Kurosawa Koncept System

[Fdas]

Placement is important to get the most out of them- just listen to what Bob, Dar, and Ron say after I sweet talk them into an afternoon's experiment to set them up "right"...

The only other solution would be to develop what I would call a studio mount version- that is, one designed for flush wall positioning, at ear level or above. This is quite possible to do, and it could also easily handle that mythical center channel Ardent functionality... in this case, the woofers would flank the midrange/tweeter elements operating as a vertical set, and no baffle step compensation would be used. The interesting question would be the geometry of the whole thing- designed to set on a shelf? Flush the ceiling and tapered relative to the wall, aiming downwards? There are several possibilities. Now imagine the challenge if one did that with a dual AS190 system, just PR's on the sides... problem with the AS190 is that due to T/S parameters you need a largish enclosure- what I suspect these Dai Katana's are so large. Using the Wavecor Ardent driver set would make it easier, for certain. PR's optional.


Hmmm.

Sounds like an interesting project. If something like this ever develops and there is some initial 'mass production' of cabinets like the Ardents, I would certainly be interested.

[TEK]

Was that a rumor about a Ardent center I just heard?:dancenana::dancenana:

[JonMarsh]

And I know just the guy to hire and sub contract some CAD cabinet work too...


Paging Stephen Manning, paging Stephen Manning, Please report to the Kurosawa Thread...


My apologies, Evil Twin, for diverting the content of your thread... I hope an apology like Captain Needa's won't be needed in this case...

[BobEllis]

Placement is important to get the most out of them- just listen to what Bob, Dar, and Ron say after I sweet talk them into an afternoon's experiment to set them up "right"...

We just took down the tree and put my Ardents back out in the room. Without my saying a word, my girlfriend commented that "The sound is much more spacious. With the speakers against the wall the sound was much flatter." And that's only a couple feet out, nowhere near as good as the Cardas positioning.

[Horio]

Was that a rumor about a Ardent center I just heard?:dancenana::dancenana:

I think it might have been.

I have a rather large collection of classical SACD's (5.1 channel) and I've been hoping a ardent center of sorts might develop while I slowly work on my ardents.

[Steve Manning]

And I know just the guy to hire and sub contract some CAD cabinet work too...


Paging Stephen Manning, paging Stephen Manning, Please report to the Kurosawa Thread...


My apologies, Evil Twin, for diverting the content of your thread... I hope an apology like Captain Needa's won't be needed in this case...

You rang ...... hone:

[wkhanna]

... I have an associate who has listened to the Tidal Audio Akira at length at their factory with material we are both familiar with and can replicate here- if in his judgment they are even vaguely similar in capabilities and characteristics, then producing some facsimile of the experience at 1/13 the direct expense, plus a large portion of sweat equity, will likely have made the effort worthwhile.

we spend hours every year at Capital Audiofest listening to Tidal speakers.
most notably the Piano & SunRay.

[JonMarsh]

You rang ...... hone:

Email headed your way... :B

[JonMarsh]

But what do you think of them?

we spend hours every year at Capital Audiofest listening to Tidal speakers.
most notably the Piano & SunRay.

But Bill, what do you think of them? I hear guys at Guantanamo Bay spend hours every day getting water boarded (or will with the new President Elect), but I'm not sure they recommend the experience... :W


Note, these are the official Stephen Manning approved Tidal Audio Designs, with the passive radiators on the SIDE, where God intended them to be! :B

[Zvu]

I'm soooo jealous of you right now

we spend hours every year at Capital Audiofest listening to Tidal speakers.
most notably the Piano & SunRay...

[Evil Twin]

New Augmented Reality capabilities?

One picture to post today - it reveals the hidden built in photoshop capabilities for inserting reflections, only available in the Jet Black iPhone 7+... (this variation of the iPhone was originally known as the "Vader Special" in the Cupertino labs while in development...)

Augmented reality?

No, the second cabinet is actually progressing nicely now... It is remarkable how much more progress one makes when actually working...

[wkhanna]

But Bill, what do you think of them? I hear guys at Guantanamo Bay spend hours every day getting water boarded (or will with the new President Elect), but I'm not sure they recommend the experience... :W

oh, it is definitely an experiance i most highly recommend......Tidal, that is, not the waterboarding.......though with the Syrian blood that runs in my veins, i wonder if soon i may involuntarily experiance that, too.... :rofl:

Note, these are the official Stephen Manning approved Tidal Audio Designs, with the passive radiators on the SIDE, where God intended them to be! :B

the SunRay's truly are a wonder to behold.....the only speaker i have heard that truly reproduces a believable level of bass one hears from a symphony orchestra along with the hall ambiance.

as for the Piano's, well, i will offer up an educated guess based on the many, many speakers i have heard over the years that they may approach (not meet) the same level of accuracy as one of The Maestro's master designs.
this belief is based on Jon's superior network design & the fact that he is not limited by commercial production restrictions in component selection & cost.

i promise myself one day soon, i will hear the Ardent.......even if i have to build the damn things myself.....:M

[wkhanna]

Augmented reality?

the reality is i can count each individual thread :E:T:B

[TEK]

One picture to post today - it reveals the hidden built in photoshop capabilities for inserting reflections, only available in the Jet Black iPhone 7+... (this variation of the iPhone was originally known as the "Vader Special" in the Cupertino labs while in development...)

Augmented reality?

No, the second cabinet is actually progressing nicely now... It is remarkable how much more progress one makes when actually working...

That's an impressive level of craftsmanship. Well done!

[cochinada]

... This design fully supports a time aligned Duelund crossover design, which only has one phase rotation of 180 degrees between 20Hz and 20kHz, and for which the drivers are always at any frequency in the same relatively phase. This is made possible by the Accuton Cell driver construction, with the acoustic origin in the mounting plane. Will this have a meaningful impact on the subjective performance? Only time will tell, but it is telling that Accuton is ONLY putting development resources for new drivers into the Cell concept, and the newest designs from European companies are heavily focused on these new drivers.

The driver distortion is very low, especially so for the AS190 woofers, and also 3rd harmonic for the 7140 Beryllium tweeters. So there is a clear objective improvement in that regard.

The design is a relatively tall source in the low frequencies, which also tends to make for a more uniform bass performance and lowers the impact of floor bounce irregularities in the upper bass and lower midrange. Perhaps the technological terror that this design and construction represents will have pay offs greater than those of the previous flawed and failed battle stations. Only time will tell...
..."

I've been following this with great interest but one thing puzzles me. If you are using the tweeter from ScanSpeak how can you be certain it has the acoustic origin at the mounting plane like the Accuton Cell drivers do? Shouldn't you have used a Cell tweeter as well? :huh:

[Evil Twin]

I've been following this with great interest but one thing puzzles me. If you are using the tweeter from ScanSpeak how can you be certain it has the acoustic origin at the mounting plane like the Accuton Cell drivers do? Shouldn't you have used a Cell tweeter as well? :huh:

Ah, but you see, it is tweeters in general that set the standard for an acoustic time orgin in the mounting plane- you could select a handful or double handful of tweeters, and do an impulse test on them, and the results would be quite similar as regards time of flight and origin- whether ScanSpeak or Accuton- whereas the matter is quite different when you factor a midrange driver or woofer into the picture-

In general, exact origin depends somewhat on the location of the voice coil gap, but greatly on the attachment method and location to the radiating cone, and the stiffness/propagation characteristics of the voice coil and cone.

So dome tweeters driving at the edge of the dome, with a fieldplate near the surface of the driver and a very shot voice coil assembly set the origin for all practical purposes at the surface of the baffle. A midrange or woofer driver with the voice coil 2-3" behind the front panel may have an effective original somewhere near where the VC connects to the radiating cone. The stiffer the VC and the cone, the more likely it will work out this way. The best way to determine this and account for issues (if possible) in the crossover design is by testing each driver individually, and testing with all driving simultaneously, and in a program like LspCAD, adjust the time offset values of the individual drivers until the overall response matches what was measured for the individual drivers.

note, if you setup carefully, and have a program that reports the complete delay on impulse from the test time of flight, you can get a fairly close idea by setting up and measuring each driver sequentially.


Two key methods are employed in the Accuton cell midranges and woofers.

For the midranges, the periphery of the inverted hemispherical dome are driven, not the rear- regardless of size, so the driving point is consistent- and a very stiff titanium voice coil is used, so the exact offset of the field plate gap is not critical or even very relevant.

With the woofers, it is different- though due to the lower frequencies, a small time delay has minimal impact on phase alignment. For the woofers, an hemispherical dome is again used, but NOT inverted- and the cone is driven at the center of the cone, which is actually forwards of the mounting plane. OTOH, a long titanium voice coil has to be used, as a somewhat a conventional magnetic structure is still used. But the effects combine to put the origin in the mounting plane, and incidentally to give very good off axis dispersion compared with conventional cone geometries of the same size (about 8", 22cm).

[cochinada]

Thanks for the explanation. The things you know...
Then I have one more question if I may: if I'm understanding your project well you are going to mount the midrange and the tweeter on this elevated baffle piece. How do you account for that? For sure now those three woofers are on a different plane and acoustic center compared to the others or not?

P.S. I think you are not using Sketchup for the design of the cabinet. Anyway on my spare time I draw the AS190-9-252 and also the PR223BD02 and I'm sharing if anybody wants to 'play' with them. It's my small contribution for this community that is always so helpful and knowledgeable.

NOTE: both models were saved on Sketchup Make 2017.

Image not available

Image not available

EDIT: I forgot I have also the D2908-714000:

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They are all in scale 10:1

[Evil Twin]

The midrange tweeter plate is not thick, and the tweeter mount is routed through nearly all the way. The mounting fixture for the midrange Cell driver from Accuton is used behind behind that panel, mounted on the main front panel, and it's design allows adjusting the time offset of the midrange to the tweeter if needed. The woofers have a very shallow rebate, and at the frequencies of the woofer and midrange overlap, if the time alignment is off by 1/4", it is a relatively minuscule phase difference.

Thank you for preparing the driver models- I can readily export them from SketchUp Pro Pro to formats which my tools can read (Fusion 360, Shark FX).

[fish fingers]

http://weidlich-audio.de/amur-series-1.html

Thought this may be of interest- an audible vibration from the C90's grill. No idea at which frequency but this designer felt the need to add a 'damper'

[Face]

Flick the C220's grill and you will hear a really nice resonance.

Sent from my SM-G935V using Tapatalk

[Zvu]

[fish fingers]

Those tidal's are really working that little midrange too much imo. I read its crossed at around 150hz

Sent from my SM-G950F using Tapatalk

[Zvu]

I hear ya. But then again i never listened midrange with a cone that's rigid as that one and when such experienced guy as Atkinson is impressed and starts talking - i choose to listen. Measurements will show us one part but he is genuinely impressed by the sound - if it's not an act of courtesy. I do hope Akira finds its way into Stereophile testing facility aka Johns room.

My real concerns goes into direction where 6000Hz is the upper crossover point. That's why i'd like to see those off axis measurements.

[fish fingers]

I hear ya. But then again i never listened midrange with a cone that's rigid as that one and when such experienced guy as Atkinson is impressed and starts talking - i choose to listen.

My real concerns goes into direction where 6000Hz is the upper crossover point.

The ceramic version has a 3rd harmonic spike around 2900hz, beaming I guess around that point too. No idea if this 'diamond' version is any different, apart from the cone.
+1 on stereophile, really enjoying the recent videos

Sent from my SM-G950F using Tapatalk

[Evil Twin]

I am inclined to agree with the comments regarding the frequency span for which they're using the diamond midrange driver-

While I expect that the diamond dome will push the break up modes and distortion amplification corners up by at least one octave, there is no ready way to improve the dispersion pattern from that size radiator- while a 2" driver would perform well at 6 kHz and slightly beyond, a 4" diaphragm is another matter.

It is rumored that there are motor improvements for the Akira version, perhaps these improve the distortion at the low end. The standard version is no slouch compared to many other companies's products, but it is not the best performer from Accuton, and should benefit from using a higher crossover point, especially depending on the type and slope of crossover. Additionally, the standard construction of the basket leads to a tunnel resonance, shown clearly at about 1250 Hz in the crossover page below; these were eliminated with additional modifications to the drivers. Note also that the measured AS190 response below is without passive radiators, but instead a simple sealed box.

The crossover choices should always be made fully cognizant of the driver performance realities...




The current status of this project is equivalent to being frozen in carbonite; all items preserved and ready for re-animation at a time when the press of Imperial intrigue and personal matters allows spending time on them. Realistically, I am not in favor of loading the drivers in the cabinets until they are in the final location for intended use- that could be two or more years away. But building and testing crossover modules and some other functions may continue at some time later this year, perhaps even loading all drivers, but reserving removing the woofers for final transport.

Much is yet to be determined based on pending events- as Yoda might say, there are so many alternate decision trees in the coming year that a clear vision of the future is not possible.

[Zvu]

About the distortion - there are distortion measurements of C90-6-724 on the web and as was posted earlier in this thread, HiFi-selbstbau did it as well. As was noticed before with ET's midrange, 3rd harmonic is higher than second - unlike measurements from German website. That being said, it's not that ET's mids have higher 3rd harmonic, they rather have lower 2nd harmonic than the one measured on the web. From the one measured by the ET, 3rd order HD peak is at 3.1KHz and it is about 0.6% at its apex (about -44dB).

Slight digression: Recently i've been told about German DIY-er named Rainer Feile that constructed a small two way loudspeaker he named Tafal. While being nothing revolutionary in itself, it gained much popularity among the European DIY-ers because it's made with high value drivers and with a good number of smart design choices. The thing i liked about it (among other things) was that, while he did use Seas alu-dome tweeter that has break up at 26KHz, he treated it with a notch filter.




As expected, there was 3rd HD peak at roughly 8.7KHz that reaches 0.3% line. What surprised me is that when notch is applied at dome resonance, the 3rd harmonic distortion peak decreases dramatically - from 0.3% to 0.04%. What's also interesting is that it lowered 3rd order HD through the entire tweeter range. Measurements before and after:





Now, i know that this should be tested but if it works with the midrange too, then it is understandable that with Akira they could do something similar and achieve good distortion profile regardless of high crossover point - given the diamond cone and break up that is much higher in frequency. Since ET made a notch at midrange resonance, i wouldn't be surprised if 3rd HD would be lower through the whole range covered by it with crossover in place. I'm certainly testing it as soon as i deal with my notebook gremlins, but with nothing but the notch at the cone resonance.

[Evil Twin]

I have confirmed this technique in the past with other drivers, and pending measurement of the currently modified drivers with the system crossover, may further employ it again.

But when this may happen is a very open question...

[Zvu]

I hope everything works out for you.

[5th element]

As we all know, the reason for the peak in the third order distortion product, is because of the cone ringing, in sympathy, with the standard distortion product.

In other words we excite with a 1kHz signal, a third order, at 3kHz, is generated within the non-linear aspects of the driver and then the cones resonant peak at 3kHz amplifies the generated third order product.

At no point have we approached the driver with a 3kHz signal, unless it were to be fed with a signal of gross amounts of non linear distortion to start with, so an electrical solution, ie notch filter, tuned to 3kHz would have no effect at all on the frequency that stimulates the problem, in this case 1kHz.

The only way that a notch like this could help lessen the impact of the distortion amplification mechanism (the cone ringing) would be if the tuned notch were to present a low impedance to the driver at 3kHz and therefore provide resistance to the motion of the ringing of the cone.

[fish fingers]

"The current status of this project is equivalent to being frozen in carbonite"

I hope all will be well soon.
It may have been covered already, but how did you solve the tunnel resonance issue with the C90's?




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[Zvu]

As we all know, the reason for the peak in the third order distortion product, is because of the cone ringing, in sympathy, with the standard distortion product.

In other words we excite with a 1kHz signal, a third order, at 3kHz, is generated within the non-linear aspects of the driver and then the cones resonant peak at 3kHz amplifies the generated third order product.

At no point have we approached the driver with a 3kHz signal, unless it were to be fed with a signal of gross amounts of non linear distortion to start with, so an electrical solution, ie notch filter, tuned to 3kHz would have no effect at all on the frequency that stimulates the problem, in this case 1kHz.

The only way that a notch like this could help lessen the impact of the distortion amplification mechanism (the cone ringing) would be if the tuned notch were to present a low impedance to the driver at 3kHz and therefore provide resistance to the motion of the ringing of the cone.

That's exactly why i said i'm gonna test it with nothing but the notch filter on midwoofer's resonance - taking rest of the crossover out of the equation. Crossover for Tafal is nothing unusual so you can model it in a simulator. Here's the entire project in PDF: http://www.sinus-pollux.de/downloads...feile_Doku.pdf

[Bukem]

Great project!

Can you elaborate on the stuffing/damping of the midrange enclosure? Also, what is the internal length and diameter of the tube?

[JonMarsh]

I've been keeping an eye on this project... it's gone quiet lately.

The midrange tube runs most of the depth of the enclosure, based on some spy pictures I've obtained (yes, I am a rebel spy). My informants say it will be lined with a high density material and loosely stuffed the entire length with Acousta Stuff.

It's reported that since the death of the Empress, a combination of dissension within the Imperial ranks and logistical issues has forced a relocation of the project to a different star cluster just recently. But as many activities remain to be completed here before ET can relocate, completion may be pushed out in the future a couple of years or more.

[Zvu]

I don't know if anyone posted this here but it is good comparison - as if there weren't bunch of measurements for this midrange already

https://www.hifisound.de/out/media/pdf.php?r=DpU%2BIuN7sO9OqmJeE%2FBrLp2J7oOzt9kkytGuNCpShsywkCutT%2FkojJMpHxrAI1WcCDJTbvrodUrZcyeF%2BOaL%2Fg%3D%3D.pdf

[Evil Twin]

status and progress...

At times it feels as though I am the one that has been in carbonite hibernation for the last year plus, but as many have said in the past, life is what happens while one is busy making other plans... plans that must be set aside or deferred for a time.

I acknowledge and appreciate the many comments and contributions, and the PDF download links- they touch on important points that were undergoing investigation, and which have since been restarted, but not yet completed.
‘
Improving the usability and performance of drivers in spite of their breakup modes is an interesting challengeo- there are clear hints in the redacted work published by Rainer Feile which are quite useful to those skilled in the arts- there are some test cases now in evaluation which should prove interesting.

Furthermore, new components, such as the BlieSMa tweeters open up some further possibilities- and events are in motion already to evaluate and follow up on their potential.

Regrettably, by the fastest available travel the existing work and components are a full day’s travel away in storage- but for the purpose of some specific studies, this can be addressed later this year.

Of interest to some may be the subsidiary company created by Tidal-Audio, Vimberg.

They produce a model very similar to the Akira, the Vimberg Tonda, but with basicaly standard Accuton components and more cost sensitive design and construction. However, that is still a relative concept...

https://www.soundstageultra.com/index.php/features-menu/opinion-menu/854-jeff-buys-loudspeakers-the-vimberg-tondas

[Juhazi]

I hear ya. But then again i never listened midrange with a cone that's rigid as that one and when such experienced guy as Atkinson is impressed and starts talking - i choose to listen. Measurements will show us one part but he is genuinely impressed by the sound - if it's not an act of courtesy. I do hope Akira finds its way into Stereophile testing facility aka Johns room.

My real concerns goes into direction where 6000Hz is the upper crossover point. That's why i'd like to see those off axis measurements.

Tidal Akira's test was published in October. Xo points are 250 and 2200Hz. Sadly Stereophile doesn't publish distortion measurements.

Averaged horizontal +/-15¤


Normalized off-axis is super smooth!

[Evil Twin]

It may be wise to consider that from high end manufacturers, published specifications may have more grounding in Marketing and misdirection than in the actual design. It is also possible that the stated operating range for the diamond version of the midrange is 6kHz, based on Accuton's on axis measurements, but we all know full well how "optimistic" those operating range statements from Accuton are- again, a likely product of Marketing departments, not Application Engineers.

The data Juhazi links leaves little doubt about the general engineering capability of the Tidal-Audio team, though. Somewhat surprisingly, the 1kHz bump in response due to the midrange driver mechanical construction has not been completely addressed... it is possible to do better.

[Evil Twin]

More about the Vimberg Tonda

Some new data points came to light today- with the Vimberg Tonda. it is not quite so direct a clone of the Akira as might be thought...

Reviewing some pictures raised questions in my mind...





Steve Manning confirmed my supposition regarding a different midrange driver based on the visual proportions above...

And even though the verbiage below states otherwise, there is no way I do not recognize the C168, having tested several of them...









Never trust a marketing person to do an engineer's job...

[cochinada]

It also mentions "...with a 90mm Accuton ceramic midrange woofer" but in the specs below there is no such thing.

[Evil Twin]

It also mentions "...with a 90mm Accuton ceramic midrange woofer" but in the specs below there is no such thing.

Exactly....

[ergo]

A very strange website they have with lots of contradictory data, the back view on Philosophy page stirs the muddy waters some more ...


Anyhow - a clone build along these lines will be fun to watch for sure. Building this would be out of reach for many of us without the imperial contracts, but fun to see and hear about regardless.

[ergo]

And on Handmade page again like they are showing pics of 2 different models

[fish fingers]

cd be wrong, but think there are 2 sizes in Vimberg range, one using C90, the other C168.

v glad to see this project back on again. tweeters.. the new SS Ellipticor tweet cd be an interesting combo with C90 or C168...silk dome with ceramic mid. or Viawave GRT145 (non waveguide?) with C90 perhaps. or Beyma TPL75, if all black drivers

[Juhazi]

Vimberg Mino has C90 and Tonda C168

https://vimberg.de/loudspeaker/

Viawave GRT-145 has minimal hor. directivity http://www.troelsgravesen.dk/Viawave-GRT-145-4.htm



BlieSMA is however surprisingly good for it's size http://www.troelsgravesen.dk/BlieSMa_T34B-4.htm

[fish fingers]

Troels has used both BLIEsma domes, Viawave and Ellipticor tweet. He liked all of them!