Ardent D (aka Kurosawa Jr) Winter Camp

[dwk]

Are the drivers DA25/RS52AN/AS168 already final choices or still surveying?

That's the lineup for the primary design that is being worked on. I believe a 'budget' version using the Anarchy woofers rather than the AS168 was in the original vision, but I'm not sure of the status of that. The discussion above about Z-alignment makes me wonder whether reworking the xover for a conventional cone woofer might run into some problems - not nearly as tricky as the M/T alignment I'd imagine, but perhaps enough to upset the Duelend alignment.

Interestingly, Madisound doesn't list the AS168. they do list the AS190, but the AS168 seems to only be available through Solen in NA at the moment.

[Evil Twin]

That's the lineup for the primary design that is being worked on. I believe a 'budget' version using the Anarchy woofers rather than the AS168 was in the original vision, but I'm not sure of the status of that. The discussion above about Z-alignment makes me wonder whether reworking the xover for a conventional cone woofer might run into some problems - not nearly as tricky as the M/T alignment I'd imagine, but perhaps enough to upset the Duelend alignment.

Interestingly, Madisound doesn't list the AS168. they do list the AS190, but the AS168 seems to only be available through Solen in NA at the moment.

You have the correct sense of it... this is a Design Study, but the cabinets have been built for these specific drivers for this design study...


In order to move the result of the design study to something closer to Steve Manning's needs, another major pass of the crossover design has been completed. The primary goal is like the TV manufacturers of old in this system- how many parts can you take out and still adjust the design to hit the target functionality, perhaps with some compromise in factors such as variation of impedance curve? Of course, the target is size and cost reduction. This has been accomplished successfully, with the "bonus" of better compliance to the "standardized" voicing target curve. The parts for the woofer section have arrived, and that section is floor planned in Altium Designer, and could be transferred to a producible PCB design if there is interest or need down the road. The midrange and tweeter components should arrive on Monday.

Additionally, a variation for the center channel three way design has been modeled after taking data with the Anarchy 558, and a very satisfactory POC curve produced while still accounting for the driver Z axis offset. interestingly, these are actually 9 ohm drivers, like the AS168. But crossover parameters have to be adjusted, as they do not exhibit the "built in BSC" compensation of the AS series parts. Also, this is without diffraction control measures on the front panel.







To illustrate the difference in behavior of the cell drivers, here is an outdoor measurement of the AS190 on an optimally sized baffle - about 12" wide.



As you can see with this driver, and also with the AS168 and AS250, there is no apparent baffle step, because as a part of the driver design, that is engineered into the characteristic. The Force is strong with this series...


Incidentally, I have also obtained AS168 from Intertechnik in Germany, as well as Solen.




I now have BlieSMa T25A-6 tweeters on order with Solen, though, as reducing the CTC distance is desirable, especially for the CC design application which Steve needs. Other candidates have fallen by the wayside due to either performance issues or price considerations.

A test cabinet is in preparation for evaluation for the CC application using the Anarchy 558. PuriFi drivers are on hand but challenges with the number of upcoming runs to the Outer Rim for relocation of the laboratory may necessitate putting off that investigation. Materials for test cabinets are on hand, but there are only so many weekends between now and the end of December.

[kevinlin1013]

Thanks for your reply.
Are you meaning there will be two versions of Ardent D?

As an accuton fan,I am really looking forward to AS168 version.
I am just only a little worried about if AS168 could go that high to meet RS52AN around 700~800Hz due to a little heavy Mms.

[Evil Twin]

Some points to keep in mind...

This is a design study, and using the Duelund approach, the effort will tend to be design centric around the midrange driver and matching the other driver's net transfer function to it.

Additionally, the Ardent D is basically just a POC exercise, as their are other targets for this work being done for Steve Manning- a tower design, and an updated center channel design.


To recap again, the planned system design target upon which work to date has been based:






For a practical Duelund type design, it has been my experience that managing the response profile accurately down to the -18 to -20 db level is both necessary, and for the most part, sufficient.



The ultimate targets are a tower based on this cabinet design, and a center channel. They do not (at this time) use the same woofers, though they may both wind up with the same tweeter (T25A-6)






Note that the final tweeter choice is based on both performance targets and minimizing CTC distance with the midrange. For this reason, the DA25 is not an optimal choice, but was deemed acceptable for the first POC design and build.


For the first pass on the tower configuration, it was preferred to use a woofer that behaves as if acoustic origin in in the mounting plane. There are few choices, and the AS168 is the best candidate at this time.

Distance measurements in room with long gating in a small test box show the expected response- as well as the superior off axis behavior of a "dome" woofer...





This design will follow past practice as started in the NatalieP project from 2005, using an elliptic high frequency filter to suppress the driver breakup resonance and reduce or eliminate the distortion resonance amplification usually caused by this breakup mode. This concept was applied to the tweeter section with the DA25 as used for the Calliope for Steve Manning, with the expected results... in this case, like the NatalieP, it is also applied to the woofer.






Last year it was brought to my attention that a German DIY enthusiast had published a Compact Monitor design with Seas aluminum tweeter and Visaton woofer using the same concepts for HF breakup resonance control, though with a more conventional series parallel RLC filter configuration. The current filter design for the AS168 meets those targets.

Another woofer that will be investigated for the tower that is on hand is the PuriFi 6.5". The time offset is a concern, but it may still be usable. However, for a preferred configuration we will need to source the 8 ohm version- for the higher system sensitivity. The 4 ohm version could be used like the configuration of the Wavecor Ardent, which makes for an easy to drive system load, but for many the higher system sensitivity with solid state amplifiers may be preferred.


For a CC application, two relatively shallow woofers are being evaluated- the Anarchy 558 and the Esoteric ES140.


Measurements and an initial POC design pass show that the Anarchy should be usable. It also has an elliptic filter to reduce HF breakup behavior to a very low level.





The Esoteric should be even easier to implement, but the drivers are more expensive. The Anarchy 558 uses an XBL2 motor system and is quite tolerant of being driving to higher output levels.

The CC is not being designed as a full range system, of course, but as an 80Hz and up speaker.

Crossover configurations are being developed with a modular approach and to support the use of PCB construction in the future, if desired. Initial layouts are complete for application variations of the filter configurations for each crossover stage (Low frequency, midrange, and high frequency).


This should lay out the overall goals and development paths of this design study. Not all of them may be realized to complete satisfaction- that is why the effort, including alternative configurations, must be undertaken.

However, I do have some confidence that all of the proposed configurations will prove to be interesting... most interesting.

[dwk]

Just to be clear, it seems that a floor stander with with Anarchy 708 in place of the AS168 is not a configuration that is being looked at in the initial set of tests, then?

[Evil Twin]

Actually, the 708's are... as regards POC exercises based on driver tests in a woofer only cabinet for now, of the proper dimensions- but due to the pending relocation of the design laboratory to the Outer Rim, completing and testing a finished design will spill over into 2021.

Note that I have already posted the POC design for the 558's. (this is for potential CC configurations). It seems that the time delay offset will be manageable, as it was for the original NeoD CC. Note that I also received more Esoteric EDS140ti this week, and as my initial Force intuition suggested, the dimensions given in the Dayton data sheet are not quite right, but the parts themselves are- they are a perfect match up to the 558 for outer rebate diameter and the inner through hole, and so an already prepared test cabinet will be readied shortly for testing the ES140ti.

The 708 drivers are here, the text enclosure pieces are ready to be assembled. My personal preference might be to move them up in the hierarchy, but this development is being done for Steve, and so he has some say in priorities...

Also, in other "good news" is shipping notification for the set of BlieSMa T25A-6 to evaluate.

[Evil Twin]

Finally, to demonstrate that a modicum of productivity has resumed, an example of the 2nd generation Woofer crossover boards.

As I described to Steve Manning, this is the Premium component "Mad Muntz" version... (take out parts until it stops working...)





As you can readily see, "Black is back" is more than just a catchy slogan...

[Bear]

Interesting to see the small p-Core. Was that because of the DCR requirement, form factor or it was just on-hand?

[Evil Twin]

Interesting to see the small p-Core. Was that because of the DCR requirement, form factor or it was just on-hand?

We had acquired a number of PCORE parts to test and evaluate- for this design study, due to the AS168 characteristics, a large inductance is not required, as a characteristic akin to baffle step compensation is engineered into the drivers.

Both inductors are the same part, but one is unwound to the specific needed value- DCR, as you surmise, is quite low with AWG13 wire- this was an experimental design target. The PCORE material is more linear than the CCORE Jantzen, and doesn't exhibit low level variations in hysteresis that show up as inductance variation and distortion. So far, I am favorably impressed with the PCORE parts, but more testing remains to be done.

[Evil Twin]

Test Article 2 DA25 Tweeter crossover

construction continues

[kevinlin1013]

Crossover looks good overall!

The "bump" near 2.1 kHz is a little worrying though. (..this is about the area where I typically experience a trace of "hardness" subjectively with this sort of result.)

The phase angle near 50 Hz isn't kind, but the Impedance isn't low at this point so it shouldn't be difficult on the amplifier.

It seems that the bump is from resonance of RS52AN.
My RS52AN also has this issue with discontinued point at the impedance curve.

[Evil Twin]

Initial testing of 5 samples of Morel EM1308 have proven encouraging, as reported elsewhere...




A new crossover update has been prepared, and is ready for testing on Saturday...




If the results correlate well with the newest system design simulation in VituixCAD, then assembly of the Test Article 1 will be undertaken.

[Bear]

A new crossover update has been prepared, and is ready for testing on Saturday...

There are some big values in there, but the overall part count is ... not bad for a mid, let alone a Duelund.

[Evil Twin]

The two large capacitors are in "auxiliary functions". The largest is used in an RLC equalizer to flatten the small bump in the dome mid response between about 1250 and 1500Hz (this is the "perfectionist version of the crossover), and the next largest cap is part of the RLC impedance zobel for the Fs resonant rise of the EM1308.

[Evil Twin]

there is progress, but many other high priority tasks to attend to... there are many disturbances in the Force, and several cargo runs to the outer rim in advanced planning stages...

But perhaps this image will be interesting... as the first test article is now assembled.






And a view without the dolly...

[1Michael]

Shiny!

[Evil Twin]

Some small progress at last...

It is appalling that so many weeks have gone by without posted progress...

But the Bantha's share of effort has been devoted to developing new training materials for members of the New Empire, and locating and securing a temporary base of operations in the Outer Rim- all now completed successfully... which permits some time for other activities, though the regular logistic runs to the Outer Rim in my personal shuttle will continue.

I can now say confidently, for the moment, that events are proceeding as I have foreseen...


Turning to the acoustical issues, the cabinet and driver assembly tasks for the first test article were finally completed last week- no more delays will be permitted. Captain Needa shall fail me no longer...





I had delegated the initial LF testing to him, in the non test article cabinets, but it seems he made some errors in calibrating the sensitivity measurements and calculations, and so the matching of the woofers and midrange/tweeter were not as planned, but out of synchronization by about 2dB.

Drawing on the powers of the Force, I evaluated many possibilities, and arrived at a solution correlated with the current measurements that shows with the addition of one resistor to the midrange crossover, this should be the final results...




Should this not be the case, I will be at an impasse, as I have run out of lackies to terminate at will... however, I have taken exacting care with the calculations and simulations, and believe I can place a high level of confidence on this result.

However, voicing compensation then be required with an inline filter between preamp and power amplifier, as previously proposed by Jonmarsh elsewhere on the forum.

[bobulator]

My Lord,

Where did you obtain the beautiful feet used on this system?

[Scottg]

At the risk of a force-choke.. :P

This looks a bit "forward" to me (..say 1.2 to 2.7 elevation from the average):

[ATTACH=CONFIG]30805[/ATTACH]

..whereas this looks better (..though I personally wouldn't have a problem with the treble being *elevated a little from this a'la Spica):

[ATTACH=CONFIG]30531[/ATTACH]

*to help with some of the pressure loss off-axis at higher freq.s. and the in-room result.


-of course there is modeling an then there are real-world results..

[Steve Manning]

I'll leave to the Master to answer questions on the voicing, but since I was lucky enough to provide him with the location of these feet, here ya go. https://www.amazon.com/dp/B07SNSMW7D/?coliid=I53MFNVRNENJY&colid=1VRILJ6X65H23&psc=1&re f_=lv_ov_lig_dp_it



Look around a little since I've seen several companies offer them and the prices vary considerably.

[bobulator]

Thanks, looks similar indeed, and reasonable price for sure. Funny that there are several listings for what appears to be the exact feet at different prices. Not sure what the tiny rubber foot will do, seems it would deform pretty easily for a heavy speaker. And if you use the other side, the small cone, wouldn't get thru much carpet.

[bobulator]

I'll leave to the Master to answer questions on the voicing, but since I was lucky enough to provide him with the location of these feet, here ya go. https://www.amazon.com/dp/B07SNSMW7D...v_ov_lig_dp_it

Look around a little since I've seen several companies offer them and the prices vary considerably.

Funny, like 3x the cost on Amazon vs. ebay! All the pix are the same, so I assume they are the same, but you never know with Chinese sellers.

[bobulator]

Oops, nevermind, that was for a single leg! But they are cheaper on fleabay, here's a set of 8 for $88:

https://www.ebay.com/itm/8x-High-Quality-Aluminium-Speaker-Spike-Pad-Floor-Stand-Spike-Feet-Nail/173881689877?_trkparms=aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D229879%26meid%3D1245909e1a22445c9d9e71209390bf9d%26pid%3D100005%26rk%3D4%26rkt%3D12%26mehot%3Dco%26sd%3D173877966801%26itm%3D173881689877%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3DSimplAMLv5PairwiseWebWithDarwoV3BBEV2b%26brand%3DUnbranded&_trksid=p2047675.c100005.m1851

[Evil Twin]

At the risk of a force-choke.. :P

This looks a bit "forward" to me (..say 1.2 to 2.7 elevation from the average):



..whereas this looks better (..though I personally wouldn't have a problem with the treble being *elevated a little from this a'la Spica):



*to help with some of the pressure loss off-axis at higher freq.s. and the in-room result.


-of course there is modeling an then there are real-world results..

Very reasonable comments- keep in mind that this curve is simulated, based on adjusting data, and small additional changes can be easily made.

I am torn between the concept of building in the voicing compensation curve, and simply designing the speaker as flat as possible with a wide dispersion profile, and doing the voicing inline as has been shown in the thread on that topic, with a balanced XLR device in the signal path between preamp and power amp.

Forward progress is at a glacial pace due to the press of current Imperial activities (training Sith apprentices... I don't know where they find these candidates, it's not like the old days...), and support for the Outer Rim relocation- the Imperial activities will be complete on December 18...

However, the progress to date is encouraging that the final result may be satisfactory...

Even today I spent a small amount of time setting up for building the second midrange crossover and making the required minor modification to the first...

[Evil Twin]

Second test article...

The last two weekends I have been able to spend some time NOT traveling between the outer rim and civilization as we previously knew it...

After some meditation months ago, I decided upon a course of action including the planned updates for the second test crossover and cabinet. This actually only involved finishing the crossover builds and modifying a few resistors, changing the series resistance and adjusting the loaded resistor, in fact, using that to tune the bandwidth curves for the midrange slightly.

On the other hand, I am continuing with some built in voicing, pray I do not make further changes to the bargain. An experimenter skilled in the arts can always update to their preference, should they choose to walk down this path...

This post is just to inform of some of the results for the second speaker, both measured and after some listening in mono using the measurement system, which currently incorporates a Moto M4 interface, a Benchmark HPA4 preamplifier, a Cambridge Audio 840W power amplifier, and a MacBook Pro for the test source, using VOX for music playback samples.

The location of the test speaker is in the dining/living room of the new home, about 5 ft from the back wall.




Impedance measurements agree very closely with both Unibox and VituixCAD simulations, confirming expectations that the crossovers were built correctly. They also confirm the correct low frequency tuning, with maximum PR loading at about 28Hz, and show the efficacy of variable density damping at preventing any column resonances that might be observed in the impedance curves, as was the case for the very first generation Ardent in a ported configuration.




A number of measurements were made, with minimal smoothing but using Half Hamming windowing and a 150msec window, which reduces the measured low frequency response. However, with a rectangular window it can be seen that apart from the room modes, the response reaches about 30Hz at the -3dB point. The result was adequately in synchronization with the design target. The dips in the 40-50Hz region and 130 Hz are due to room modes, and native response was verified with close miking. The midrange and high frequencies were very clear on the test sweeps, but not drawing attention to themselves in any particular area. The polar response changes little up to 45-50 degrees off axis until above 10kHz due to the behavior of both the dome midrange and the DA25 tweeter



A variety of program material was auditioned using the stored FLAC files and the VOX player- this included a high definition SACD rip of Gaia, by James Taylor, "What I am" by Edie Brickell, "East River Blue" by Spyro Gyra, "Ectopia" by Oregon, "Rich Woman" by Allison Kraus and Robert Plant, "The Lighthouse Tale" by Nickel Creek from an SACD HD rip, "Gaucho" from an HD SACD rip, "No one is to blame" by Howard Jones, the live version of "Chrale No. 1 "Sleeper" by the Jacque Loussier Trio, "Against the Wind" by Marie Brennan, "Dark Alan" by Karen Matheson from Rob Roy, several Poor Claires cuts, "Chant" by Fourplay, "Corner Pocket" by Harry James & His Big Band, and "Spiral" by Hiromi. Of course, this was just one channel.


The most interesting impression was how neutral sounding the experience was, but particularly how the pitch definition in the low frequency instruments (such as standup bass, bass guitar) did not seem to have a specific warmth or range emphasis, but rather was very revealing of pitch definition and clarity up and down the scale. This was very evident even in pop pieces like Gaia, where the percussion break at the final verse break was reproduced very evenly but with increasing power as the pitch of the drums struck were lower and lower. No bloat, but high impact. At the listening distance of 10 ft, there were more midrange and HF room reflections, but the low midrange and mid bass measured flatter, so I would not consider changing things until a number of additional listening tests and measurements have been made. At this point, I tend to trust the power response profile of the VituixCAD simulations, and what I am hearing subjectively resembles that closely at the listening position.

Live pieces like the Jacque Loussier Chorale were particularly satisfying to me.

Overall, the results justify returning to the TA1 cabinet (Test Article 1) and updating the resistor configurations in the midrange and tweeter crossovers- as well as replacing a midrange driver damaged in warp turbulence during one of the shuttle runs. That is underway since this morning...

Following this, a different system setup will be used for further auditions, with much of the same program material.



The latest Cambridge XD class amplifier, the Edge W, will be used to drive the Ardents. This is essentially the grandson of the 840W amplifier which has been used for years in the measurement test system. It is expected that these listening evaluations can be completed tomorrow.

[kevinlin1013]

Thanks for the updating.
I am very taking note of this project.

[ergo]

Very cool to see this new evolution of Ardent moving along. The measurement plot do promise something great again.

[Evil Twin]

The original TA-1 crossover boards have been modified and will be installed after a meal break.

The interesting thing about this may not be the Duelund crossover, though I believe it has considerable merit, but the electroacoustic properties of the AS168 in combination with the RSS265PR. Accuton made a huge investment in the development of this newer generation of drivers- the original Kurosawa system is awaiting time to complete it's developmental construction, and this whets my appetite for that effort even more... it will be interesting to contrast the performance of the AS190 and AS168. It is easy to imagine from this how the Vimberg Mino creates it's appeal, yet I also think that the combination of the RSS265PR's with the AS168 is a most serendipitous arrangement for a smaller system.

Do note that the measured balance shifts at the listening position, but the changes fully justify what is observed at 1 meter.

[Evil Twin]

Finally ready for listening evaluations

There must have been a disturbance in the Force, because additional updates to the first crossover board were overlooked, and had to be implemented. But now matters are proceeding according to the plan...

[JonMarsh]

Time for some help?

Though Evil Twin really likes to stay in control of matters, sometimes certain issues become obvious... he's lived a rough life, and, let's just say too many 1.21 gigawatt laser blasts going off near you, and that whole Force fire thing, and something's gotta give, especially the hearing acuity...

So, in his rather unhumble and demanding way, he's asked for a little assistance spotting strengths and weaknesses and describing them...





So, I'm starting to put together a variety of impressions based on quite a few disks and cuts I'm familiar with.

One thing that must be said up front here is that this is in a certain sense not reviewing just the design, but is perhaps even more so reviewing the performance of all the component parts of the playback system... that means the drivers in the speakers, the crossover components, the cables, the DAC and Preamp, and the power amplifier. Change out any one part, and it won't be quite the same...

Second, there seems to be a moderate amount of synergy going on here... maybe more than a moderate amount. We'd always like to say it was PLANNED that way, but luck does sometimes happen... take advantage of it, but don't take credit for it?

All the cuts I've played are clearly the same cuts as I've played before... but in many cases the presentation has been elevated to a different, unexpected level. In others, maybe the demands aren't as high, the mastering not as innovative, but things are still clearly working pretty well.

This will take a few posts because there is a lot of material I'm going through, and I'm just scratching the surface- many CD's are packed away in storage. But so far its pretty interesting...

[technodanvan]

I'm looking forward to seeing which tracks you play, I've purchased several CDs that you and others of this forum have shared over the years.

[theSven]

Looking forward to seeing what results you share. I wonder if I’m gonna need to save up and get a terminator or how it would perform with the Emotive XMC-2.

[CADman_ks]

Glad to hear that your having good luck with the crossover voicing.

...

..."The Lighthouse Tale" by Nickel Creek from an SACD HD rip

...

I've seen Nickel Creek live in person numerous times, but when they were kids just starting out. They used to play at a local festival.

The Lighthouse Tail is one of my favorite songs of theirs, but I like them all. They are definitely talented musicians for sure...

[Scottg]

So, I'm starting to put together a variety of impressions based on quite a few disks and cuts I'm familiar with.

I use this one for testing image placement and in particular - stability with multiple sources (..because of the way instruments are added into the song):

This is a good one for synthetic "space", as well as texture and detail:

..and some others I like for varying reasons (to gauge system and particularly loudspeaker performance), though all have "space":

This next one is actually a longer than presented:

[JonMarsh]

I’m out on the road, but will check those out when I get back- thanks Scott! I’ll have to get the Mutec interface working to use those, I think.

I have a huge list of CD’s and tracks, too- I have to figure out how to cut it down a bit- and I’m also going to try connecting one my MacBooks to the DAC via the Mutec MC3+, which has a special USB input. Maybe do a comp with something I have the disk handy for, too.

[JonMarsh]

Glad to hear that your having good luck with the crossover voicing.



I've seen Nickel Creek live in person numerous times, but when they were kids just starting out. They used to play at a local festival.

The Lighthouse Tail is one of my favorite songs of theirs, but I like them all. They are definitely talented musicians for sure...

I became aware of them because Sony released an SACD early on of their self titled album. Oddly, I’d always liked it, but it’s just the last few years I’ve gotten into a lot of their other stuff. For a band with their roots in bluegrass, they’ve grown in some interesting ways!

For me, “Why should the Fire Die?” Is probably my favorite- partly because I like to sing along with it on the long road trips by myself, and partly because it stretches their boundaries so much thematically and musically. From the incisively biting lyrics of “Somebody more like you” to the dynamics and melodic variety of “Helena” which ends in a verse that would justify a guest appearance on drums from the beyond by Keith Moon.

[JonMarsh]

WIP update

OK, just a bit of a WIP (Work In Progress) update, partly feeling guilty because though I was initially considering posting a list of cuts and detailing my perceptions of each one, I realized THAT would be rather a time sink to generate AT THIS POINT in comparison to the relative worth- so for now that will be deferred.

Also, I've had some extra work to do, because the two cabinets, named TA1 and TA2 (Test Article 1 & 2) have had some differences in execution which now need to be normalized, TA2 naturally enough being the later version. And I've found that attention to some relatively small details is required to achieve intended results...

• The stuffing technique for the upper cabinet region in TA2 was chosen using a higher density approach, with the fiberglass typically used for wrapping pipes, instead of Acoustastuff. By testing, this is now chosen to be the preferred configuration.
• The padding for the midrange and tweeter are going to be altered once more, raising their levels slightly.
• The phase centers for the 180 degree transition are being better aligned (I think!) by some crossover updates as well as build updates.
• For the tweeter crossover, the cacluated value of C7 is 2.4uF, while I was using a standard 2.2uF Jantzen. Not goodly- need to add in 0.22 uF to bring it to target value.
• C12 is also being updated, mainly for aligning the phase, as it has impact on roll off only below -12 dB.
• The pole stop resistor R12 in the woofer network is being changed from 5.1 ohms to 10 ohms. Again, primariliiy for adjusting the phase response.

As previously built, the speakers are very pleasant to listen to, and the AS168 + RSS265PR combination shines in the very, very stiff cabinet. The LF pitch definition, articulation, and extension are all very pleasing, on cuts ranging from Stanley Clarke's "School Days" (from the Bass-ic collection, the named album of the same title is a very poor CD master) and Wild Dog, to "Gaia" (James Taylor SACD) to Lorde's "Royals". The percussion roll through in the opening of "Wild Dogs' is a particular example of all of those characteristics.

But I feel like there is a little more focus overall to be obtained, and that's what's driving the updates. Parts ordered, with expedited shipping.

I think Accuton has definitely scored an important technology development with the AS series cell woofers. They have some rather unusual characteristics, and have been clearly engineered for a fairly specific application approach. This 1 meter plot in a small sealed test enclosure for the AS190 exhibits the key characteristic I've seen in all the cell woofers...



This is not an infinite baffle measurement, but a 12" wide test enclosure... yet there is no baffle step fall off, because there is a counter vailing property built in to the driver, perhaps as a consequence of the effort to create an acoustic origin at the mounting plane?

But this has significant implications with the crossover design for a conventional cabinet, as a large value inductor to create the BSC pole around 250-300Hz isn't needed, and the crossover network looks more like a classic filter, due to the flat impedance curve and lack of BSC compensation. This can cut the initial inductor value in half, and reduce DCR. For this crossover implementation, DCR was minimized by using Jantzen parts with AWG13 wire, and creating a custom 600uH inductor by unwinding a 1mH AWG13 part. (That was done because the 0.68mH part was out of stock at the time!) (this was the cost effective approach- the rabid approach would be to take the 3.6 mH parts and unwind them, which use the larger core, but cost more. Lower net DCR. )

It also reduces the interaction of the LF filter with the overall driver impedance variations, which can be often be seen in the upper bass in the actual filter plot in the design program, typically with a bump of a few dB in the 100Hz region. This is eliminated with the cell woofers, and this characteristics is common to the AS168, the AS190, and the AS250, based on my direct experience.

[kevinlin1013]

Jon thanks for the update post. The ”built-in baffle step compensation" is really impressive.
It also make the ”spec sensitivity” of the woofer more close to the finished loudspeaker.
As a fan of Accuton I am always thinking that they are always making the innovation of the dynamic speaker driver. Both the diaphragm and the structure.

When I was searching information of the AS190 , I found that there are two model numbers of it
One is AS190-9-251 and the other is AS190-9-252. From their datasheet curve , one has the ”built-in baffle step compensation" but the other is not.
I am confused that if it is just a a mistake or there are two models of AS190 actually.

[JonMarsh]

Several years ago there were two versions of the AS190, but they differed just in the voice coil resistance rating- the higher ohmic version intended for paralleling, either 2 or 3, such as in the Tidal speakers, or the design in progress that I have (which is sort of a Tidal Klone but with the ceramic parts and a different tweeter- no diamond midrange. On the web site today, there is only the 251 version listed on the Auccuton site.

I’ve never seen anything but the one version of the AS168. OTOH, Accuton has introduced a new version of the C168 intended as a midwoofers, and it has more conventional response (I have a pair of the C168-6-89-0 now) and a new motor and suspension implementation. But it while it has the acoustic origin in the mounting plane, this is due to the voice coil being very large and attaching to the edge of the 6” ceramic cone. A big claim to fame for this driver is very low distortion with a conventional mid woofer Xmax (unlike the earlier C168-6-990 which is just a midrange). Early charts on Madisound seem to confirm this, but they haven’t posted that info on Accuton.de yet, not even as of today.

[kevinlin1013]

Jon , thanks for your detailed explanation.
I saw that 2 type AS190 at the German audio shop called hifisound.de

https://www.hifisound.de/de/Lautsprecher-Selbstbau/Accuton-AS190-9-251-Cell-Concept-Driver-Keramik-Bass.html

https://www.hifisound.de/Do-it-yourself-Products/Speaker-Drivers/Accuton-AS190-9-252-Cell-Concept-Driver-Keramik-Bass.html

I am also very interested in C168-6-890 which is the mid-bass version of C168.
The german magazine Klang + Ton has a project called Accutop done by this driver with a audaphon ribbon tweeter(Aurum Cantus rebrand , obviously)

https://www.lautsprechershop.de/hifi/accutop_en.htm

It is interesting that Accuton is posting C168-6-990 at their english site:

https://accuton.com/en-home/produkte/lautsprecher/keramik/Keramik-C168-6-890-CELL

Another interesting thing I found is that the Lumenwhite Kyara seems using a different look AS168 , maybe a NEO magnetic?

[JonMarsh]

Yeah, the OEM’s have a much bigger bag of toys to access from Accuton than we do!

I still think it’s also a bit weird how Accuton has been a bit coy about rolling out specs- complete plots on the Madisound site for the 890, and on Accuton’s site, it’s just “coming soon”.

[kevinlin1013]

Jon , thanks for the reply.
BTW , I pretty appreciate the design of Lumenwhite from 2003 I met them. Their cabinets are more like an "curved open baffle" than an traditional enclosure.
Their speakers also made me become a fan of Accuton drivers. It is sad that the original designer already passed away.
Since it seems that Avalon/Marten/Tidal/etc..are selling more speakers than Lumenwhite nowadays , those brands may also use the custom drivers.

Also , for your reference , one of the dears of Accuton drivers called aedio in Tokyo/Japan where I live at now has posted the datasheet of 890 on their website.

https://aedio.co.jp/catalog/DS-C168-06-890.pdf

[Scottg]

..just “coming soon”.

Isn't this what we've been getting from the ISP industry for the past 20 years for fiber internet everywhere in the US? :roll: (..despite the Fed. government paying/granting ISP's 10's of billions of dollars every few years.) 8O

[technodanvan]

Accuton probably has a better record than government projects, much less contractor-driven projects.

...speaking as a contractor.

[JonMarsh]

Isn't this what we've been getting from the ISP industry for the past 20 years for fiber internet everywhere in the US? :roll: (..despite the Fed. government paying/granting ISP's 10's of billions of dollars every few years.) 8O

Now that definitely hits a raw nerve with me, as well as with others, I'm sure! In some markets AT&T has launched an advertising blitz for fiber, and where I'm living now, less than a mile away homes built in 2018 have fiber, but this ten year old home I'm renting has best case internet connection that should probably be referred to as "juiced up DSL", with 1/4 the download bandwidth I'm used to working with.