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KEF T101 Review (Thin Speaker)

Rate this speaker:

  • 1. Poor (headless panther)

    Votes: 157 91.3%
  • 2. Not terrible (postman panther)

    Votes: 11 6.4%
  • 3. Fine (happy panther)

    Votes: 0 0.0%
  • 4. Great (golfing panther)

    Votes: 4 2.3%

  • Total voters
    172

amirm

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This is a review and detailed measurements of the KEF T101 slim/wall mountable home theater speaker. It is on kind loan from a member and costs US $650 for a pair.
KEF T101 Review Flat Home Theater Speaker Wall Mount.jpg

This is a very solidly built thin speaker:
KEF T101 Review Wall Mount Flat Home Theater Speaker Wall Mount.jpg


It is clear a lot of engineering has gone into it. KEF developed a very shallow conventional midrange for this 2-way speaker in order to get the case so thin. The series was introduced back in 2011.

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.

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.

Reference axis was the center of the tweeter (aligned by eye). The grill was left in place (not sure it is removable anyway). Measurement room was at 10 degrees C which may lower bass output a bit. Accuracy is better than 1% for most of the audio spectrum degrading to 2% above 4 kHz.

Note: KEF makes a special stand for this speaker that modifies its frequency response somehow. I did not have that and tested the unit as is.

KEF T101 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:

KEF T101 Measurement Frequency Response Flat Home Theater Speaker Wall Mount.png


Wow, I don't remember seeing such an uneven frequency response in all the testing I have done. We have three broad areas of error, two of which are boost and one is a dip. Directivity is good for some of this range but gets messed up during the crossover frequency. Speaking of which, here is the near-field response of each driver:

KEF T101 Measurement Near field Frequency Response Flat Home Theater Speaker Wall Mount.png


Unless I am aligning the two curves wrong, it seems that the tweeter is crossed at too high a frequency (or vice versa) causing a droop in the intersection which is what we saw in the spin graph (between 1 and 2 kHz). There is also resonance or lack of baffle compensation for the midrange driver which could be responsible for peaking we saw centered around 880 Hz.

Early reflections are a mess as well as one would predict:

KEF T101 Measurement early window Frequency Response Flat Home Theater Speaker Wall Mount.png


And as a result, the predicted in-room response:

KEF T101 Measurement Predicted In-room Frequency Response Flat Home Theater Speaker Wall Mount.png


We can see the crossover directivity error clearly in our horizontal beamwidth and directivity measurements:

KEF T101 Measurement Horizontal Beam width Flat Home Theater Speaker Wall Mount.png


KEF T101 Measurement Horizontal Directivity Flat Home Theater Speaker Wall Mount.png


Vertical response gets much worse if you go below the tweeter axis so try to point it toward your ear:
KEF T101 Measurement Vertical Directivity Flat Home Theater Speaker Wall Mount.png


Power handling is quite good for such a shallow and small speaker, albeit aided by lack of bass:


KEF T101 Measurement THD Distortion Response Flat Home Theater Speaker Wall Mount.png


KEF T101 Measurement Distortion Response Flat Home Theater Speaker Wall Mount.png


As usual, our impedance and phase measurement shows low frequency resonances:

KEF T101 Measurement Impedance and phase Response Flat Home Theater Speaker Wall Mount.png


Impedance of 3.2 ohm is quite low but you probably won't be pushing this speaker too loud so may be OK.

And for fans of timing analysis, here are the three of them:

KEF T101 Measurement CSD Waterfall Response Flat Home Theater Speaker Wall Mount.png



KEF T101 Measurement Impulse Response Flat Home Theater Speaker Wall Mount.png


KEF T101 Measurement Step Response Flat Home Theater Speaker Wall Mount.png


KEF T101 Listening Tests and Equalization
Seeing how one of the main applications are wall mounting I put the T101 in front of my flat screen TV to simulate a back wall. What I heard was the least hi-fi sound I could describe! I had to immediately shut the system down and move it to the stand away from walls which provided some relief. Still, overall signature was still wrong and very bright. Some of this is due to lack of bass but still, I could not tolerate it for much before applying EQ:


KEF T101 Equalization EQ Wall Mount Flat Home Theater Speaker Wall Mount.png


The first two filters are self explanatory. I put in the shelf quickly to get rid of the brightness. A more precise filter may have done better as the sound was still on the bright side. But compared to before, at least it was not flat broken sounding.

I was impressed with the ability of the T101 to play loud. Yes, there is zero deep bass but still, this is a little flat panel speaker so this much power handling was impressive.

I tried to add some bass to it with a filter at 100 and then 150 Hz but it just got tubby and poor sounding so I abandoned that.

Conclusions
I admire the three years of engineering KEF says they put in this product. I am amazed though at the end they decided to create such an objectively flawed response for a company with their skills and tools. What were they thinking? Crossover with a hole in it? Terrible boosted lower terrible? To what end? Yes, there is a bit of "showroom sound" effect there but come on, let's follow good practices in speaker design. Given the very positive effects of EQ, I can see that the components are wasted away in this implementation.

Needless to say, I can't recommend KEF T101, period. It is one, if not the worse sounding speaker I have tested. Yes, I appreciate the size constraints but per above, I think they could have done much better. EQ solves major ills with the unit but not to the level that makes it OK to my ears.

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

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

Attachments

  • KEF T101 Vertical ASR Frequency Response.zip
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Blumlein 88

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typo where you say Crossover hold in summary. Maybe you meant hole.

Yeah, pretty awful result. I used to have nightmares of being an engineer having to work on something I knew as terrible. I'd think the engineers on this felt that way.
 

respice finem

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So, somehow, did KEF lose against... IKEA? ;) (or Sonos)
 

thewas

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Here are the engineers in this brief marketing video:

What a shame that they put so much effort in the drivers and seem to strongly neglected the tuning. Would be interesting though to measure (or at least look inside the circuit of "smart x-over adjustment" when mounted to the stands they provided as shown at 3:30.
 

GWolfman

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Some of their other products have high marks. I wonder if someone was forced to make this (i.e., no heart) or they were nearing a deadline (i.e., rushed).
 

HammerSandwich

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Note: KEF makes a special stand for this speaker that modifies its frequency response somehow. I did not have that and tested the unit as is.
I have no idea about KEF's EQ curves, but your results look like tuning for wall mounting to me.

If bracket + speaker placed the baffle ~90mm from the front wall, SBIR would create dips at 900Hz & 4.5kHz and peaks at ~2.7 & 6.3kHz. You still have a hole at 1.5kHz, but the nulls complement Klippel's PIR nicely enough. The tweeter-range SBIR effects could be easily reduced with an absorber, assuming you really wanted to tweak your "lifestyle" speakers so seriously.

That said, I'd jump on Q150s for less money.
 

McFly

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Like to see anyone else do a product with similar dimensions do any better. I mean, it is poor, but the design constraints are very high. I have some of those here - perhaps I should crack one open and have a go at the crossover?
 

H-713

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I have no idea about KEF's EQ curves, but your results look like tuning for wall mounting to me.

If bracket + speaker placed the baffle ~90mm from the front wall, SBIR would create dips at 900Hz & 4.5kHz and peaks at ~2.7 & 6.3kHz. You still have a hole at 1.5kHz, but the nulls complement Klippel's PIR nicely enough. The tweeter-range SBIR effects could be easily reduced with an absorber, assuming you really wanted to tweak your "lifestyle" speakers so seriously.

That said, I'd jump on Q150s for less money.
I sure hope that's what it is. I can't imagine that someone at KEF would pass this off as "good". They're smart engineers, they know (or should know) better.
 

Χ Ξ Σ

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This is probably one of those cases where adding a subwoofer would triple the preference rating.

Unless of course the rating goes negative again, which is very likely as well.
 

Tangband

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This is a review and detailed measurements of the KEF T101 slim/wall mountable home theater speaker. It is on kind loan from a member and costs US $650 for a pair.
View attachment 176322
This is a very solidly built thin speaker:
View attachment 176323

It is clear a lot of engineering has gone into it. KEF developed a very shallow conventional midrange for this 2-way speaker in order to get the case so thin. The series was introduced back in 2011.

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.

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.

Reference axis was the center of the tweeter (aligned by eye). The grill was left in place (not sure it is removable anyway). Measurement room was at 10 degrees C which may lower bass output a bit. Accuracy is better than 1% for most of the audio spectrum degrading to 2% above 4 kHz.

Note: KEF makes a special stand for this speaker that modifies its frequency response somehow. I did not have that and tested the unit as is.

KEF T101 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:

View attachment 176324

Wow, I don't remember seeing such an uneven frequency response in all the testing I have done. We have three broad areas of error, two of which are boost and one is a dip. Directivity is good for some of this range but gets messed up during the crossover frequency. Speaking of which, here is the near-field response of each driver:

View attachment 176326

Unless I am aligning the two curves wrong, it seems that the tweeter is crossed at too high a frequency (or vice versa) causing a droop in the intersection which is what we saw in the spin graph (between 1 and 2 kHz). There is also resonance or lack of baffle compensation for the midrange driver which could be responsible for peaking we saw centered around 880 Hz.

Early reflections are a mess as well as one would predict:

View attachment 176327

And as a result, the predicted in-room response:

View attachment 176328

We can see the crossover directivity error clearly in our horizontal beamwidth and directivity measurements:

View attachment 176329

View attachment 176330

Vertical response gets much worse if you go below the tweeter axis so try to point it toward your ear:
View attachment 176331

Power handling is quite good for such a shallow and small speaker, albeit aided by lack of bass:


View attachment 176332

View attachment 176333

As usual, our impedance and phase measurement shows low frequency resonances:

View attachment 176334

Impedance of 3.2 ohm is quite low but you probably won't be pushing this speaker too loud so may be OK.

And for fans of timing analysis, here are the three of them:

View attachment 176335


View attachment 176336

View attachment 176337

KEF T101 Listening Tests and Equalization
Seeing how one of the main applications are wall mounting I put the T101 in front of my flat screen TV to simulate a back wall. What I heard was the least hi-fi sound I could describe! I had to immediately shut the system down and move it to the stand away from walls which provided some relief. Still, overall signature was still wrong and very bright. Some of this is due to lack of bass but still, I could not tolerate it for much before applying EQ:


View attachment 176338

The first two filters are self explanatory. I put in the shelf quickly to get rid of the brightness. A more precise filter may have done better as the sound was still on the bright side. But compared to before, at least it was not flat broken sounding.

I was impressed with the ability of the T101 to play loud. Yes, there is zero deep bass but still, this is a little flat panel speaker so this much power handling was impressive.

I tried to add some bass to it with a filter at 100 and then 150 Hz but it just got tubby and poor sounding so I abandoned that.

Conclusions
I admire the three years of engineering KEF says they put in this product. I am amazed though at the end they decided to create such an objectively flawed response for a company with their skills and tools. What were they thinking? Crossover with a hole in it? Terrible boosted lower terrible? To what end? Yes, there is a bit of "showroom sound" effect there but come on, let's follow good practices in speaker design. Given the very positive effects of EQ, I can see that the components are wasted away in this implementation.

Needless to say, I can't recommend KEF T101, period. It is one, if not the worse sounding speaker I have tested. Yes, I appreciate the size constraints but per above, I think they could have done much better. EQ solves major ills with the unit but not to the level that makes it OK to my ears.

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

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
Interesting review.:)

You wrote:

”Seeing how one of the main applications are wall mounting I put the T101 in front of my flat screen TV to simulate a back wall. What I heard was the least hi-fi sound I could describe! I had to immediately shut the system down and move it to the stand away from walls which provided some relief.”

Clearly this is my own experience with all inwall loudspeaker I have heard, including my own I had in my house a couple a years ago. Putting a loudspeaker more than 2 ms ( 70 cm ) away from the wall create SBIR but the sound gets much clearer anyway because of less interference in the treble area within this 2 ms. Early reflections within 2 ms clearly sounds bad in my experience.

What is your experience about this ?
 

KMO

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As discussed in the T301 review thread, this is specifically tuned for wall placement, and the floor stand they provide has a signal path with a passive filter in it to correct the response for free-standing.

Using it as free-standing without that filter is not the design intent.

Although my educated guess is that filter is probably only a shelf filter lowering stuff above the midrange by 3-6dB, similar to the "band 3" Amir applied.

The other spikes (which may be intentional anti-SBIR for wall mounting) would probably remain.
 
OP
amirm

amirm

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Using it as free-standing without that filter is not the design intent.
As you see in the review picture, it comes with a fixture to use it free-standing without the fancy stand. So it is definitely part of the design to use it this way. As to the fancy stand, they need to document what it does. Without it, we don't know what it does.
 

bigjacko

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31 votes and 100% headless panther???? That is quite cool, I never see that before.

The driver itself performed pretty good, considering the mid range is only 27mm tall. The distortion is excellent in mid range duty, but falls off at low bass as expected. They mentioned they have waveguide on the tweeter, but sadly did not address the directivity mismatch. I think the crossover is clearly flawed or maybe damaged, I guess anyone taking half an hour can do even better than this. If someone can ask KEF about this review that might solve some mistery in crossover.
 

KMO

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So, somehow, did KEF lose against... IKEA? ;) (or Sonos)
Certainly seems so, but the "somehow" includes 10 years of technology advance. Plus aiming at a different market.

KEF's version is entirely passive, aimed at home theatre integration, while Sonos can take advantage of now-cheaper DSP and amplification, but is a standalone beast (although maybe integrates with other Sonos bits?).

I don't think there are many directly equivalent passive competitors, actually. The T series keeps coming up in discussions for easy Atmos fittings, despite its age, basically by default.
 

Xmech team

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Most of these in-wall speakers exist to please installers and "clutter-free" HT enthusiasts. While Kef has great engineers, the company as whole needs to cater to different clients' demands. Compromises have to be made. That being said, I would like to see an in-ceiling speaker on Klippel :)... Especially the GoldenEar Invisa HTR 7000. Maybe the reason people are always complaining about poor Atmos is not the mix but the speakers
 
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