Info on the Yamaha JA-6681 compression driver

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Certainly. Radian 745Neo Be, equalized for the horn. Love them.
Yesterday I picked up a pair of TAD 4002 that I will compare the Radians to, sometime in the new year. It is unclear which will sound best. 3” diaphragm 1.4” exit versus 4” diaphragm 1.5” exit. Each to get custom EQ and custom throat adapter made for the TH4001 horn.
 
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Yes you are right it was not the S4115 where I got my JA6603 out of.
Mine looked like it but had a bullet tweeter
next to the mid horn (JA4205) I think.
Do you know which monitor this was?
Bass speaker and horn was black not white.
Yamaha introduced the JA-0506 "bullet tweeter" in 1973, they may have been used in some form of "NS" (Natural Sound) monitors, none of which I've ever seen in real life or on line.

Other than Meyer Sound floor monitors using some variant of the JA6681, never have seen any cabinets using them.
 
I really want to know which cabinet it was, as I
need another phenolic diaphragm to
experiment with.
Back then I didn't pay attention what model
monitor I purchased. I salvaged the
components and dumped the cabinets.
My cabinets where originals that's for sure because you can't run the JA6603 without a
tweeter as it only reaches to 8khz.
All I know is that I had seen a few of the same
cabs on a Canadian listing.
Here is a picture of the tweeter that I have just taken this morning. Same sonic signature as a EV T350 but not as detailed and refined as my Fane.
IMG_20231216_100658.jpg


IMG_20231216_100753.jpg
 
Certainly. Radian 745Neo Be, equalized for the horn. Love them.
Yesterday I picked up a pair of TAD 4002 that I will compare the Radians to, sometime in the new year. It is unclear which will sound best. 3” diaphragm 1.4” exit versus 4” diaphragm 1.5” exit. Each to get custom EQ and custom throat adapter made for the TH4001 horn.
Do you think the midrange is as good as from the 6681?
How low are you using the 745?
 
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Do you think the midrange is as good as from the 6681?
How low are you using the 745?
Oh yes, there is no turning back. I feel spoiled by these 745 Be-auties!
On TH4001 they are crossed just above 700 Hz.
Violin, strings, intelligibility are remarkable, IMO of course.

Since this is a thread on the yammies it might be worth mentioning that the 6681 response, when matched to the AH425, is pretty much flat without any EQ. This makes them an easy driver to work with, that sounds pleasant out-of-the-box.
 
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So we come to the question which woofer system? Onken or Petite Onken. Fantastic quality (but use high quality ply). Or large open baffle with one or two 15" woofers. But bi-amped! No passive network. They do just way way too much damage.
Has anyone ever heard the Yamahas in open baffles? If yes, please describe the experience and the implementation.
 
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I've yet to have any opportunities to hear the 6681B, and with time quickly running out on choosing alternates I must turn to long time users for their assessment of this driver. I'd either be using it in a TH4001 (plus tweeter) or JMLC A425 or A340
horn above sealed Altec 416-8B woofers.

Range of 1 to 10 = best:

Soundstage Depth --- /10

Soundstage Width --- /10

Vocal Clarity Female --- /10

Accurate Musical Instrument timbre --- /10

Coherence between midrange and treble --- /10

Clarity of midrange and lower treble --- /10

Sense of Dynamic Range --- /10

General Thoughts on Sound Character

Range of 1 to 10 = most:

Soft --- /10

Warm --- /10

Neutral --- /10

Relaxed --- /10
 
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Please chime in if you have any objection, suggestion, for the following procedure:

1. Cut the copper beryllium foil into 100mm x100mm shape.
2. Put for 30minutes in 300° Celsius pre heated oven, between milled 100mm x100mm iron blocks to get an absolotley flat piece.
3. Clamp foil between appropatate diameter disks with 5mm over hang and route outer diameter.
4. Clamp foil on Donut shaped milled disks of 70mm inner hole to mill inner diameter.
5. Mill S-shaped fingers in between the kind of clamp as seen in picture
Here at post # 1880, Arez may offer valuable info on the what was likely the original finger material Yamaha had used-and perhaps suggestions for us what would likely be an excellent or even superior substitute today.
https://www.diyaudio.com/community/...rivers-today-2022.382609/page-94#post-7601351
 
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The Yamaha JA4281b Alnico Tweeter. I have a pair to sell.
Fair condition. JBL 2405 shown for size comparison. $300 USD plus shipping.for the pair.
Big , heavy , and nice.
 

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