Dutch & Dutch 15C Discussion

[Satanica]

The thing is, once glm comes into play it won't make a difference, and the imaging of the 8381a's gonna be unbeatable.
It'd be crazy to be able to make a double blind test with these 2 and verify that theory, I'd be ready to pay for this (not 200k€ though).

Maybe, the 8381A doesn't appear to be a constant directivity design which I believe is known to improve imaging.
I wouldn't be surprised if the smaller "Ones" are preferred when played within their range.

 

[Frank Dernie]

To me, the measurements provided for the Genelec 8381A makes it look somewhat inferior to the Dutch & Dutch 8C,

Dispersion maybe, distortion it is much lower FWIW

 

[Satanica]

Dispersion maybe, distortion it is much lower FWIW

Horizontal dispersion, definitely, the 8C is state of the art and ahead of all Genelecs.
It's vertical dispersion is good too, especially considering that the tweeter is quite above the mid driver.
But yes, it measures higher distortion.

 

[829]

To me, the measurements provided for the Genelec 8381A makes it look somewhat inferior to the Dutch & Dutch 8C, at least in horizontal dispersion.
It does not look as well controlled in the Genelec 8381A, there's a widening at 1kHz and it's overall horizontal directivity is not as constant.
Obviously the Genelec 8381A is in a completely different league when it comes to output and it's greater point source attribute means one can site more above or below it.
And one last thing, the 15C might not be as good as the 8C, I wonder if the 15C will ever be Klippel measured.

Integrating huge drivers like 15" towards the midrange always comes at a cost, as also seen with the JBL M2 and will not differ for D&D 15C or Genelec 8381A.

Horizontal dispersion, definitely, the 8C is state of the art and ahead of all Genelecs.
It's vertical dispersion is good too, especially considering that the tweeter is quite above the mid driver.
But yes, it measures higher distortion.

I'm not sure I can see the 8C's clear superiority compared to any Genelec's horizontal dispersion; and Genelec does not only do coaxial designs.



The 8C reaches down deeper in this comparison, but at the big loss of headroom as has been mentioned before.

 

[Satanica]

I'm not sure I can see the 8C's clear superiority compared to any Genelec's horizontal dispersion; and Genelec does not only do coaxial designs.

View attachment 530394

I think the 8361 looks a bit ragged in comparison and does not control directivity as low. It also looks a bit lean in the bass.

The 8C reaches down deeper in this comparison, but at the big loss of headroom as has been mentioned before.

And it also has a big gain in headroom due to bass coupling with less dips than typical speakers. It will almost certainly require significant EQ reduction in room adding to it's headroom. It effectively uses the rear wall as an amplifier.

I think they are both excellent speakers with some pros and cons compared to each other. I own the 8C, but I would not recommened it over the Genelec 8361A or 8351B, it would be to close to call to recommend to any individual. It depends on one's use case, room and where priorities are, etc.

 

[829]

[...] It effectively uses the rear wall as an amplifier.

I think they are both excellent speakers with some pros and cons compared to each other. I own the 8C, but I would not recommened it over the Genelec 8361A or 8351B, it would be to close to call to recommend to any individual. It depends on one's use case, room and where priorities are, etc.

One of the main points of cardioid bass is to involve the rear wall less, hence using less room gain in its working range and thus to experience smaller room modal issues as compared to a non-cardioid bass dispersion.

But yes, it comes down to personal priorities when choosing amongst any SOTA speakers like these.

 

[Karmacoma]

Maybe, the 8381A doesn't appear to be a constant directivity design which I believe is known to improve imaging.

The imaging is improved by the coaxial design, you're right in saying that constant directivity improves imaging, but the direct sound dominates in that regard, so I believe it would still perform better.

 

[Satanica]

One of the main points of cardioid bass is to involve the rear wall less, hence using less room gain in its working range and thus to experience smaller room modal issues as compared to a non-cardioid bass dispersion.

I don't think one can think of the 8C having cardioid bass, as it's omnidirectional from 100Hz and down from the rear woofers. It really has Boudary Coupled Bass (BCB), well it can have, as it's encouraged to get it as close to the rear wall as possible (10cm gap) to involve the rear wall positively as much as possible. It does have a cardioid midrange. The 15C has surely been designed with the same idea.

 

[Satanica]

The imaging is improved by the coaxial design, you're right in saying that constant directivity improves imaging, but the direct sound dominates in that regard, so I believe it would still perform better.

I agree, but I would not be surprised if the less expensive "Ones" match the 8381A or are better still.

 

[829]

I don't think one can think of the 8C having cardioid bass, as it's omnidirectional from 100Hz and down from the rear woofers. It really has Boudary Coupled Bass (BCB), well it can have, as it's encouraged to get it as close to the rear wall as possible (10cm gap) to involve the rear wall positively as much as possible. It does have a cardioid midrange. The 15C has surely been designed with the same idea.

Well, up to at least 250 Hz we still remain in the bass region where room modes dominate.

The suggestion of placing the speakers as closely as possible to a rear wall helps with reducing SBIR, see Wall Reflections and Cancellations. Speakers with bass reflex port on the rear usually require a small gap to allow for "breathing" of the port.

 

[Mort]

I doubt very much if I could A/B blind distinguish the 8381a vs 15c with music. Maybe after training a few rounds on pink noise or something.

 

[Duke]

Note that the vertical off-axis dip in the crossover region of the Dutch & Dutch designs is of academic interest only UNLESS your ears are at the height where that dippage happens.

You see, the vertical-axis dip is a LOCAL INTERFERENCE effect, so it appears ONLY where the sound waves from the woofer and waveguide pass through one another along that angle. Those sound waves then continue onward, unattenuated by having passed through one another. Sure it looks dreadful in the measurements, but this is an instance where what is actually CAUSING the anomaly in the measurements needs to be understood.

If your ears are at or near the correct height, then the comb filtering dip occuring along, and ONLY along, an angle which bypasses you entirely, and which occurs ONLY in the direct sound (and disappears entirely in the reflection field), has no audible effect.

 

[Karmacoma]

Note that the vertical off-axis dip in the crossover region of the Dutch & Dutch designs is of academic interest only UNLESS your ears are at the height where that dippage happens.

You see, the vertical-axis dip is a LOCAL INTERFERENCE effect, so it appears ONLY where the sound waves from the woofer and waveguide pass through one another along that angle. Those sound waves then continue onward, unattenuated by having passed through one another. Sure it looks dreadful in the measurements, but this is an instance where what is actually CAUSING the anomaly in the measurements needs to be understood.

If you ears are at or near the correct height, then the comb filtering dip occuring along, and ONLY along, an angle which bypasses you entirely, and which occurs ONLY in the direct sound (and disappears entirely in the reflection field), has no audible effect.

What's your take on the imaging of both speakers? We're on a ultimate speaker trip here

 

[Paul7777x]

What's your take on the imaging of both speakers? We're on a ultimate speaker trip here

An ultimate speaker indeed.

I do wonder how large a room would have to be (and ceiling height) to get the very best from what will undoubtedly be superb speakers.

 

[Paul7777x]

An ultimate speaker indeed.

I do wonder how large a room would have to be (and ceiling height) to get the very best from what will undoubtedly be superb speakers.

Ps, if I was ever able to afford them, and a house with a room big enough, I’d have to wrap them in a satin black vinyl.

 

[Duke]

What's your take on the imaging of both speakers? We're on a ultimate speaker trip here

Soon as I've set up a pair of each in my mancave, I promise to post my impressions!

Seriously, assuming we're talking about the Dutch & Dutch 15c and the Genelec 8381A, I favor the geometry of the former. I don't like the idea of having the first-arrival sound for the frequency range from maybe 100 Hz to maybe 1 kHz spread out over time, which would be the case unless you are on-axis both horizontally and vertically. Now this bias of mine MAY be mis-placed; maybe IN PRACTICE it doesn't matter within the speaker's normal coverage angles, and I would be much more concerned if the multiple-arrival-times thing was happening north of 1 kHz.

Also playing a role in my bias is this: I prefer to listen from off-axis, perhaps by as much as 15 or 20 degrees, and that might be further off-axis that the 8381A is totally comfortable with.

So actually it is the Genelec 8380A (ideally paired with a distributed multi-sub system) that I would send into the fray against the mighty D&D 15c.

(In fact my idea of an "ultimate speaker" might look a lot like the waveguide + cardioid midwoof of the 15c, but WITHOUT the built-in subs, and then the requisite subwoofage would be supplied by a distributed multi-sub system.)

 

[Satanica]

Also playing a role in my bias is this: I prefer to listen from off-axis, perhaps by as much as 15 or 20 degrees, and that might be further off-axis that the 8381A is totally comfortable with.

So actually it is the Genelec 8380A (ideally paired with a distributed multi-sub system) that I would send into the fray against the mighty D&D 15c.

Interesting, why do you prefer to listen 15-20 degress off axis? Wouldn't this be decided more based on a speaker room combination?
I could be wrong, but I think the Genelec 8380A is narrower than the 8318A in dispersion. The 8318A looks superior to me.

Genelec know what they're doing, I think both of these speakers are deliberately designed to be narrow in dispersion to reduce room interaction in larger studio rooms. I don't think they really give any consideration of using these speakers in a typical domestic environment (not that they can't sound good there too).

 

[Mort]

Interesting, why do you prefer to listen 15-20 degress off axis?

Very common with coaxials.

 

[Satanica]

Very common with coaxials.

Sure, but the D&D 15C ain't.

 

[Pearljam5000]

Is the 15C a 3-way or a 4-way?