This is a review and detailed measurements of the KEF T301C ultra-thin center speaker. It is on kind loan from a member and costs US $450.
As is indicated, this is a very shallow speaker:
Configuration is mid-woofer, tweeter, mid-woofer. There are no ports:
Back panel has a soft-feel ("rubberized") paint. Hopefully it won't get sticky over time.
The kick stand is loose which doesn't give me confidence that it won't fall over although it did not during all of my testing.
Binding posts are screwed in terminals and worked surprisingly well.
Note that the same Speaker is sold as T301 with vertical configuration and mounting hardware. Owner kindly sent that to me as well but given the results below, I don't think we need to measure it.
A compact speaker like this is a dream as far as usability below a TV on the wall which is the type of imagery company uses to promote it. My measurements and listening tests did NOT follow that as I tested it like any stand alone speaker.
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 through the grill). It is getting colder with the measurement room temp at 16 degrees C. Accuracy is better than 1% for most of the range but drops to 2% for part of the spectrum. Grill was left on (not sure if it is removable anyway).
KEF T301C 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:
This is a disappointing response. Yes, without a port and in such a compact enclosure, bass response is sacrificed but what is up with that highly elevated treble response? And much messiness between 900 Hz and 1.5 kHz?
Early window reflections (which do NOT apply fully if you mount it on the wall), doesn't look pretty either:
Predicted in-room response therefore is not what we are looking for:
Near-field response is not very diganostic:
I am measuring one woofer where in reality both are firing and creating interference pattern between them.
I expect the beam width to narrow due to "MTM" configuration and it does, but not nearly as much as we have seen in other speakers:
At first I could not figure out why it is asymmetrical but as I was writing this review, I realized one side has that KEF label so one side will have different response than the other. It also looks like I was off a bit in my centering (hard to see through the grill). Regardless, directivity is quite uneven as we would expect from the design:
And predictably, works better vertically:
There is beaming (narrowing) above 3 to 4 kHz however.
Zooming in the problematic 933 Hz resonance we get this very complex sound field:
I have the video at 45 degrees so that you can see its complexity. There are a lot of components contributing to make it look this odd.
I was impressed with the low distortion of the tweeter:
Impedance dips to the usual 4 ohm region:
For fans of timing graphs, here are the CSD and impulse responses:
KEF T301C Listening Tests and Equalization
Let's get the obvious out of the way: this thing is bright sounding, super bright sounding! Yes, it portrays that impression of "very detailed and high resolution" but come on, this is just too much. The effect is exaggerated here due to lack of bass. So even after I EQed it, it still sounded bright:
That resonance around 1 kHz also contributed to the feeling of brightness so pulling it down helped. I tried to boost the bass response but it just got tubbier sounding. It did not however, fall apart.
There were moments of excellence in high frequency notes. Whether it is helped with frequency response boost there, I am not sure but there was this clarity and niceness that I picked up time and time again.
I checked for listening angle and was surprised that at my listening distance (about 10 feet), it was not an issue moving over one seat. I got close to the speaker and there, it is a problem as you literally hear the speaker center shift from tweeter to the woofer you are closes to. This goes away as you move past 1 meter/3 feet or so. If you are mounting the speaker on the wall next to the speaker and it encourages people to walk up to it, this may be an issue for you.
Wondering about resonances I saw in measurements, I touched the speaker cabinet as it was playing. This thing resonates with *every* note in music! On normal speakers it is the strong bass notes that cause resonances you can easily feel. Here, the cabinet was continuously vibrating no matter how the music changed. Form factor here is really getting in the way of good performance.
Conclusions
When you have a speaker from KEF, yet it is chasing the same marketing message as the rest of the crowd, you want to think that they have somehow bent the laws of physics to do better. While that may be true to a small degree, the T301C (and T301 sister) are just not what I consider hi-fi. It is way too bright. It lacks bass and good luck trying to integrate a sub into it (and two others for left and right in different locations). And has tons of resonances.
Is it better than the sound coming out of a speaker by itself? Sure. but don't put much hope that you can be producing serious fidelity out of this speaker. It just can't do it.
I can't recommend the KEF T301c or T301 for that matter.
----------
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/
As is indicated, this is a very shallow speaker:
Configuration is mid-woofer, tweeter, mid-woofer. There are no ports:
Back panel has a soft-feel ("rubberized") paint. Hopefully it won't get sticky over time.
The kick stand is loose which doesn't give me confidence that it won't fall over although it did not during all of my testing.
Binding posts are screwed in terminals and worked surprisingly well.
Note that the same Speaker is sold as T301 with vertical configuration and mounting hardware. Owner kindly sent that to me as well but given the results below, I don't think we need to measure it.
A compact speaker like this is a dream as far as usability below a TV on the wall which is the type of imagery company uses to promote it. My measurements and listening tests did NOT follow that as I tested it like any stand alone speaker.
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 through the grill). It is getting colder with the measurement room temp at 16 degrees C. Accuracy is better than 1% for most of the range but drops to 2% for part of the spectrum. Grill was left on (not sure if it is removable anyway).
KEF T301C 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:
This is a disappointing response. Yes, without a port and in such a compact enclosure, bass response is sacrificed but what is up with that highly elevated treble response? And much messiness between 900 Hz and 1.5 kHz?
Early window reflections (which do NOT apply fully if you mount it on the wall), doesn't look pretty either:
Predicted in-room response therefore is not what we are looking for:
Near-field response is not very diganostic:
I am measuring one woofer where in reality both are firing and creating interference pattern between them.
I expect the beam width to narrow due to "MTM" configuration and it does, but not nearly as much as we have seen in other speakers:
At first I could not figure out why it is asymmetrical but as I was writing this review, I realized one side has that KEF label so one side will have different response than the other. It also looks like I was off a bit in my centering (hard to see through the grill). Regardless, directivity is quite uneven as we would expect from the design:
And predictably, works better vertically:
There is beaming (narrowing) above 3 to 4 kHz however.
Zooming in the problematic 933 Hz resonance we get this very complex sound field:
I have the video at 45 degrees so that you can see its complexity. There are a lot of components contributing to make it look this odd.
I was impressed with the low distortion of the tweeter:
Impedance dips to the usual 4 ohm region:
For fans of timing graphs, here are the CSD and impulse responses:
KEF T301C Listening Tests and Equalization
Let's get the obvious out of the way: this thing is bright sounding, super bright sounding! Yes, it portrays that impression of "very detailed and high resolution" but come on, this is just too much. The effect is exaggerated here due to lack of bass. So even after I EQed it, it still sounded bright:
That resonance around 1 kHz also contributed to the feeling of brightness so pulling it down helped. I tried to boost the bass response but it just got tubbier sounding. It did not however, fall apart.
There were moments of excellence in high frequency notes. Whether it is helped with frequency response boost there, I am not sure but there was this clarity and niceness that I picked up time and time again.
I checked for listening angle and was surprised that at my listening distance (about 10 feet), it was not an issue moving over one seat. I got close to the speaker and there, it is a problem as you literally hear the speaker center shift from tweeter to the woofer you are closes to. This goes away as you move past 1 meter/3 feet or so. If you are mounting the speaker on the wall next to the speaker and it encourages people to walk up to it, this may be an issue for you.
Wondering about resonances I saw in measurements, I touched the speaker cabinet as it was playing. This thing resonates with *every* note in music! On normal speakers it is the strong bass notes that cause resonances you can easily feel. Here, the cabinet was continuously vibrating no matter how the music changed. Form factor here is really getting in the way of good performance.
Conclusions
When you have a speaker from KEF, yet it is chasing the same marketing message as the rest of the crowd, you want to think that they have somehow bent the laws of physics to do better. While that may be true to a small degree, the T301C (and T301 sister) are just not what I consider hi-fi. It is way too bright. It lacks bass and good luck trying to integrate a sub into it (and two others for left and right in different locations). And has tons of resonances.
Is it better than the sound coming out of a speaker by itself? Sure. but don't put much hope that you can be producing serious fidelity out of this speaker. It just can't do it.
I can't recommend the KEF T301c or T301 for that matter.
----------
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/
