Erin's Audio Corner gets a Klippel NFS!

[q3cpma]

IMD could be interesting, especially comparing with a "true" 3-way speaker (the 8c is more of a 2-way with integrated subwoofer).

 

[Spocko]

Today was an eventful day. The weather was finally nice enough for me to measure subwoofers outdoors so I measured both the SVS SB2000 Pro and the SVS SB3000 subwoofers.

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I also finished testing of the Dutch & Dutch 8c. As some of you already know, the Dutch & Dutch 8c is a speaker that breaks the norm. It is designed to be placed near a back wall in order to provide boundary gain. In order to achieve boundary gain, however, a typical speaker also loses timbre due to the rear wall reflections. With a cardioid speaker (such as the D&D 8c), the rear wall reflections are effectively "muted" and you are left with a forward-firing only speaker above 100Hz (below which, the subs are omnidirectional but cut off sharply).

This presents a bit of a challenge when analyzing performance. Ideally you measure a speaker anechoically to see what happens when the room is not a factor in the performance. So, I did that using Klippel's NFS. This gives us all a baseline understanding of the speaker's performance. However, I also needed a way to characterize performance in the situation it is designed for: near a boundary for <100Hz reinforcement.

Therefore, I used high engineering (see: scrap wood) to build a platform for the speaker so the subwoofers could load off the ground - effectively becoming the "rear wall", if you will. And then I measured the performance in this manner.

Now I have a full SPIN set of data for anechoic measurements but we also have a quasi-anechoic measurement via the ground plane method to see how the boundary loading improves performance.

To be honest, there were a couple times today where I thought "I'm not getting paid enough to do this for free".



Anyway... stay tuned for results.

Wait, you're doing this for free?? Clearly, your wife loves you for your selfless endeavors!

 

[pierre]

Or just use SVG, no need for another retarded "website that flat-out doesn't work without Jabbascript".

If your browser in smart enough to render SVG I guess it can do JavaScript. There are only good browsers now. If you are using lynx or w3m then ... sure.

 

[617]

Indeed, and the sneak preview looked fantastic.

Oh damn I didn't even notice. That thing is perfect CD down to 200hz. That's far lower than the genelecs. Absolutely amazing performance. Tight uniform directivity.

Truly next gen audio.

 

[q3cpma]

If your browser in smart enough to render SVG I guess it can do JavaScript.

Netsurf and Links2 can do SVG. You can also disable javascript for sanity reasons, while SVG usually isnt too insane if you ignore the embedded JS and animation part of the spec.

There are only good browsers now. If you are using lynx or w3m then ... sure.

"Good browser" is basically an oxymoron, as long as you consider the latest HTML + CSS + ECMAScript (and the "mandatory" sandbox/JIT to avoid being a security/performance hog; hardware based vulns like rowhammer or Spectre are still there, as JS is basically a RCE passing as a "feature") to be the bare minimum for a browser. And all of this just for shiny that sells.

Some opinionated or factual blog posts describing the obvious madness that most don't want to see:
https://drewdevault.com/2020/03/18/Reckless-limitless-scope.html
https://flak.tedunangst.com/post/browser-ktrace-browsing
https://flak.tedunangst.com/post/firefox-vs-rthreads
https://flak.tedunangst.com/post/rough-idling
https://flak.tedunangst.com/post/accidentally-nonblocking
https://beauty-of-imagination.blogspot.com/2016/01/tcltk-vs-web-we-should-abandon-web.html
https://dev.to/mkrl/javascript-quirks-in-one-image-from-the-internet-52m7


By the way, thanks to ASR for working perfectly without JS. The great protection racket/Tor firewall known as Cloudflare is less nice, but that's how it is.

 

[hardisj]

Wait, you're doing this for free?? Clearly, your wife loves you for your selfless endeavors!

Haha. Yep. This is my hobby. Done in my spare time. I’ve been testing transducers and speakers (mostly transducers) with Klippel equipment and and on for about 10 years now.

My wife is very supportive of what I do. Surprisingly so, to be honest.

 

[hardisj]

Guys, please take the JavaScript OT discussion to another thread. I don’t want a 5 page argument on this thread about it.

 

[q3cpma]

Oh damn I didn't even notice. That thing is perfect CD down to 200hz. That's far lower than the genelecs.

The 8361A is CD down to 180~200 Hz too, on its side (a bit less clean around 500 Hz, though). We need the 8c's vertical dispersion to really compare both.

 

[q3cpma]

Guys, please take the JavaScript OT discussion to another thread. I don’t want a 5 page argument on this thread about it.

Don't worry, my crusade won't go further.

 

[richard12511]

Oh damn I didn't even notice. That thing is perfect CD down to 200hz. That's far lower than the genelecs. Absolutely amazing performance. Tight uniform directivity.

Truly next gen audio.

It actually looks like it goes down to almost 100Hz, which is close to what they claim. Definitely much lower than the Genelecs, and it honestly looks a little more consistent than the Genelec.

 

[Muelli]

IMO the best-looking and most information-rich polar maps currently published are Sound und Recording's. Their steps do obscure some fine detail (1/3 octave smoothing, colorization more like a beamwidth graph than most polar maps) but they manage to convey both FR uniformity and directivity trends in a clean graph. For this speaker (JBL 705P) it doesn't especially matter, but their polar maps are not normalized.

Please have a look at the text below the graph, it says "Norm. to 0°".

I believe it means normalized to 0°.

 

[Hephaestus]

No surprise what comes to 8c directivity - they are stellar speakers.

 

[Spocko]

No surprise what comes to 8c directivity - they are stellar speakers.

So how much of this well controlled directivity is as a result of the physical design and how much from the DSP? If DSP, then we can expect to see this level of performance coming down to consumer friendly levels in the near future (like the Buchardt A500).

 

[q3cpma]

So how much of this well controlled directivity is as a result of the physical design and how much from the DSP? If DSP, then we can expect to see this level of performance coming down to consumer friendly levels in the near future (like the Buchardt A500).

DSP can't really control directivity, unless you include what's done in the crossover (impacting only the crossover point and around, then) and the delay used in solutions like the Kii three or PA stuff. In the 8c's case, the mechanism is purely passive, mimicked on ME Geithain's.

 

[Spocko]

Haha. Yep. This is my hobby. Done in my spare time. I’ve been testing transducers and speakers (mostly transducers) with Klippel equipment and and on for about 10 years now.
My wife is very supportive of what I do. Surprisingly so, to be honest.

HEY, just caught your excellent YT interview with Gene of Audioholics, quick subwoofer question for you: what do you recommend if I needed a solid LFE home theater sub connected to a pre/pro that has its own bass management (don't need the sub to have sophisticated settings/DSP/app)? Would it be the $800 Monoprice THX 12-inch sub?

 

[TimVG]

So how much of this well controlled directivity is as a result of the physical design and how much from the DSP? If DSP, then we can expect to see this level of performance coming down to consumer friendly levels in the near future (like the Buchardt A500).

They started out by optimizing as much as possible on an acoustical and structural level, and then used DSP as icing on the cake. As you'll probably see soon in the measurements, it's an extremely well thought out design.

 

[Spocko]

DSP can't really control directivity, unless you include what's done in the crossover (impacting only the crossover point and around, then) and the delay used in solutions like the Kii three or PA stuff. In the 8c's case, the mechanism is purely passive, mimicked on ME Geithain's.

They started out by optimizing as much as possible on an acoustical and structural level, and then used DSP as icing on the cake. As you'll probably see soon in the measurements, it's an extremely well thought out design.

Aaaah, so even software can only do so much! but this begs the question: since it's easy enough to pull these speakers apart to duplicate their key design principles, I'm wondering why more companies are not copying these designs? I guess it could be argued that the JBL 306P is one such fine example, but I'm surprised there aren't more out there. We've seen Topping and SMSL do this with DACs - maybe they should start selling speakers too.

 

[MZKM]

Aaaah, so even software can only do so much! but this begs the question: since it's easy enough to pull these speakers apart to duplicate their key design principles, I'm wondering why more companies are not copying these designs? I guess it could be argued that the JBL 306P is one such fine example, but I'm surprised there aren't more out there. We've seen Topping and SMSL do this with DACs - maybe they should start selling speakers too.

Well, the front half of the speaker wouldn’t be terribly hard to replicate. The difficult part is the cardiod and rear drivers, where in the software you tell it the distance from the front wall and it then adjusts roll-off, as well as even timing I believe in order to have optimal bass.

As for Buchardt, their new speakers have awesome tech. However, they still use a 0.75” tweeter to my knowledge, which (to my knowledge) hinders their crossover region even with their large waveguide and the thus have a dip in the sound power, crossing over a 6“ driver at 2800Hz will do that. Here is the A700 measurements from their site:

The owner has stated this was chosen I order to have a wider soundstage in the upper treble. That is a valid reason to do this, but I wonder which would sound better.

 

[TimVG]

Aaaah, so even software can only do so much! but this begs the question: since it's easy enough to pull these speakers apart to duplicate their key design principles, I'm wondering why more companies are not copying these designs? I guess it could be argued that the JBL 306P is one such fine example, but I'm surprised there aren't more out there. We've seen Topping and SMSL do this with DACs - maybe they should start selling speakers too.

First of all I believe these companies (D&D, Kii, ..) hold several patents. Second, cost & complexity. Doing a 2-way cardioid needs a lot of displacement and power behind it for it to be feasable, the cabinet is also more time consuming to produce, and these factors drive up cost. Third, not every company takes measurements as serious as the aformentioned. Amphion has a passive 3-way deploying some sort of cardioid midrange, there's also Gradient, Geithain has a line of cardioid models, D&D, Kii, more recently GGNTKT, in pro audio there's Fulcrum acoustics.. And cardioid bass arrays have been used for many years now for PA purposes. It's not new tech, but it's been only since recently that the concept has really taken off in home/studio audio.

 

[ctrl]

As for Buchardt, their new speakers have awesome tech. However, they still use a 0.75” tweeter to my knowledge, which (to my knowledge) hinders their crossover region even with their large waveguide and the thus have a dip in the sound power, crossing over a 6“ driver at 2800Hz will do that. Here is the A700 measurements from their site:

In most cases, it is probably a deliberate design decision to reduce the sound power in the 2-4kHz range, often with the goal that the lateral reflections in this range do not indicate an exaggeration.
Whereby it is almost a bit excessive with the A700 - but if it has a positive effect on the sound, why not?

The measurements from @napilopez show that something comparable was also the development goal for the 8C. In the range 2-4kHz the axis frequency response was only slightly reduced, since there is probably no widening in the sound radiation in this range.