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Definitive Demand D11 Speaker Review

amirm

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This is a review and detailed measurements of the Definitive Technology Demand D11 bookshelf/stand-mount speaker. It is on kind loan from a member who I think bought it used. The normal cost on Amazon is US $1,000 including Prime shipping.

I must stay, the enclosure is very attractive and well built. But I don't care for the look of the drivers:

Definitive Technology Demand D11 Bookshelf Speaker Review.jpg


The offset tweeter is supposed to reduce effect of diffraction but it bugs me and I don't even have ADD! There is a passive radiator on top which you can't see but is covered in nice fabric.

Back panel terminals are too close as usual but otherwise feel fine:

Definitive Technology Demand D11 Bookshelf Speaker Back Binding Posts Bi-wire Bi-amp Review.jpg


Speaker is built in China.

Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to subtract room reflections (so where I measure it doesn't matter). It also measures the speaker at close distance ("near-field") which sharply reduces the impact of room noise. Both of these factors enable testing in ordinary rooms yet results that can be more accurate than an anechoic chamber. In a nutshell, the measurements show the actual sound coming out of the speaker independent of the room.

I used over 800 measurement point which was enough to compute the sound field of the speaker within 1% error.

Temperature was 78 degrees. Measurement location is at sea level so you compute the pressure.

Measurements are compliant with latest speaker research into what can predict the speaker preference and is standardized in CEA/CTA-2034 ANSI specifications. Likewise listening tests are performed per research that shows mono listening is much more revealing of differences between speakers than stereo or multichannel.

Was not sure what to use for measurement axis given the offset tweeter. I decided to place it slightly to the left of the tweeter center.

Spinorama Audio Measurements
Acoustic measurements can be grouped in a way that can be perceptually analyzed to determine how good a speaker is and how it can be used in a room. This so called spinorama shows us just about everything we need to know about the speaker with respect to tonality and some flaws:

Definitive Technology Demand D11 Bookshelf Speaker Spinorama Audio Measurements.png


Gosh, this is close to being good had we not had the sharp jaggies around 600 Hz. The disturbance is narrow in nature so maybe not too audible.

Early window reflections show the same indicating it is not simple diffraction:

Definitive Technology Demand D11 Bookshelf Speaker Spinorama Early Reflections Audio Measureme...png


Predicted in-room response shows what we already know:

Definitive Technology Demand D11 Bookshelf Speaker Spinorama Predicted In-room Audio Measureme...png


There is a slight rise in energy in lower treble region that would lead to a bit of brightness. And whatever that peak does around 600 Hz.

The peak appears in the woofer response but could be due to the passive radiator which I did not measure due to its location:

Definitive Technology Demand D11 Bookshelf Speaker Woofer Tweeter Audio Measurements.png


Impedance dips to 4 ohm which is typical of these small speakers:

Definitive Technology Demand D11 Bookshelf Speaker Impedance and Phase Audio Measurements.png


Radiation in horizontal axis is not flat which is a bit of concern:

Definitive Technology Demand D11 Bookshelf Speaker Beamwidth Audio Measurements.png


Here is the same in the form of a heatmap:

Definitive Technology Demand D11 Bookshelf Speaker Horizontal Directivity Audio Measurements.png


Notice how we have more energy on the right than on the left due to tweeter being offset. If we made that the upper range of woofer would be out of alignment.

Here it is vertically:

Definitive Technology Demand D11 Bookshelf Speaker Vertical Directivity Audio Measurements.png



Speaker Distortion Measurements
Playing a sweep at both 86 and 96 dB SPL @ 1 meter shows that the woofer is not happy at either level:

Definitive Technology Demand D11 Bookshelf Speaker Distortion Relative THD Audio Measurements.png


There was a horrendous rattle/noise at very low frequencies as you see below:

Definitive Technology Demand D11 Bookshelf Speaker Distortion THD Audio Measurements.png


So best not feed it ultra low bass.

Finally CSD/waterfall:

Definitive Technology Demand D11 Bookshelf Speaker CSD Waterfall Audio Measurements.png


Speaker Subjective Listening Test
I listened to the D11 without seeing the measurements. First impression was positive. My reference tracks translated well and provided good "audiophile" enjoyment as they should. After a few minutes, I noticed a bit of brightness in female "s" sounds. And a bit of unhappiness in upper bass region in my brain.

I then looked at the measurements and attempted to fix these. Putting a notch at 618 Hz even with "high q" (narrow) filter caused bass to be lost which subjective is not a good trade off. I think the problem is that we have a dip right before this region with poor directivity to boot so EQ is not as simple as it seems.

I added very low Q (1) dip centered around 6 kHz and I thought that made a positive change in shaving the highs some. But it turned out to be more of a taste thing so I am not showing it.

At this point, I turned off the EQ and played music for a while and sound was enjoyable. With exception of tracks with deep bass which caused static in the woofer, the D11 could play quite loud without bottoming out. Its deep cabinet is helping in this regard.

Conclusions
The cabinet construction and finish is definitely a step above budget speakers. The look of the drivers is gimmicky but maybe you can put the grill on to hide it which may also lower the highs and make them acceptable. Subjectively the D11 sound was almost right.

So while not a perfect speaker, I generally liked the Definitive Demand D11 and am putting it on my recommended list. Note that I am not paying attention to price with this.

-----------
As always, questions, comments, recommendations, etc. are welcome.

Miracles happen: the panthers have volunteered to help pick our incredible garden harvest. Alas, there is a whole set of regulations for panthers doing such field work requiring major investment in protective gear. They need googles to protect their eyes, speaker shoes to keep the dirt from getting stuck to their paws, etc. That is where you come in with donating money for this equipment using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

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KaiserSoze

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This speaker is ridiculously overpriced. At Crutchfield and elsewhere the price per pair is over $1100. There are lots and lots of better speakers for a whole lot less money. This newer Definitive Technology line looks nice, but the measurements just do not support the price. Not even close.
 

MZKM

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The offset tweeter is supposed to reduce effect of diffraction but it bugs me and I don't even have ADD!
Is it at least mirrored on each side, or are they identical? I hate non-symmetrical designs which aren't mirrored, totally looks off.

It does looks to do the job though, the rise in the horizontal off-axis around 5kHz is lower than other speakers also using flat edge cabinets. But who know how it would compare to a centered tweeter and rounded/chamfered edges.
 
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cistercian

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Thanks Amir! Far too tiny for my taste...but a good review!
 

milosz

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The speaker tests show that many problems can not be solved by EQ. EQ is good for "ordinary" response peaks or valleys, or for overall tilt; and one can use EQ to shore up the inevitable low end rolloff a little as long as the woofer can handle the extra work without distorting too much.

But directivity errors and time-domain problems like ringing or other artifacts of stored energy can't be fixed by EQ. A little EQ at a point where the speaker rings can help keep the ringing from being excited, but this only helps a little.

Other techniques available in DSP such as frequency-selective delay and so on can help with some flaws not fixed by EQ. In my experience, DEQX's correction algorithm offers some interesting and useful correction in these regimes, and Dirac talks about time-domain corrections but I have no experience with Dirac. The other automated correction schemes appear to be limited to EQ.
 

Kachda

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@amirm liking this speaker subjectively throws the hypothesis of him liking wide directivity speakers, out of the window
 
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sweetchaos

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KaiserSoze

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@amirm liking this speaker subjectively throws the hypothesis of him looking wide directivity speakers out of the window

Ha. At first I thought you meant "looking out the window at wide directivity speakers."
 

Tom C

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This speaker is ridiculously overpriced. At Crutchfield and elsewhere the price per pair is over $1100. There are lots and lots of better speakers for a whole lot less money. This newer Definitive Technology line looks nice, but the measurements just do not support the price. Not even close.
It seems Amir was trying not to overstate it, but I fear your comment is spot on.
 

KaiserSoze

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It was on sale for $530usd between Dec 17, 2019 - Jan 5, 2020 on amazon. :eek:

I'd have difficulty saying that they are a fair value at $500/pair. Distortion throughout the woofer's range is much higher than it is for other speakers of similar size and design, and the frequency response is mediocre at best. I think Amir liked them mainly because they match the color of his hat.
 

aarons915

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When I heard this new series at best buy I was a bit disappointed myself, they aren't bad but the previous Studio monitor series sounded and looked better in my opinion, I brought the SM45 home for an audition and they sounded great although I didn't end up keeping them.
 

matthewgp

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I would be curious if either Klippel had a recommendation on how to measure a speaker with an offset tweeter or if Definitive Technology had a response to how they think it should be measured.

There also was no mention of trying a 25 hz low pass filter or not. I assume it was tried and didn't help. Surprised to hear about the bass rattle though. Will be curious if the member hears the rattle in the other speaker.
 

wwenze

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The speaker tests show that many problems can not be solved by EQ. EQ is good for "ordinary" response peaks or valleys, or for overall tilt; and one can use EQ to shore up the inevitable low end rolloff a little as long as the woofer can handle the extra work without distorting too much.

But directivity errors and time-domain problems like ringing or other artifacts of stored energy can't be fixed by EQ. A little EQ at a point where the speaker rings can help keep the ringing from being excited, but this only helps a little.

Other techniques available in DSP such as frequency-selective delay and so on can help with some flaws not fixed by EQ. In my experience, DEQX's correction algorithm offers some interesting and useful correction in these regimes, and Dirac talks about time-domain corrections but I have no experience with Dirac. The other automated correction schemes appear to be limited to EQ.

Even without the consumer knowing the science behind, good manufacturers have already moved from "just good on-axis FR only" to waveguides. Of course I'm talking about those using waveguides to tackle this particular problem i.e. not Klipsch.

As the complexity of design increases, the complexity of reviewers also need to increase so that readers can understand those horns are not just for show to make the speaker look like it has a $3000 price tag slapped on.

The next stage would be manufacturers also considering actual implementation e.g. having a monitor screen acting like a baffle.
 

wwenze

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The strong dip/peak ~600Hz is quite similar to what we saw with the Buchardt S400.

So some kind of port (or radiator) cancellation, right?

And I see the website:
- Integrated passive bass radiator in each speaker produces superior low-end extension

I look at the photos, and "where is the radiator?" It looks like a sealed design at first glance.

EDIT: Oh, hidden in the top, wow.
 
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