For the record, the Ferrite JA-6681 also had an AlNiCo sibling: the JA-6670:
YAMAHA ƒz�[ƒ“ƒhƒ‰ƒCƒo�[ƒ†ƒjƒbƒgJA-6670‚ÌŽd—l ƒ„ƒ}ƒn
(even more unobtanium, I think...)
Cheers,
Marco
JA-6670 or JA-6681B + Azurahorn AH425 for my source material?
How do the JA-6670 and JA-6681 sonic signature compare? Apart from the JA-6670's Alnico magnet, are they otherwise identical (i.e. same FR, sensitivity, aperture)? Availability?
Would both sound good in Azurahorns-specifically the AH425?
Azurahorn -Le Cleac'h Acoustic Horns - Products
What especially concerns me is how my less than ideal source material would sound though either of these drivers. Which of these drivers may be the more forgiving of recordings that are somewhat to considerably harsh or distorted or “congested” during orchestral passages?
Note that I'm not concerned with the drivers' HF response, since I'd be adding a RAAL Lazy ribbon tweeter, and that will be switched in for my high quality recordings. Nor do I need the driver to reach low as I’d be crossing my sealed GPA Altec 416 midwoofers to play from 700Hz to 70Hz.
Of course, the problem with these drivers is parts and repairs. Is there still no one in the world who can perfectly clone and install JA-6681 & JA-6670 diaphragms and suspensions?
As I seek the best informed opinions on choosing between theses drivers for use in an Azurahorn 425, please feel free to pm me for access to my Outlook cloud to evaluate my recordings. You may not like my music, but for those WAV files that will likely sound distorted to you (i.e. Bernie’s Track 11, Frontiere Track 1 of 4, “Hey Gyp”/ Animals), please try to decide between the JA-6670 or JA-6681B + Azurahorn AH425 as the more forgiving-unless it would compromise the sound of my good recordings, below where the RAAL ribbon tweeter would take over. Thank you.
How do the JA-6670 and JA-6681 sonic signature compare? Apart from the JA-6670's Alnico magnet, are they otherwise identical (i.e. same FR, sensitivity, aperture)? Availability?
Would both sound good in Azurahorns-specifically the AH425?
Azurahorn -Le Cleac'h Acoustic Horns - Products
What especially concerns me is how my less than ideal source material would sound though either of these drivers. Which of these drivers may be the more forgiving of recordings that are somewhat to considerably harsh or distorted or “congested” during orchestral passages?
Note that I'm not concerned with the drivers' HF response, since I'd be adding a RAAL Lazy ribbon tweeter, and that will be switched in for my high quality recordings. Nor do I need the driver to reach low as I’d be crossing my sealed GPA Altec 416 midwoofers to play from 700Hz to 70Hz.
Of course, the problem with these drivers is parts and repairs. Is there still no one in the world who can perfectly clone and install JA-6681 & JA-6670 diaphragms and suspensions?
As I seek the best informed opinions on choosing between theses drivers for use in an Azurahorn 425, please feel free to pm me for access to my Outlook cloud to evaluate my recordings. You may not like my music, but for those WAV files that will likely sound distorted to you (i.e. Bernie’s Track 11, Frontiere Track 1 of 4, “Hey Gyp”/ Animals), please try to decide between the JA-6670 or JA-6681B + Azurahorn AH425 as the more forgiving-unless it would compromise the sound of my good recordings, below where the RAAL ribbon tweeter would take over. Thank you.
Let us know what you think of the RAAL with a compression driver. My impression is that ribbon drivers don't mix so well unless you use them as super tweeters.
If you cross at 700Hz, a TAD 4001 would probably sound better in the upper midrange. I think the JA6681B is a bit harsh above 3kHz, bit that could be because of the size of the horn that I am using.
If you cross at 700Hz, a TAD 4001 would probably sound better in the upper midrange. I think the JA6681B is a bit harsh above 3kHz, bit that could be because of the size of the horn that I am using.
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Hi Oltos,
I think you are asking the impossible. The better a compression driver is, the
more it reveals what is on the recording. This is true for "bad" recordings as well.
The experience of a good horn system with good recordings is so fascinating
that I would never build my horn system to sound best on less good recordings.
Btw, congested orchestra sound will always sound less congested
with a system that reveals the minute details better, so I think you should
experiment more with the associated electronics than with the speakers to
achieve what you are looking for.
After my associated electronics reached a certain quality my more revealing
speakers always sound better even on not so good recordings.
The Yamaha JA-6670 has a different geometry than the JA-6681b but they use
the same diaphragm. I spoke with someone who owned both and said the
6670 is better, so if you have the chance to use it do so. Here are two cross
sectional pictures.
Klaus
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Thanks Rewind and Klaus for the very upsetting news. But at least I know the truth
I keep on getting conflicting reports on the JA6681B; some say its flat to at least 10kHz, you say its “harsh above 3kHz”, another found it “gray and coarse sounding”, still another who used it continually for over 2 years says it gave hours of fatigue free listening in his Azurahorn 425 horns.
Those are the horns I’d go with above the sealed GPA Altec 416 alnico midwoofers that I, perhaps rather foolishly, went ahead and built. I’ve been warned that the Altec 416’s dispersion pattern warrants a horn driver above it. Ideally, it would be one that won’t make my poor recordings sound unbearable, while not dumbing down the sound quality of my great ones.
One thing that does seem to be true is that the RAAL Lazy ribbon, when properly crossed, works very well with the Radian Research 745 Neo Be/Azurahorn 425 horn combo above Gary Dahl’s 3 cu ft sealed GPA Altec 416 alnico midwoofers above his 15” AE subs http://www.diyaudio.com/forums/multi-way/100392-beyond-ariel-1356.html Btw, Gary later did further filter tweaks between the Lazys and his horns and got it to perfection, he said.
I thought of the TAD 4001. Do they have a 1.4” aperture to work with the AH425 horn?
In any case, I learned much too late that choice of source material can be a deal breaker. From what Klaus says about better compression drivers, like Gary’s Radian drivers, the 4001s will probably be even more unforgiving of less than perfect source material-far more so than many cone midranges. So I guess it’s a waste of time asking any 4001 owners to run listening test on my WAV files. Boy, am I screwed.
Otherwise, my only alternative looks like the JA6681B-or better the JA6670, as Klaus advised, not that I could find a pair of the latter anytime soon. And of course, replacement parts are not available for either of them.
And what about parts and service for the expensive TAD 4001?
As for amplifiers, Gary Dahl uses Lynn Olson’s Amity 300B mono blocks that he built. I have Nelson Pass’s First Watt J2 and F4 ss amps. Though I’d be using a tube line stage to drive the F4 (a follower amp), most horn people say that even the best ss amps don’t sound nice with their speakers. I guess they should know.
I keep on getting conflicting reports on the JA6681B; some say its flat to at least 10kHz, you say its “harsh above 3kHz”, another found it “gray and coarse sounding”, still another who used it continually for over 2 years says it gave hours of fatigue free listening in his Azurahorn 425 horns.
Those are the horns I’d go with above the sealed GPA Altec 416 alnico midwoofers that I, perhaps rather foolishly, went ahead and built. I’ve been warned that the Altec 416’s dispersion pattern warrants a horn driver above it. Ideally, it would be one that won’t make my poor recordings sound unbearable, while not dumbing down the sound quality of my great ones.
One thing that does seem to be true is that the RAAL Lazy ribbon, when properly crossed, works very well with the Radian Research 745 Neo Be/Azurahorn 425 horn combo above Gary Dahl’s 3 cu ft sealed GPA Altec 416 alnico midwoofers above his 15” AE subs http://www.diyaudio.com/forums/multi-way/100392-beyond-ariel-1356.html Btw, Gary later did further filter tweaks between the Lazys and his horns and got it to perfection, he said.
I thought of the TAD 4001. Do they have a 1.4” aperture to work with the AH425 horn?
In any case, I learned much too late that choice of source material can be a deal breaker. From what Klaus says about better compression drivers, like Gary’s Radian drivers, the 4001s will probably be even more unforgiving of less than perfect source material-far more so than many cone midranges. So I guess it’s a waste of time asking any 4001 owners to run listening test on my WAV files. Boy, am I screwed.
Otherwise, my only alternative looks like the JA6681B-or better the JA6670, as Klaus advised, not that I could find a pair of the latter anytime soon. And of course, replacement parts are not available for either of them.
And what about parts and service for the expensive TAD 4001?
As for amplifiers, Gary Dahl uses Lynn Olson’s Amity 300B mono blocks that he built. I have Nelson Pass’s First Watt J2 and F4 ss amps. Though I’d be using a tube line stage to drive the F4 (a follower amp), most horn people say that even the best ss amps don’t sound nice with their speakers. I guess they should know.
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Hi Oltos,
Do your self a favor and don't make a science of all this.
Someone said this...someone that....
This is your hobby so enjoy the experience and start simple.
If you have not bought a specific driver yet and you want to cross over
at about 700hz there is no need to buy a 2" exit driver neither is there a need
for a big Azura Horn. I have many drivers here, even the JA-6681b on
Stereolab 400hz Horns which are one of the best Tractrix horns, but that
combination can not top my 1" Emilar EK175 or my 1" Radian drivers on the
Seos 12" CD Horns.
Try this out before you go an spend a bunch of money on drivers and horns,
especially when you want to use it with a closed chamber Altec 416.
This design would be called Econowave. It was introduced a few years back
and at the time I thought there is no way a cheap CD Horn could top a good
tractrix design. I was wrong. If you have the means to compensate for the HF loss there is no Tractrix horn, be it LeCleach, Azura, or any other, that will
sound as spacious, open and uncolored as those cheap Seos horns.
Bold a good 1" driver like the Radian 475PB or TAD 2001 on them and enjoy.
Klaus
Do your self a favor and don't make a science of all this.
Someone said this...someone that....
This is your hobby so enjoy the experience and start simple.
If you have not bought a specific driver yet and you want to cross over
at about 700hz there is no need to buy a 2" exit driver neither is there a need
for a big Azura Horn. I have many drivers here, even the JA-6681b on
Stereolab 400hz Horns which are one of the best Tractrix horns, but that
combination can not top my 1" Emilar EK175 or my 1" Radian drivers on the
Seos 12" CD Horns.
Try this out before you go an spend a bunch of money on drivers and horns,
especially when you want to use it with a closed chamber Altec 416.
This design would be called Econowave. It was introduced a few years back
and at the time I thought there is no way a cheap CD Horn could top a good
tractrix design. I was wrong. If you have the means to compensate for the HF loss there is no Tractrix horn, be it LeCleach, Azura, or any other, that will
sound as spacious, open and uncolored as those cheap Seos horns.
Bold a good 1" driver like the Radian 475PB or TAD 2001 on them and enjoy.
Klaus
And probably as many do not agree with this blank statement.
The TAD 2001 sounds more refined in the HF region than the 4001 and the
WE555 is a good example that the VC diameter has little bearing on the
sound. If absolute sound pressure is of concern than yes a bigger VC is of
utmost importance. For people that do not exceed about 110db averaged
sound pressure levels it makes no sense to shoot for a 4" VC.
What's more puzzling to me is your statement about the JA-6681b sounding
more rough than the TAD4001. With a flawless diaphragm in the Yamaha,
there is no way of it being more rough anywhere from 400hz to 12000hz
than the TAD. The TAD has the edge in ultimate HF extension and the last
bit of detail, but smoothness and musicality is the domain of the Yamaha.
No harshness anywhere.
If I would perceive any harshness with the Yamaha driver, I would buy a USB
microscope and carefully check every single leg of the Yamaha diaphragm
surround for any hair cracks.
My Emilar/Radian 1" drivers are not quite as smooth as the Yamaha JA-6681b
but the combination of the Seos with the Emilar/Radian drivers is just better
than the Yamaha with the Stereolab Tractrix. It's about synergy.
What's even more important to me, if I invite people for a listen, they don't
have to keep swapping places, because there is no sweet spot to speak off
with the Seos.
2" exit drivers with 4" VC on a Tractrix is a no go for HF pattern and quality.
That's the very reason Bruce Edgar put a tweeter on his Titan although on
paper the TAD 4001 goes as high as the Fane ST5022.
Klaus
All well and good about the Yamahas-BUT why bother examining them for cracks or any defect when there's NO more replacement diaphragms to be had anywhere? However, Gene from Radian said that they do make replacements for the TADs, and he can recommend a local service firm to install it. Btw, if I did buy a pair of TAD 2001s or 4001s, what else can die on them besides the diaphragms? Also, have you actually heard any Azurahorns? FMI, but how could a 12" SEOs horn have a wider dispersion than a 16.5" diameter Azura 425? http://www.azurahorn.com/azurahorn_horns.html
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It's not about wide dispersion but uniform dispersion. What most people do
not realize is that a 1" tractrix horn starts to unload at about 4300hz. From
that point on upwards it starts to narrow it's dispersion.
A 2" tractrix starts to unload even earlier. This is the very reason why you
do not see Tractrix horns in PA short throw cabinets and this is the reason
why no two people hear the same representation in our listening rooms.
With a near catenary profile like the Seos or the H290c from Wayne you get
a uniform radiation pattern and the advantage that you can cross fire them
for optimal room interaction. A tractrix might sound better but only for one
person in a room where the earliest reflection is so late that the brain
disregards it. Who has such a room?
AFAIK, Meyer-Sound still has diaphragms for the 1401A/JA6681b Driver.
Klaus
Meyer has no diaphragms. I asked. They do trade in broken MS1401A for their latest equivalent (MS-1401M) with a big discount. $367.50 each for new drivers that otherwise cost $1100 per driver. I don't know what they will do with the old drivers, unless they have a bunch of diaphragms for personal use. 
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Meyer has no diaphragms. I asked. They do trade in broken MS1401A for their latest equivalent (MS-1401M) with a big discount. $367.50 each for new drivers that otherwise cost $1100 per driver. I don't know what they will do with the old drivers, unless they have a bunch of diaphragms for personal use.
In their repair policy they state that they exchange the whole driver if you send
in a defect unit. To me that means they still have diaphragms. It would not
make sense to exchange it for their 1401M unit as it needs a totally different
controller. All of their HF units can only be driven by the model specific
controller.
Their 1401-M is basically a re-badged Radian 800 series driver with insignificant
changes that prevents people from using Radian diaphragms.
If Meyer uses them for a replacement it really speaks for the Radian quality.
I had a pair Radian 850PB mounted on Stereolab Tractrix via an adapter.
Even in this suboptimal use they where not far behind the 6681b.
Here is the chance to get another 6681b/1401A incl. excellent 15" Speakers.
Meyer Sound 833 Studio Referance Monitiors RARE All Drivers Working | eBay
Klaus
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As we all know, regardless of how much money and expertise we may throw at a problem, even “practical” perfection can be hard very hard won. One frequent reason for this are simple compatibility issues. For example, Lynn Olson and Gary Dahl are highly accomplished designers and they collaborated on Gary’s “Beyond the Aerial” speaker system. And even though their sonic preferences from speakers are not identical, they both love the sound of the GPA Altec 416 when used as a midwoofer. http://www.diyaudio.com/forums/multi-way/100392-beyond-ariel-781.html So Gary put them in 3 cu ft sealed boxes with rounded corners to minimize diffraction where their response is cut off below 70Hz, thereby minimizing IM distortion. Though never hearing 416s (except many years ago in movie theatre VOTTs), I was so taken with Gary’s unique application of these special drivers that I had Jim Salk clone them, as I was resolved to use them for whatever speaker system I would ultimately choose to build.
However, just before moving to order the horns, drivers and crossover parts for Jim to clone the rest of Gary’s speakers, I “did myself a favor” and mailed Gary at least 65 uncompressed WAV files of CD track rips from my collection. Two weeks later I got Gary's crushing news that his system found at least 67% of them to be poor sounding and fatiguing to sit through. Either too much compression was used, mixes that were improperly panned and “congested” orchestral passages. And some were very noticeably distorted, Gary said. He will be checking his system for any self-generating noise and distortions, but I’d be very surprised if he found any such problems.
Gary does suspect that the Yamaha JA6681B drivers may be somewhat forgiving of my recordings than his Radian 745 Neo Be. If yes, then he said that I could then switch in a HP filter for a pair of RAAL Lazy ribbons when playing my good recordings. This seems like a pretty good solution all around. Unfortunately, Meyer Sound’s reply to my email this week said they offer zero support for 6681B and 6670 drivers. Apparently, no one else does either, so I can’t risk going with the Yamahas.
So I need to find a HF/MF range driver solution that won’t make my poor recordings virtually unlistenable without dumbing down the sound quality of my great ones, and drivers that don't lack replacement parts and service. But there also are dispersion compatibility issues. Both the Radian and Yamaha drivers fit the 1.4” aperture of the Azura 425, which Lynn Olson had ordered built for Gary’s BTA speakers, as stated here.
Azurahorn -Le Cleac'h Acoustic Horns - Products
After Lynn had Bjorn Kolbrek analyze this horn Contact and together with Gary’s impedance dispersion plots of the Altec 416 they envisaged the system would work as predicted. http://www.diyaudio.com/forums/multi-way/100392-beyond-ariel-737.html
http://www.diyaudio.com/forums/multi-way/100392-beyond-ariel-1099.html
While perhaps quite atypical for a 15” driver, the Altec 416’s dispersion begins to narrows at very close to 1kHz. As for dispersion “uniformity” between drivers, again I would presume that Gary and Lynn would not have chosen the Azura 425 and the Altec 416 if they were not compatible in this regard.
These horns are very intriguing
Denovo Audio SEOS-12 Waveguide 2/3 Bolt Matte with 1-3/8"-18 TPI Adapter The SEOS? Project DIY Sound Group
But beyond passive filter construction, as I no longer have time to even learn how to do crossover simulations and system measurements, I need to rely on Jim Salk, who has my Altec 416s and his version of Brian Ding’s Rythmik 12" sealed servo subs to finish doing it all.
Gary plays his Altecs from 70Hz to 700Hz. Can your horns play low enough to cross with the Altecs without frequency response or other problems?
If yes, I could have Jim clone your horns and cross them with Altecs, but would their dispersion patterns be as compatible with Altecs as are the Azura 425s?
However, even if your horns’ dispersion were uniform with the Altec 416 midwoofers, might your drivers make my bad recordings sound as bad or even worse than they do on Gary’s system?
http://www.diyaudio.com/forums/multi-way/210931-benefits-drawbacks-waveguides.html
Btw, are your speakers active or passively crossed? What’s the make and model of your horn drivers?
And what amplifiers are you using to drive your horns and the drivers below them?
Are you perfectly happy with your horns?
http://www.diyaudio.com/forums/multi-way/210931-benefits-drawbacks-waveguides.html
If you had my music source material issues and the Altec 416 midwoofers and had between ~ $1K and $2.2K to spend on a pair drivers and horns, which make and model of each would you choose? Thank you.