies the soft dome becomes a ring radiator where the main radiation happens from a narrow area around the voice coil; i.e. both dome and surround radiate. This means that the off-axis response starts to drop soon above 10 kHz with a 25 mm dome, and this is visible in the power response. Several years go Vifa made a new soft dome tweeter, where they omitted the dome totally and made it a bare ring radiator. The diaphragm was supported from the center giving a distinctive look to this driver. Its on-axis response went to about 40 kHz but off-axis response dropped rapidly as it became directional.

Hard domes vibrate as a piston up to the first breakup frequency, which depends on dome material and size. The same physics works with hard domes as with soft domes, but as the speed of sound in a hard material is much higher than in a soft one, the first breakup frequency is typically around 25...26 kHz for a 25 mm aluminum or titanium dome and around 28..35 kHz for a 19 mm aluminum or titanium dome. Titanium is stiffer than aluminum, but as it is also heavier, the end result is practically the same. Beryllium dome breakups are higher.

Hard dome present also a greater power handling and maximum SPL output. Their dispersion characteristic allows a very efficient combination with a DCW waveguide which shapes the emitted wavefront in a controllable way, thus allowing control of the dispersion. Such DCW curved, rigid surface fitted in front of the driver unit can be dimensioned for constant directivity and may also extend down to low mid frequencies depending on the DCW frontal area.

A properly engineered hard dome tweeter can have extremely low distortions, good power handling, good directivity and it can be very reliable. All these parameters are objective reasons for our choice of hard dome tweeters.

Keith

 

[Sal1950]

You have actually glanced at the specs of the 8C have you Sal?
Keith

Yes, but what's your point?

 

[Dialectic]

Now that the issue of reliability has been raised, it's time to report on a few problems with my 8Cs and Dutch & Dutch's helpful responses:

1. My left 8C had a small visible line in the lower left part of the cabinet when I first got it. This line grew into a full fledged crack going all the way through the lower left cabinet up to the speaker's left vent. The right speaker came with a slightly bent back panel that is not flush with the cabinet. I heard from another 8C user about a cabinet imperfection, so this issue is perhaps not isolated to my pair. Dutch & Dutch and Purite Audio were very responsive about the cabinet problems and have kindly shipped a replacement pair of 8Cs, which I will receive this week.
   
2. When entering EQ filters, I encountered a software problem that caused one of my 8Cs to become unusable. The speaker could be switched on but would not produce sound. Dutch & Dutch was very responsive, logging into the speaker and correcting the software problem, which probably has been fixed in the new firmware.
   
3. As of this evening, the rear woofers on my right 8C make a powerful thump when the speaker is switched on. I never heard such a thump before this evening and have repeated it three times. My left 8C does not thump when turned on.

I'm not doing anything unusual with the 8Cs except using them with BACCH. They are in a climate-controlled apartment. I enjoy the way the 8Cs sound, but it's clear that the bleeding edge has its perils.

Kudos to Dutch & Dutch for their honesty and courtesy in fixing problems 1 and 2. I'm not concerned about problem 3 now because I'm getting a replacement pair of 8Cs this week.

 

[oivavoi]

Being that "other user", I can confirm this. When my pair arrived to the distributor, he noticed some slight irregularities on the back of the cabinets. He didn't want to take any chances, and therefore promptly asked D&D to send him a new pair, which they agreed to straight away. So I will keep my current pair until the new pair arrives, and then send my existing pair back.

It does seem like D&D has had some difficulties with production in this initial phase. On the positive side, they seem to take complete responsibility, and do fix the issues that arise.

 

[Wombat]

Being that "other user", I can confirm this. When my pair arrived to the distributor, he noticed some slight irregularities on the back of the cabinets. He didn't want to take any chances, and therefore promptly asked D&D to send him a new pair, which they agreed too straight away. So I will keep my current pair until the new pair arrives, and then send my existing pair back.

It does seem like D&D has had some difficulties with production in this initial phase. On the positive side, they seem to take complete responsibility, and do fix the issues that arise.

Sounds like they need a quality management system in place to catch problems before products are despatched. At their product price-point these occurrences do not look good. Product replacement alone does not allay the disappointment and inconvenience experienced by the customer.

 

[Liberal Democracy]

@Thomas savage can the Genelec debate be moved to a separate thread?

Send me the post numbers you want moved, I know there was a diversion into subwoofer setup too.

 

[oivavoi]

Send me the post numbers you want moved, I know there was a diversion into subwoofer setup too.

I would argue that thoughts about subwoofer setup actually is relevant in this thread, given that subwoofer connectivity is one of the selling points of the 8Cs (at least as long as the topic doesn't completely overtake the thread). Or what say you, fellow traveller in the land of Dutchophilia @soundArgument ?

 

[Liberal Democracy]

Now that the issue of reliability has been raised, it's time to report on a few problems with my 8Cs and Dutch & Dutch's helpful responses:

1. My left 8C had a small visible line in the lower left part of the cabinet when I first got it. This line grew into a full fledged crack going all the way through the lower left cabinet up to the speaker's left vent. The right speaker came with a slightly bent back panel that is not flush with the cabinet. I heard from another 8C user about a cabinet imperfection, so this issue is perhaps not isolated to my pair. Dutch & Dutch and Purite Audio were very responsive about the cabinet problems and have kindly shipped a replacement pair of 8Cs, which I will receive this week.
   
2. When entering EQ filters, I encountered a software problem that caused one of my 8Cs to become unusable. The speaker could be switched on but would not produce sound. Dutch & Dutch was very responsive, logging into the speaker and correcting the software problem, which probably has been fixed in the new firmware.
   
3. As of this evening, the rear woofers on my right 8C make a powerful thump when the speaker is switched on. I never heard such a thump before this evening and have repeated it three times. My left 8C does not thump when turned on.

I'm not doing anything unusual with the 8Cs except using them with BACCH. They are in a climate-controlled apartment. I enjoy the way the 8Cs sound, but it's clear that the bleeding edge has its perils.

Kudos to Dutch & Dutch for their honesty and courtesy in fixing problems 1 and 2. I'm not concerned about problem 3 now because I'm getting a replacement pair of 8Cs this week.

All totally unacceptable imo I’m glad they are replacing them but I would have zero confidence in them . I have been down this road myself so you have my sympathies.

I hope the new pair are right and you get years of enjoyment out of them.

 

[Liberal Democracy]

I would argue that thoughts about subwoofer setup actually is relevant in this thread, given that subwoofer connectivity is one of the selling points of the 8Cs (at least as long as the topic doesn't completely overtake the thread). Or what say you, fellow traveller in the land of Dutchophilia @soundArgument ?

I thought so which is why I asked for the post numbers so I don’t take out the Wrong things.