This is a review and detailed measurements of the Tannoy Revolution XT 6 stand-mount/bookshelf speaker. It is on kind loan from a local member. They cost US $1,200 but I see them discounted to $1,050.
The industrial design of the XT6 is unique with downfiring port that is integrated into the base:
I like it!
While I did not mess with it, I think the angle is adjustable.
This is of course a coaxial design with the tweeter integrated into the center of the "woofer."
Terminals were high quality and easy to turn.
Speaker is designed in UK but manufactured in China. So yes, our scrutiny of UK designed speakers continues.
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 sufficient to compute the sound field of the speaker.
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:
Focusing on the all important on-axis (direct path from tweeter to your ear) we see a couple of significant dips and rising amplitude above 3 kHz neither one of which is good.
On the positive front, directivity -- how close on-axis sound matches what reflects from other surfaces -- is very good with exception of one glitch around 2.5 kHz.
Because of the above, our important early reflections pretty much mirror the on-axis response:
Putting the two together we get our predicted in-room response:
This says you are going to have a somewhat bright sound and with some parts of your music permanently EQed down. The dip in upper bass is most problematic as it is going to take away some "warmth" and detail in bass frequencies. The exaggeration in upper registers may tend to be good in the short term but not so good in longer term.
The jaggies at the end visually are bad but I suspect they are two narrow relative to our auditory bandwidth to be audible as such.
Beam width horizontally is not that wide so suggest toeing in the speaker toward your ear more or less:
Within that +-50 degree window you will have even response though which is good.
Here is the same view in our 3-D map:
We see a nice beam in red but also sections taken out. Former is good, latter not so much.
Vertically the coaxial design comes through showing much better response than typical 2-way speaker:
So maybe if you have bare floors and ceiling that is close, this works better than non-coaxial design, all else being equal (which they definitely are not).
Impedance and waterfall show some resonances that should not be there:
Speaker Distortion Deep-dive:
Avid readers of my speaker reviews know that I am increasingly suspecting distortion plays a role at least in my listening impressions. Research says they play a distant role to tonality which I agree with. But once you have tonality, then I think distortion matters. That is the theory anyway.
To that end, I thought I significantly ratchet up our distortion measurements. Alas, doing so with Klippel NFS is hard. Most distortion measurement features in that system are optional and cost significant money. In addition, they seem to be tailored toward driver measurements than speaker (e.g. wanting me to monitor voice coil temps and such which is not practical in a speaker). Finally, usability is not great because all measurements are optimized for frequency response with asynchronous system (play a full sweep and then analyze).
I am spoiled with my Audio Precision APx555 analyzer which makes such analysis trivial. So I finally broke down and started to use the AP analyzer for speaker testing. But we are getting ahead of ourselves. Let's review our still useful Klippel distortion measurements:
Wow, this speaker wants to produce distortion! Even at 86 dBSPL at 1 meter, it has that peak around 550 Hz and too high of distortion for the rest of the spectrum.
Once we go up to 96 dB, hell breaks loose and we have massive peaks now (right). We are talking 4 to 5% distortion where our hearing is sensitive.
No wonder then that the XT 6 easily exceeds my criteria of 50 dB while playing at 96 dB SPL:
I spent a few days developing more tests in Audio Precision. Work is on-going. Setup is indoor where I actually take pictures of the speakers. Acoustics of the space can impact the measurements naturally but I have worked to minimize them. Feedback is welcome from happy members on this. Grumpy ones please find something else to do.
Let's start simple with linearity test. This is what you are used to in my DAC tests. Since I do not want to go deaf, and there is plenty of noise in my room, the range is quite a bit more limited than when testing electronics. Still, it shows nicely when the speaker reaches its playback limit:
The horizontal scale is calibrated to 96 dBSPL at 1 meter. Our knee in the curve for XT6 is at +16 dB. Adding that to 96 we get a playback level of 112 dB SPL at 1 meter. Yes, I was wearing an ear plug. My wife was not though and complained to be literally getting sick (after I ran the test 20 times to get it all adjusted ).
I hope to build a table for this over time so we can easily track and compare one speaker to another. For now, you can see that the Revel M106 giving up 2 dB earlier at 110 dB SPL.
There is some linear compression in both speakers to the tune of 0.5 dB. It will be interesting to see if this repeats with other speakers.
Let's examine the distortion profile starting with a rather quiet 86 dBSPL at 1 meter:
Our reference Revel M106 clearly has much lower distortion, a difference that it shows much more clearly when we go to the other extreme at 106 dB:
Interesting spikes in distortion in XT 6 around 2.1 kHz or so. It only develops at this high output level:
Something bad is happening around there so perhaps our linearity test is overestimating how clean the speaker can play (linearity is only at 200 Hz).
There has been a lot of requests for intermodulation tests. Alas, AP's IMD tests are designed for electronics and as such, won't allow me to dial down too low of a frequency for the second tone. With default of say, 7 kHz for the upper tone and 60 Hz for the lower, each would be played from a different driver and not show proper intermodulation results.
There is a special test called "MOD" where this restriction is less severe. I was able to play dual tones within the range of the woofer but which tones to use? I picked 85 and 655 Hz:
We see quite a gap here between Revel M106 and Tannoy XT 6. I will have to test a lot more speakers to build confidence in this test and dial the frequencies better.
Finally the test I really liked to run was the spectrum analysis. Here it is for 100 Hz tone:
So quite a lot of harmonics. Conventional wisdom says low frequency distortion is not audible. Is it? Let's overlay threshold of hearing on that:
Naturally harmonics of the 100 Hz extend well into our hearing range where our ears are lot more sensitive. We see that the bars easily exceed the threshold of hearing so they are going to mix with musical detail at low levels and obscure them.
We need to look at masking as well so this is not a complete analysis but there is some smoke here.
I have a lot more measurements but am going to stop here until I develop them more.
Speaker Listening Tests
I looked at the measurements first before listening and expected "bad sound" but such was not the case during my first "5 second" impression. What I was hearing was light to be sure -- indicative of the high frequency emphasis. Audibility was not nearly as bad as I expected however.
I filled in the gaps and knocked down the highs and that definitely helped. But given the theme of this review -- focus on distortion -- I went another way. I still took the highs down. And put in the usual high pass filter to get rid of the most extreme distortions. Latter did the trick as before, nicely improving detail in higher spectrum with no effect on amount of bass. I then added to very sharp notches at dominant distortion points:
Due to our auditory bandwidth being much higher, neither notch filter changed tonality. It did however clean up the notes, getting rid of grunginess and lack of clarity in them. Granted, same thing can happen if you just imagine it so. But I think they are helping and would be something to experiment with.
Before and after made a significant difference, making the speaker less bright and cleaner. Ideal solution would call for additional filters to fill in the gaps.
Conclusions
The Tannoy Revolution XT 6 brings distinct looks to a crowded market which I liked. Objectively though, the coaxial design brought with it a choppy and uneven frequency response which research and my experience shows to not be good. Fortunately the audible effect is not severe. What is severe is level of measured distortion. This distortion in my opinion is audible and serves to produce a distorted sound. Fortunately careful EQ seems to deal with them but then wind up with so many patches to get the speaker to sound right. The designer should have done this, not us.
So overall, I can't recommend the Tannoy XT 6.
------------
As always, questions, comments, recommendations, etc. are welcome.
Yet again I am posting a review way past lunch time and when my sugar reservoir has emptied. I highly suggest if you are going to complain about something, that you donate first to get me in good mood using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
The industrial design of the XT6 is unique with downfiring port that is integrated into the base:
I like it!
While I did not mess with it, I think the angle is adjustable.
This is of course a coaxial design with the tweeter integrated into the center of the "woofer."
Terminals were high quality and easy to turn.
Speaker is designed in UK but manufactured in China. So yes, our scrutiny of UK designed speakers continues.
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 sufficient to compute the sound field of the speaker.
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:
Focusing on the all important on-axis (direct path from tweeter to your ear) we see a couple of significant dips and rising amplitude above 3 kHz neither one of which is good.
On the positive front, directivity -- how close on-axis sound matches what reflects from other surfaces -- is very good with exception of one glitch around 2.5 kHz.
Because of the above, our important early reflections pretty much mirror the on-axis response:
Putting the two together we get our predicted in-room response:
This says you are going to have a somewhat bright sound and with some parts of your music permanently EQed down. The dip in upper bass is most problematic as it is going to take away some "warmth" and detail in bass frequencies. The exaggeration in upper registers may tend to be good in the short term but not so good in longer term.
The jaggies at the end visually are bad but I suspect they are two narrow relative to our auditory bandwidth to be audible as such.
Beam width horizontally is not that wide so suggest toeing in the speaker toward your ear more or less:
Within that +-50 degree window you will have even response though which is good.
Here is the same view in our 3-D map:
We see a nice beam in red but also sections taken out. Former is good, latter not so much.
Vertically the coaxial design comes through showing much better response than typical 2-way speaker:
So maybe if you have bare floors and ceiling that is close, this works better than non-coaxial design, all else being equal (which they definitely are not).
Impedance and waterfall show some resonances that should not be there:
Speaker Distortion Deep-dive:
Avid readers of my speaker reviews know that I am increasingly suspecting distortion plays a role at least in my listening impressions. Research says they play a distant role to tonality which I agree with. But once you have tonality, then I think distortion matters. That is the theory anyway.
To that end, I thought I significantly ratchet up our distortion measurements. Alas, doing so with Klippel NFS is hard. Most distortion measurement features in that system are optional and cost significant money. In addition, they seem to be tailored toward driver measurements than speaker (e.g. wanting me to monitor voice coil temps and such which is not practical in a speaker). Finally, usability is not great because all measurements are optimized for frequency response with asynchronous system (play a full sweep and then analyze).
I am spoiled with my Audio Precision APx555 analyzer which makes such analysis trivial. So I finally broke down and started to use the AP analyzer for speaker testing. But we are getting ahead of ourselves. Let's review our still useful Klippel distortion measurements:
Wow, this speaker wants to produce distortion! Even at 86 dBSPL at 1 meter, it has that peak around 550 Hz and too high of distortion for the rest of the spectrum.
Once we go up to 96 dB, hell breaks loose and we have massive peaks now (right). We are talking 4 to 5% distortion where our hearing is sensitive.
No wonder then that the XT 6 easily exceeds my criteria of 50 dB while playing at 96 dB SPL:
I spent a few days developing more tests in Audio Precision. Work is on-going. Setup is indoor where I actually take pictures of the speakers. Acoustics of the space can impact the measurements naturally but I have worked to minimize them. Feedback is welcome from happy members on this. Grumpy ones please find something else to do.
Let's start simple with linearity test. This is what you are used to in my DAC tests. Since I do not want to go deaf, and there is plenty of noise in my room, the range is quite a bit more limited than when testing electronics. Still, it shows nicely when the speaker reaches its playback limit:
The horizontal scale is calibrated to 96 dBSPL at 1 meter. Our knee in the curve for XT6 is at +16 dB. Adding that to 96 we get a playback level of 112 dB SPL at 1 meter. Yes, I was wearing an ear plug. My wife was not though and complained to be literally getting sick (after I ran the test 20 times to get it all adjusted
). I hope to build a table for this over time so we can easily track and compare one speaker to another. For now, you can see that the Revel M106 giving up 2 dB earlier at 110 dB SPL.
There is some linear compression in both speakers to the tune of 0.5 dB. It will be interesting to see if this repeats with other speakers.
Let's examine the distortion profile starting with a rather quiet 86 dBSPL at 1 meter:
Our reference Revel M106 clearly has much lower distortion, a difference that it shows much more clearly when we go to the other extreme at 106 dB:
Interesting spikes in distortion in XT 6 around 2.1 kHz or so. It only develops at this high output level:
Something bad is happening around there so perhaps our linearity test is overestimating how clean the speaker can play (linearity is only at 200 Hz).
There has been a lot of requests for intermodulation tests. Alas, AP's IMD tests are designed for electronics and as such, won't allow me to dial down too low of a frequency for the second tone. With default of say, 7 kHz for the upper tone and 60 Hz for the lower, each would be played from a different driver and not show proper intermodulation results.
There is a special test called "MOD" where this restriction is less severe. I was able to play dual tones within the range of the woofer but which tones to use? I picked 85 and 655 Hz:
We see quite a gap here between Revel M106 and Tannoy XT 6. I will have to test a lot more speakers to build confidence in this test and dial the frequencies better.
Finally the test I really liked to run was the spectrum analysis. Here it is for 100 Hz tone:
So quite a lot of harmonics. Conventional wisdom says low frequency distortion is not audible. Is it? Let's overlay threshold of hearing on that:
Naturally harmonics of the 100 Hz extend well into our hearing range where our ears are lot more sensitive. We see that the bars easily exceed the threshold of hearing so they are going to mix with musical detail at low levels and obscure them.
We need to look at masking as well so this is not a complete analysis but there is some smoke here.
I have a lot more measurements but am going to stop here until I develop them more.
Speaker Listening Tests
I looked at the measurements first before listening and expected "bad sound" but such was not the case during my first "5 second" impression. What I was hearing was light to be sure -- indicative of the high frequency emphasis. Audibility was not nearly as bad as I expected however.
I filled in the gaps and knocked down the highs and that definitely helped. But given the theme of this review -- focus on distortion -- I went another way. I still took the highs down. And put in the usual high pass filter to get rid of the most extreme distortions. Latter did the trick as before, nicely improving detail in higher spectrum with no effect on amount of bass. I then added to very sharp notches at dominant distortion points:
Due to our auditory bandwidth being much higher, neither notch filter changed tonality. It did however clean up the notes, getting rid of grunginess and lack of clarity in them. Granted, same thing can happen if you just imagine it so.
But I think they are helping and would be something to experiment with.Before and after made a significant difference, making the speaker less bright and cleaner. Ideal solution would call for additional filters to fill in the gaps.
Conclusions
The Tannoy Revolution XT 6 brings distinct looks to a crowded market which I liked. Objectively though, the coaxial design brought with it a choppy and uneven frequency response which research and my experience shows to not be good. Fortunately the audible effect is not severe. What is severe is level of measured distortion. This distortion in my opinion is audible and serves to produce a distorted sound. Fortunately careful EQ seems to deal with them but then wind up with so many patches to get the speaker to sound right. The designer should have done this, not us.
So overall, I can't recommend the Tannoy XT 6.
------------
As always, questions, comments, recommendations, etc. are welcome.
Yet again I am posting a review way past lunch time and when my sugar reservoir has emptied. I highly suggest if you are going to complain about something, that you donate first to get me in good mood using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
