Tidal Akira Stereophile review

[Matt M]

At last, a review of a Tidal speaker! Stereophile has reviewed the Akira:

https://www.stereophile.com/content/tidal-audio-akira-loudspeaker

A few points that stood out to me:

• The ports are tuned to 42Hz. In-room response drops significantly below 40Hz. This appears to be a flat tuning. Average sensivity, quite low considering cabinet size, impedance and the bass extension.
• Appears to be an LR2 topology, with a "2/3" arrangement for the woofers, with the cut-off frequency declining by height. Tidal appears to be very concerned about vertical power response. Crossover frequencies are 250Hz and 2200Hz.
• The off-axis measurements look very good, including the vertical one.
• No LCR-circuit damping the upper spike of the port effects. Don't see a hump, though. Near field measurements would have been nice.
• Allegedly 80lb pounds of gloss-lacquer. 44lb crossover. Didn't find the weight of the cabinet feet again, but same ball-park, weightwise. Crazy, I like that!
• Both impedance and acoustics measurements indicate that they didn't deal with the midrange pipe resonance at 1,2kHz that could also be seen with its -724-brother. Appears to be audible too. Small downer IMHO.
• Tweeter was fried by accident. Not too surprised given the LR2 @ 2.2kHz.

The limited bass extension appears reasonable to me. Still the speaker will need some distance from the walls. Also reasonable for that kind of product. This may not be a LOUD speaker, but it might have very good coherence.

These cabinets are just plain incredible IMO! Like the picture of the crossover being installed. 8O I need this!
-Matt

[Zvu]

I'm gonna get me a cup of coffe, take my laptop and sit comfortably on my couch - this is supposed to be read carefully

[Juhazi]

Sorry I don't undertand "pipe resonance" here. The woofers have passive reflex couplers, no ports at all! I don't like that hig tuning either, preferably just below 30Hz like in large B&Ws. Most PR units are ready for changeable weights for tuning.

To me the most striking feature is smoothest dispersion that I have ever seen published in Stereophile. Even vertically and with a 6" mid. And this is just the "poor man's speaker" model!

[Matt M]

The off-axis is impressive, I agree. Wouldn't have expected that kind of performance judging from the baffle layout.

"pipe (or tube) resonance": the midrange driver is basically a tube. Look at pictures of the ceramic c90-6-0724 to see what I mean. This causes a resonance that has to be dealt with. For whatever reason it cannot be seen in Accuton's measurements, but I have seen other people trying to manage it. E.g. Joachim Gerhard, also Hifi-Selbstbau magazine.

-Matt

[Juhazi]

Oh, you mean this? Backside response looks ugly and looks like cavity resonance yes... https://www.hifi-selbstbau.de/datenb...uton-c90-6-724
Sorry for my bad Deutsch, but how did he fix it? How close did he measure it?

Hinten = backside is red line


And Akira uses a different custom unit, more like 150 (6") https://accuton.com/en-home/produkte/oem-komponenten

[Zvu]

Off axis is really impressive because the acoustic centers are all in the same plain at X and Z axis so there isn't any phase cancellation at crossover points. That's what's so good about Accuton Cell.

[wolf_teeth]

Every Tidal speaker I've heard has impressed me. They know what they're doing.

Later,
Wolf

[Matt M]

but how did he fix it? How close did he measure it?

They measured in 48cm distance. They propose an open cell foam cylinder that is plugged a few centimeters inside the opening.

In the "members only" part of the article they compare different methods of dampening. For the investigation they chose to measure an average of 0° to 60°. Their undampened variant shows exactly the same little hump that is visible in stereophile's measurement which averages 0°..30° at a distance of 50". It is not so evident when one is looking at the on-axis measurement by itself. The latter half of the public article shows their results using the optimized treatment (from "Ab hier alle Messung mit optimiertem Gehäuse (c05) downward).

-Matt

[Juhazi]

The mid must be C90 cell. In Stereophile they say it has diameter of 127mm and outer diameter of C90 is 124mm. Effective driver diameter is 90mm. This is always a problem, some brands and people classify drivers per assembly cutout diameter (might call it nominal), some others by effective.

Wavelength of 1,1 kHz is 31,2cm, 1/4 of that is 78mm, which is pretty close to diameter of C90's voice coil and the cylindrical cavity it makes. So the problem is a 1/4-wave resonance!

To be honest, practically every driver with a voice coil/magnet/spider assembly have turbulence problems and resonances of said structure. Fortunately they are not so bad on the frontside. Usually cone/surround/frame/baffle make much more nasty dips and peaks in response.

[Matt M]

For perspective:

That's an L15RLY in a regular bookshelf speaker. 1/24 octave smoothing and hamming 50%. That's the level of smooth between 1 and 2kHz I would like to see.

I admit it's a compromise how much damping you want to use. And Tidal isn't the only company that seems wanting to avoid too much damping.
Lumen White's Silver Flame comes to mind...

I still find it irrititating, at this price point, and at this level of performance that is shown otherwise. I wonder if one would get any support from Accuton how to use these rather unusual midranges. They should have a recommended remedy in the sleeve, i would expect.

-Matt

[Bukem]

[Zvu]

How does the impedance plot looks with that opening damped ?

[Matt M]

Ahh, great: first-hand experience!

What is it more like: does it "kill the sound" or does it "clean it up"?

[dsrviola]

http://xen-audio.com/documents/accuton/130701%20Accuton%20CELL%20Public.pdf

[5th element]

To me the most striking feature is smoothest dispersion that I have ever seen published in Stereophile. Even vertically and with a 6" mid. And this is just the "poor man's speaker" model!

Really? Most KEF speakers, and any other decent coaxial design, easily have these beaten. And if you deem some directivity control as necessary for good design then they suck!

[5th element]

Off axis is really impressive because the acoustic centers are all in the same plain at X and Z axis so there isn't any phase cancellation at crossover points. That's what's so good about Accuton Cell.

This isn't particularly important and is only marginally useful for the horizontal off axis performance. Good phase integration should be managed at the crossover level regardless of the driver arrangement. Sure it probably helps a little, given the right crossover frequency and slope type, but for the most part it's largely marketing fluff.

[Zvu]

For every other speaker, you design a crossover with best phase and amplitude response for a specific axis and you try to keep off axis phase integration as best as you can because Z offset is varying. With Cell drivers the phase integration looks the same for a much wider measurement window (if directivity is taken into account when designing the crossover as here obviously is). How is that marketing fluff ?

[Juhazi]

5th, here is KEF Reference 5 for comparison https://www.stereophile.com/content/...r-measurements


Yes, very smooth hor and vert dispersion! But the main difference is directivity profile - increasing towards treble. This is good for imaging at hot spot, but not so good for tonality and off-spot. Quite a lot a matter of personal taste which combination suits you, Sir. I am more in favour of wide dispersion and positioning the speakers on the long wall in the room.

Here room response around the spot, red is R5 and blue KEF Blade2, which is more like what I prefer.



And here Akira (red) and Wilson Alexia2 (blue) in same room

[Matt M]

Yes, very smooth hor and vert dispersion! But the main difference is directivity profile - increasing towards treble. This is good for imaging at hot spot, but not so good for tonality and off-spot. Quite a lot a matter of personal taste which combination suits you, Sir. I am more in favour of wide dispersion and positioning the speakers on the long wall in the room.

+1

For every other speaker, you design a crossover with best phase and amplitude response for a specific axis and you try to keep off axis phase integration as best as you can because Z offset is varying. With Cell drivers the phase integration looks the same for a much wider measurement window (if directivity is taken into account when designing the crossover as here obviously is). How is that marketing fluff ?

Also: +1.

This isn't particularly important and is only marginally useful for the horizontal off axis performance.

The argument that phase tracking under vertical angles will still be bad, is sound. However, maintaining on-axis phase coherence over a wider frequency range is beneficial. Maybe "marginally" - we could argue about that. Having aligned SEOs is a cleaner solution in this regard than twisting the crossover slopes. From a theoretical perspective - and I believe relevant in practice too. That's part of what Sten Duelund was about with his coherent multiway filters: coherent up to -40dB below summed response!

-Matt

[5th element]

For every other speaker, you design a crossover with best phase and amplitude response for a specific axis and you try to keep off axis phase integration as best as you can because Z offset is varying. With Cell drivers the phase integration looks the same for a much wider measurement window (if directivity is taken into account when designing the crossover as here obviously is). How is that marketing fluff ?

Because the change in the vertical off axis response, ignoring drivers beaming, is due to the change in path differences between the midrange and tweeter as the microphone height (or ear height) changes. This change is the same regardless of whether or not you are using Cell drivers, or conventionally mounted drivers. The change in path differences, between the two drivers as the mic shifts, results in a change between their phase relationship and you get the typical nulls appearing.

Cell does nothing to combat this.

The only way to improve this is to mount the drivers closer together, or go co-axial.

All the Cell thing does, vs a standard driver, is change the starting Z axis, ever-so-slightly, of the midrange driver, but that's it. This may help with the initial phase integration of the midrange and tweeter, on the specified design axis, but it could also make it worse! It depends entirely on what the designers intended design axis, filter slopes, xover point and overall design ideas are.

[5th element]

5th, here is KEF Reference 5 for comparison https://www.stereophile.com/content/...r-measurements

This is good for imaging at hot spot, but not so good for tonality and off-spot. Quite a lot a matter of personal taste which combination suits you, Sir. I am more in favour of wide dispersion and positioning the speakers on the long wall in the room.

My ears don't like direct radiators, but they do like controlled directivity.

You see the thing here when you say this...

but not so good for tonality and off-spot

How far off axis are you actually wanting to go? Wave-guide systems will typically maintain a smoother off axis response, within typical listening angles, and give you less tonal shift than direct radiators. The same is true for imaging, where a correctly configured set of wave-guide speakers, will actually correct for off centre seating positions. Hardly anyone actually sets their wave-guide speakers up correctly though to allow for this.

http://www.libinst.com/PublicArticles/Setup%20of%20WG%20Speakers.pdf

With a wave-guide if you go a decent distance off axis you're going to get less high frequency energy thrown out. But that is the point of controlled directivity, ie to throw far less sound out, towards the reflective walls of the room, and therefore have fewer early reflections to smear the imaging of your system. They are designed to be used without any room treatment and should not be used in conjunction with it. Direct radiators often require significant room treatment to control those earlies and to soak up excess high frequency energy, otherwise your imaging suffers. Room treatment will add a downwards tilt to the balance. If you're going to use a wave-guide speaker, remove your room treatment.

It's also worth pointing out that the link of the KEFs off axis response goes all the way out to 90 degrees, whereas the Akira only goes out to 45 degrees. The KEFs have a comparably less affected off axis response when you take that into consideration. The only issue that you appear to have is the slight difference in top octave tonal balance. Well this is something that should be corrected for, for personal preference, with tone controls, as it's determined entirely by your room, not the designer of said speaker.

[Zvu]

Because the change in the vertical off axis response, ignoring drivers beaming, is due to the change in path differences between the midrange and tweeter as the microphone height (or ear height) changes. This change is the same regardless of whether or not you are using Cell drivers, or conventionally mounted drivers. The change in path differences, between the two drivers as the mic shifts, results in a change between their phase relationship and you get the typical nulls appearing.

Cell does nothing to combat this.

The only way to improve this is to mount the drivers closer together, or go co-axial.

I wasn't talking about vertical dispersion (i didn't write horizontal either for that matter so i understand where confusion comes from) because i consider it to be quite unimportant if driver directivity is taken into consideration when designing crossover for linear horizontal on and off axis frequency response. With Nd tweeter and 5" midrange crossed at 2.2KHz mounted as close as Tidal did it, vertical lobe is more than enough high not to present an issue.

I'm listening my R300 that are coaxial and compare it to Technocracies which are standard configuration - tweeter above midwoofer. I never heard anything better coming from R300 that i could attribute to its coaxial mid-hi driver and its better vertical directivity, so for me it is quite irrelevant.

If i was jumping around the room while listening for how well the crossover integration is, that would be quite different i presume

...All the Cell thing does, vs a standard driver, is change the starting Z axis, ever-so-slightly, of the midrange driver, but that's it. This may help with the initial phase integration of the midrange and tweeter, on the specified design axis, but it could also make it worse! It depends entirely on what the designers intended design axis, filter slopes, xover point and overall design ideas are.

With Cell drivers the acoustic centers of all drivers are on the mounting plane so when you design flat frequency response and good phase response on axis, the reverse polarity dip will remain the same to extreme horizontal off-axis angles (given that there is no offset at X axis). It will not get deeper or shallower as is the case with other random drivers. With other drivers you design frequency and phase response for a specific horizontal axis angle while with Cell you design it for the whole horizontal listening window.

[Juhazi]

5th element, I want to have same spectral balance also at the dinner table and in the kitchen and corridor, only the cold spot in the toilet may suffer a little! You have totally different idea of listening area.

Because of this 3D sound dispersion gets important and this is why I like my dipoles so much. Omnis and almost omnis like Devialet Phantoms come close to this too. Another example of wide dispersion is Vivid Giya, but I haven't heard it. B&W speakers have very uneven disperion, but quite wide. Upper treble is a problem that can be helped with a backside tweeter like many high-end large speakers have, eg. SF's new top model Aida.

KiiAudio Three is a special speaker with uniform cardioid dispesion. I haven't heard it but for sure it has real potential to keep sound balance even also far off axis in a room. Gradient Labs of Finland hs some extraordinary models too like 1.4, Revolution and Helsinki 1.5

The special feature of (well done) dipoles is that radiation sideways 45-135 degrees is highly attenuated and thus they image better than omnis. But these are rare animals, most dipoles have too wide and uneven dispersion from 2kHz up.

Measurements of 3D soundfield of loudspeakers at Princeton University https://www.princeton.edu/3D3A/Directivity.html

[5th element]

With Cell drivers the acoustic centers of all drivers are on the mounting plane so when you design flat frequency response and good phase response on axis, the reverse polarity dip will remain the same to extreme horizontal off-axis angles (given that there is no offset at X axis). It will not get deeper or shallower as is the case with other random drivers. With other drivers you design frequency and phase response for a specific horizontal axis angle while with Cell you design it for the whole horizontal listening window.

That doesn't really help you in any way though surely? The drivers acoustic centres might be in line with the mounting plane, but they are all separated by a considerable distance within the Y axis. As a design axis you place the microphone in line with the tweeter and you're 1 meter away from it. With a 16cm c2c distance you've got a path difference of ~1.3cm. So with the cell drivers you've theoretically got to account for 1.3cm worth of Z plane offset in your crossover. Using a conventional driver this might be 2.3-3.3cm of Z plane offset depending on the drivers. In either case you've had to account for a degree of offset in the design.

If you now start taking horizontal off axis measurements of both systems these Z plane offsets will remain exactly the same, so I don't see how having the Cell drivers is going to improve things? You aren't going to get additional phase shifts for either system regardless of where you place the microphone. What will happen are typical off axis response changes, both drivers will suffer from diffraction effects, both from the drivers themselves and the cabinets they are placed in and then you're going to have the usual off axis response changes that you'd expect from cone/dome drivers.

This also goes back to what Matt was saying above about maintaining accurate slope tracking down to -40dB or so (accurate slope tracking is going to shape the off axis nulls too). Cell isn't really going to help here as -40dB down you're going to be almost 2 octaves away from fc with a typical 4th order slope. This would require drivers with on and off axis responses that are identical out to 2 octaves above/below fc. This has nothing to do with the Cell system though as the Z plane off sets remain identical regardless of horizontal off axis angle. The Cell system might allow you to use slightly less asymmetry, in a typical passive crossover, for your given design axis, but the gains from this are going to be completely swamped out by the response changes brought about by diffraction and the drivers own natural off axis response, let alone passive crossover component tolerances.

[5th element]

5th element, I want to have same spectral balance also at the dinner table and in the kitchen and corridor, only the cold spot in the toilet may suffer a little! You have totally different idea of listening area.

Because of this 3D sound dispersion gets important and this is why I like my dipoles so much. Omnis and almost omnis like Devialet Phantoms come close to this too. Another example of wide dispersion is Vivid Giya, but I haven't heard it. B&W speakers have very uneven disperion, but quite wide. Upper treble is a problem that can be helped with a backside tweeter like many high-end large speakers have, eg. SF's new top model Aida.

KiiAudio Three is a special speaker with uniform cardioid dispesion. I haven't heard it but for sure it has real potential to keep sound balance even also far off axis in a room. Gradient Labs of Finland hs some extraordinary models too like 1.4, Revolution and Helsinki 1.5

The special feature of (well done) dipoles is that radiation sideways 45-135 degrees is highly attenuated and thus they image better than omnis. But these are rare animals, most dipoles have too wide and uneven dispersion from 2kHz up.

Measurements of 3D soundfield of loudspeakers at Princeton University https://www.princeton.edu/3D3A/Directivity.html

I don't know about you but my wave-guide speakers sound awesome in the corridor outside of the room they are in and in the rooms connected to it!

Your dipoles, on the other hand, are going to have huge nulls off axis. Their form of directivity control helps with room integration but only for a much smaller listening window than a wave-guide design. Go off axis and you'll start to sit in a null and with far off axis, at a decent listening distance (say being in the kitchen) resulting in a chaotic spray of coherent and incoherent sound thrown all over the place. How is this a good thing for a uniform tonal balance wherever you choose to listen?

[Zvu]

That doesn't really help you in any way though surely? The drivers acoustic centres might be in line with the mounting plane, but they are all separated by a considerable distance within the Y axis. As a design axis you place the microphone in line with the tweeter and you're 1 meter away from it. With a 16cm c2c distance you've got a path difference of ~1.3cm. So with the cell drivers you've theoretically got to account for 1.3cm worth of Z plane offset in your crossover. Using a conventional driver this might be 2.3-3.3cm of Z plane offset depending on the drivers. In either case you've had to account for a degree of offset in the design.

If you now start taking horizontal off axis measurements of both systems these Z plane offsets will remain exactly the same, so I don't see how having the Cell drivers is going to improve things? You aren't going to get additional phase shifts for either system regardless of where you place the microphone. What will happen are typical off axis response changes, both drivers will suffer from diffraction effects, both from the drivers themselves and the cabinets they are placed in and then you're going to have the usual off axis response changes that you'd expect from cone/dome drivers....

Cell drivers are strange beasts so they demand a bit unorthodox approach. I would never place microphone on the tweeter axis to make it the design axis but in the middle, between acoustic centers of midrange and tweeter. That way i get isosceles triangle at mic position and there is no offset going horizontal off axis whatsoever.

....This also goes back to what Matt was saying above about maintaining accurate slope tracking down to -40dB or so (accurate slope tracking is going to shape the off axis nulls too). Cell isn't really going to help here as -40dB down you're going to be almost 2 octaves away from fc with a typical 4th order slope. This would require drivers with on and off axis responses that are identical out to 2 octaves above/below fc. This has nothing to do with the Cell system though as the Z plane off sets remain identical regardless of horizontal off axis angle. The Cell system might allow you to use slightly less asymmetry, in a typical passive crossover, for your given design axis, but the gains from this are going to be completely swamped out by the response changes brought about by diffraction and the drivers own natural off axis response, let alone passive crossover component tolerances.

I do admit that i'm overwhelmed by design and performance of Cell (C90-6-724 in particular). I wouldn't use standard LR4 with Cell drivers but Richard Modaferri's elliptic (also known as cauer and/or infinite slope) filters. I'd definitely try to minimize all other degradation factors in the design because i think that drivers deserve it. That being said, i don't believe i'm ever gonna be able to afford them - even in standard version, let alone some upgraded ones.

[Juhazi]

5th, I can't hear those interferences because of the meyhem of them. But they sound good far away! And I can't hear the side-nulling indoors either (unless closer than 1 ft), because my brains use so long IR gating!

Obviously you don't use very wide and deep wgs. Or you have rather high RT values, hard walls in your apartment. My RT30 is around 0.4, EDT 0.2-0.3 and living room is 3,5x6m, tilted wooden ceiling, gypsum board walls. But I have naturally heard synergys and 15" coaxes in different rooms, not at my home (never over my body)



That is a 55" TV!

[5th element]

Cell drivers are strange beasts so they demand a bit unorthodox approach. I would never place microphone on the tweeter axis to make it the design axis but in the middle, between acoustic centers of midrange and tweeter. That way i get isosceles triangle at mic position and there is no offset going horizontal off axis whatsoever.

Yes of course, for the design axis, but we all know that no one actually listens exactly on that axis, or at least we prefer not to have our head in a vice! Of course both you and I have gone to coaxials for their obvious advantages and I never intend on looking back!

[5th element]

5th, I can't hear those interferences because of the meyhem of them. But they sound good far away! And I can't hear the side-nulling indoors either (unless closer than 1 ft), because my brains use so long IR gating!

Obviously you don't use very wide and deep wgs. Or you have rather high RT values, hard walls in your apartment. My RT30 is around 0.4, EDT 0.2-0.3 and living room is 3,5x6m, tilted wooden ceiling, gypsum board walls. But I have naturally heard synergys and 15" coaxes in different rooms, not at my home (never over my body)

Well if you stepped directly into an actual null you'd surely hear it, but as you said the overall chaos and room interaction covers it up. Yes I'm not talking about massive wave-guides like those. Just something in line with the KEFs. I use the B&W FST driver as my midrange, modified with the phase plug removed + small tweeter to turn it into a coaxial. This gives me a 15cm waveguide, it measures incredibly well, but obviously doesn't have as much pattern control as something that's 15" in diameter. Even this size is enough to make my ears happy vs naked domes.



I was more trying to say that I don't think the off axis response, of the KEFs you linked above, would sound uneven or vastly different wherever you are in your listening environment (obviously within reason). And yes, my room uses zero room treatment without any extravagant furnishings. There is a carpet and curtains though. The advantage of the wave-guides, though, is that they lessen the immediate impact from the room.

[Zvu]

I guess that guys from Tidal realised they have to eat something. They founded subsidiary called Vimberg with look alike of their Akira model, and there is smaller one with 6" woofers.

http://www.theaudiobeat.com/highend2018/highend2018_tidal.htm

When i read that when they mention 23000 euros they also mention the words "cheap", "bargain" etc., it makes me wonder - are those reviewers on heavy drugs ? They are comparing it to already ridiculously priced Akira (180.000). La Assoluta i get - someone said "i'm gonna build the most expensive loudspeaker in the world" and that's not new, it's a marketing trick and is understandable. He did it so everybody that can't afford it would buy Akira. Now he uses the same carrot on a stick for the guys who are willing to pay 23000 for the smallest model.

Revel Ultima Salon 2 measures much much better than Akira and costs 22000 usd a pair - cheaper than Tidal's cheapest model Mino.

[Juhazi]

Vimbergs look like well done speakers anyway, despite of being "cheap as soap".
Yes, Revel's top model measures well, but tweeter's directivity jumps fast above 10kHz. It is partially compensated by elevated on-axis response. Very good room response, but measured in a different room than the speakers that I linked earlier here.


One thing not said here is that these big and expensive speakers usually go to large living rooms (so that guest will see them). They get room to breathe the low bass notes and walls are far away to give good imaging despite of wide dispersion. It is actually very nice to have different types of loudspeakers available for different rooms and tastes. Just takes some understanding to make good choices.

[Zvu]

Hi-end is so ridiculously expensive that Revel Ultima Salon 2 looks cheap beside Akira. And if tweeter dispersion is the only thing that is better in Akira i have a few dirth cheap (not really, 5000-7000 usd) speakers that will nail it, along with ruler flat frequency response and lack of any driver resonances in their passband. Oh yeah, and you can't buy a decent motorcycle for the price of their crossover.

If wide dispersion is name of the game Revel Performa F208 will do it for 5000$.

I'd really like to see more of blind tests and what loudspeakers would win it - expensive and big or well engineered no matter the cost.

[5th element]

Revel Ultima Salon 2 measures much much better than Akira and costs 22000 usd a pair - cheaper than Tidal's cheapest model Mino.

Yeah Revel always design with purpose and good engineering, the same with Kef and a few others out there.

I mean with the Akira they did set out to make a statement and that statement costs a fortune. It isn't really a surprise when you actually look at the cost of the Accuton units within. The diamond dome tweeters are around $3500 per pair. The 2" version of the diamond mid would cost $11000 per pair. The 5" cell diamond that they've customised could cost $40,000 per pair for the huge amount of diamond needed for the diaphragm. The bass units are around $600 per driver and the passive radiators will set you back $350 each.

You're looking at $50,000 in drivers alone. Or something roughly similar.

I don't think there's anything actually wrong with the Akira, for a standard naked cones/domes speaker it's close to as good as it gets. I would have preferred that they went with a diamond version of the C173-6-096E as that 5" cell driver has problems. That would cost even more though.

To be fair I think a better product would be the 1" diamond dome + 2" diamond dome as the mid/tweeter top. Then cross the 2" to the upper bass driver at ~800Hz. Cross the thing as a 3.5 way with suitably designed bass drivers, so that only the upper of the three bass drivers covers the lower midrange and all three handle all the bass.

It's a ridiculous speaker either way. Most of the money being spent on ridiculous drivers that cost a fortune. That's sort of the point of the speaker though and if I was nitpicking I'd want to go one step further. Probably something like 1" diamond dome + 2" diamond dome + diamond C173-6-096E then bass drivers. Do away with that terrible 5" cell midrange. Of course you could drop the 2" diamond dome and push the 1" diamond dome hard, crossing it directly to the C173-6-096E diamond. Then you'd really have a ludicrous speaker. For an improvement wave-guide load the 1" tweeter, a la Revel, and you'd really be in business.

The trouble with this ludicrous is that you could essentially do this - 1" SB ceramic dome + custom 5" aluminium cone Satori driver + 3x custom aluminium cone MW19Ps (7.5" bass driver) and custom passive radiators. Instead of costing $50,000 for the drivers, you'd be looking at $3000. Suitably crossed over it would perform exactly the same, and with lower HD, as the Satori motors are the best in the business at the moment. There is simply no need to go the route that Akira have, but then you wouldn't be able to brag about a 14 carat diamond midrange driver.

[5th element]

Vimbergs look like well done speakers anyway, despite of being "cheap as soup".
Yes, Revel's top model measures well, but tweeter's directivity jumps fast above 10kHz. It is partially compensated by elevated on-axis response. Very good room response, but measured in a different room than the speakers that I linked earlier here.


One thing not said here is that these big and expensive speakers usually go to large living rooms (so that guest will see them). They get room to breathe the low bass notes and walls are far away to give good imaging despite of wide dispersion. It is actually very nice to have different types of loudspeakers available for different rooms and tastes. Just takes some understanding to make good choices.

The room wont have a huge amount to do with it at proper gated measurements are being used for the upper portion of John Atkinson's measurements. These filter out the room.

I will repeat it once more though that the off axis response of the Akira, that you showed above, only goes out to 45 degrees. It looks impressive when viewed next to most of stereophiles other off axis measurements because they go out to 90 degrees, just like the Revel measurement does.

[Juhazi]

This is the room response of Revel Salon2 I was talking about, not the normalized directivity plot. And ofcourse I was supposing that the reader will look at scales of directivity graphics, like always! Perhaps I take it too granted because of my academic education.

[5th element]

This is the room response of Revel Salon2 I was talking about, not the normalized directivity plot. And ofcourse I was supposing that the reader will look at scales of directivity graphics, like always! Perhaps I take it too granted because of my academic education.

What's wrong with that?

[Juhazi]

^Nothig wrong with it, I quote myself:
"Very good room response, but measured in a different room than the speakers that I linked earlier here."

Please let me clarify that I know that Stereophile's directivity measurements are done with short gating and they are reliable. I have never questioned that. They often publish also room response, which is average of 120 measurements in either editor's or Atkinson's room. Room response has long gating and it sort of combines the listening window and total power response of the speaker and reflections in the room.

Atkinson tells very openly how he measures loudspeakers for Stereophile. I find his measurements relevant and reliable, only distortion test is lacking.

https://www.stereophile.com/features/99/index.html

https://www.stereophile.com/features/100/index.html

https://www.stereophile.com/features/103/index.html

ps. One more thing about Akiras that I like - LR2 crossovers and tight and clean step response!

[Kal Rubinson]

^Nothig wrong with it, I quote myself:
"Very good room response, but measured in a different room than the speakers that I linked earlier here."

Please let me clarify that I know that Stereophile's directivity measurements are done with short gating and they are reliable. I have never questioned that. They often publish also room response, which is average of 120 measurements in either editor's or Atkinson's room. Room response has long gating and it sort of combines the listening window and total power response of the speaker and reflections in the room.

Here are the responses from two rooms.

[wkhanna]

i have heard a range of Tidal speakers from visiting the audio shows, just back form CAF a few weeks ago where i again heard multiple Tidal offerings.

i realize you guys want measurements so you can build to the same result, but once you have heard Tidals, you will have no interest in how they measure.....
they always blow me away.... especially when in the company of Brian Zolner, owner of Bricasti...

jmho ymmv

[kimmosto]

..I have gone to coaxials for their obvious advantages and I never intend on looking back!

Coaxial makes one basic thing right at upper mid...lower treble but it does not guarantee high quality. "Quite okay" for casual listening is easy to get but potential limit of the driver is not necessarily very much higher than that.

[5th element]

Coaxial makes one basic thing right at upper mid...lower treble but it does not guarantee high quality. "Quite okay" for casual listening is easy to get but potential limit of the driver is not necessarily very much higher than that.

Well obviously. You need to make sure that you've crossed your T's and dotted your I's with the design.

The same can be said for any speaker though. Pick the wrong drivers or miss-use them and you'll only end up with mediocrity.

[kimmosto]

Pick the wrong drivers or miss-use them and you'll only end up with mediocrity.

Everything is some kind of compromise. We wouldn't have so many multi-ways with separate M+T drivers if good enough coaxials exist for most of the listeners and manufacturers. Individual requirements could be quite focused to something else than individual off-axis responses in vertical plane. If those requirements are not fulfilled with available component, that driver type is out of the game.
I can tolerate and design with or without commercially available coaxials, but separate drivers enables higher overall quality with my preferences.