Info on the Yamaha JA-6681 compression driver - Page 14 - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way

Multi-Way Conventional loudspeakers with crossovers

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 8th July 2013, 11:39 AM   #131
3GGG is offline 3GGG  Australia
diyAudio Member
 
Join Date: Mar 2010
Quote:
Originally Posted by Rewind View Post
Good luck. You have to let us know how the 15Hz horn sound crossed so high.
Will be interesting to see the output, but Jean Michel claims output to 350Hz without active correction, so 120Hz should be fine.
  Reply With Quote
Old 11th July 2013, 07:34 AM   #132
Rewind is offline Rewind  Sweden
diyAudio Member
 
Join Date: Jan 2009
BTW, beryllium is white. The fingers are mostly copper. Don't be fooled by sleak 1980's marketing.
Attached Images
File Type: jpg s9s.JPG (24.3 KB, 233 views)
  Reply With Quote
Old 11th July 2013, 12:45 PM   #133
3GGG is offline 3GGG  Australia
diyAudio Member
 
Join Date: Mar 2010
Quote:
Originally Posted by RB_Login View Post
3GGG, I would like to recommend you to think again about building a 15Hz horn as it is a bit contra-productive thing to do regardless of the horn design. For sure you can do whatever you want but I have a lot of experience of the subject. If you want your midbass horn for go down very low then do not target 15Hz but rather 35-45Hz. You will need to use close -bottom ULF section at the bottom regardless. If you do have midbass 3 octaves horn you will not be able to “stop” it properly.
Thanks, to clarify the Fane will stay in the MIdbass 160Hz horn and the Bass horn will be another separate ULF channel with an 18" driver.
  Reply With Quote
Old 11th July 2013, 01:47 PM   #134
Radian is offline Radian  Germany
diyAudio Member
 
Join Date: Jun 2004
Location: Wiesbaden
Quote:
Originally Posted by RB_Login View Post
I am sorry what you saying might be accurate from general stand point but it does not back you your allegation that Romy upperbass channel with Fane is not done properly, First of all how do you know what horn Romy uses? Then, how do you know what Romy’s objectives were and what result he has. Why do you feel that Fane even need a phase plug? The Fane in this horn has extension all over 5K and phase plug just will push it to 8K. It is very difficult passive low-pass filter this driver as it has a lot of inductance, if so why would anybody ever want to extend the HF of this driver. Romy uses his upper bass horn up to 600Hz, why do you feel he would need to have more HF extension and phase plug? Did you use the Fane driver yourself? I wonder what rational you have to advocate that Romy horn was not done properly if you do not understand what the channel does.
Woha, Cool down please,
1. This is only my opinion and not to be taken as gospel.
2., Romy has posted pictures and drawings of his horn and there is nothing
we don't know about it.
3. He has been using it, at least for a wile, all the way up to about 1,2 khz
as far as I know.
4. John Hasqin has build Romy's horn. It's a simple tractrix contour. Nothing
special. John is one of the most respected people when it comes to horn
speakers especially tractrix and it's iterations. He himself has stated several
times that the Fane would benefit from a phase plug .
4: There are plenty white papers on the net that show how important it is to
get the compression ratio and throat design right for ultimate performance.
5. Common sense and a the study of nature is all it needs to understand that
letting a cone even if only partially push against a flat piece of board is not
very wise and will cause a number of unwanted effects even in the lower
mid region.
A teacher in the field of hydraulics or aerodynamics would shake his head
upon the way this design tries to achieve the compression.
The throat is a high pressure/low velocity region that needs a passage as
smooth as possible to prevent unwanted turbulences which are in regard to
sound waves just phase and amplitude irregularities that our ears are
sensitive to.
Anyone who believes that these are not audible in the range this horn works
in is in my opinion naive.
It's easy to see that my proposal is not about a simple phase plug that
achieves a better hf behavior.

Klaus
  Reply With Quote
Old 11th July 2013, 02:12 PM   #135
Rewind is offline Rewind  Sweden
diyAudio Member
 
Join Date: Jan 2009
I have thought about it, how this straight wall between the Fane and the horn may not be the best thing, but I was clueless how to solve it. It should not be so difficult to manufacture a longer compression chamber before the horn. I do however wonder about the necessity of the actual plug.

Then I also wonder about the necessity of the Fane driver at all, used together with the JA6681b. The Fane driver could cover for example 120-280Hz, then taken over by the JA6681b 280-12kHz. I admit the JA-6681B does sound a little strained here, but inctedibly detailed. I can always cross the cone driver a little higher if it ever becomes too strained. My point is that the Fane is good if your CD only goes down to 500Hz. But if the CD handles low frequencies good then why use a cone driver there.

Would not a 10 or 12 inch be better?

Last edited by Rewind; 11th July 2013 at 02:21 PM.
  Reply With Quote
Old 11th July 2013, 06:26 PM   #136
Radian is offline Radian  Germany
diyAudio Member
 
Join Date: Jun 2004
Location: Wiesbaden
The JA6681b will always be a compromise on a horn monster like the Azura.
Just a little to thin on the bottom and a lousy pattern control from about 2500hz on up.
My 400hz tractrix horn does not come close to a good constant directivity horn
like the cheap $35 SEOS in regards to naturalness and hf sweetness.
I was so exited to have a tractrix horn after the rave
reports and the work of people like Bruce Edgar who reignited the fire for the almost forgotten
horn contour. A few years ago Zilch tried to tell us horn lovers that there is even a
better way to use a compression driver, but who wants to listen if he thinks he already
has the state of the art mid horn. When I finally heard a Radian 1 inch driver on a good
CD horn I was no longer thinking I had reached the pinnacle of mid frequency reproduction
with the tractrix contour. It's not only about beaming that is disadvantageous in a
big tractrix horn. It's something that makes it less natural sounding compared to a
good CD horn. The lowest frequency for a good CD horn is about 1000hz according to
the late Zilch and some others. For frequencies from let's say 200hz on up to this 1khz
there is a way cheaper compression driver and one that is stronger in this range.
It is the Klipsch K55/Atlas PD5V. The diaphragm can make 1mm excursion. The WE555
is in actually the same driver with a field coil and an aluminum diaphragm and it was used
on the A16 below 100hz!!!
If one likes to use a compression driver for duty below 500hz that would be the current
best choice except for the boutique drivers like Goto, Ale or YL which are out of most peoples
budget. I really aprechiate the works of people like Bruce Edgar and JMLC but time goes on
and better horn contours are being discovered. That's life.

Klaus
  Reply With Quote
Old 11th July 2013, 09:58 PM   #137
expert in tautology
diyAudio Member
 
bear's Avatar
 
Join Date: Apr 2002
Location: New York State USA
The PD5V and the WE555 do not seem identical to me.

I think the only thing that is truly identical is the diameter of the VC!

Beyond that, I think the similarities diverge significantly. Otoh, I have heard the PD5V sound very nice in the midrange, but it won't cover the range that the 555 will, afaik.

_-_-
__________________
_-_-bear
http://www.bearlabs.com -- Btw, I don't actually know anything, FYI -- [...2SJ74 Toshiba bogus asian parts - beware! ]
  Reply With Quote
Old 12th July 2013, 07:01 AM   #138
Radian is offline Radian  Germany
diyAudio Member
 
Join Date: Jun 2004
Location: Wiesbaden
Quote:
Originally Posted by bear View Post
The PD5V and the WE555 do not seem identical to me.
I think the only thing that is truly identical is the diameter of the VC!
Beyond that, I think the similarities diverge significantly. Otoh, I have heard the PD5V sound very nice in the midrange, but it won't cover the range that the 555 will, afaik. _-_-

Actually they are identical. You can swap the diaphragm from one driver to
the other. As I said before, I suggested in the German analog forum to play
with that driver till it does what a W555 can do and Dietmar an experienced
horn fellow who is retired had done exactly that. A bigger back chamber and
a litte change of the compression ratio got him this output on his Sato horn:

Distortion D2 0,4%, D3 0,04% !!!
Attached Images
File Type: png K55.png (159.2 KB, 193 views)

Last edited by Radian; 12th July 2013 at 07:08 AM.
  Reply With Quote
Old 12th July 2013, 07:23 AM   #139
Radian is offline Radian  Germany
diyAudio Member
 
Join Date: Jun 2004
Location: Wiesbaden
Now that's a driver who is really fit to cover the lower region. Much
more so than the JA6681b.
A system with JA6681b on an Azura can not achieve the performance
of a Sato with K55 and a decent 1" driver like Emilar, Radian or TAD on a CD horn.
Non critical crossover points and a pretty uniform radiation pattern all the way up,
can not be beat sonically by any big tractrix horn no matter how hard anyone tries.

Klaus

Last edited by Radian; 12th July 2013 at 07:27 AM.
  Reply With Quote
Old 12th July 2013, 07:29 AM   #140
Rewind is offline Rewind  Sweden
diyAudio Member
 
Join Date: Jan 2009
Radian: Here is a guy talking about the Klipsch K55, and possible replacements. Seem like he thinks the K55 is not good enough below 500Hz, and that a 2" replacement CD is needed.

Klipsch loudspeaker corner
"1 Inch or 2 Inch drivers ?
Should I spend the extra money for a 2 Inch throat driver and horn? They say that a 2 inch horn is supposed to be better. The truth is that this is quite true, but the difference is hard to measure at normal listening levels. Look at the intermodulation distortion plots of a 1 inch driver on a 1-inch horn versus a 2 inch driver on the 2 inch horn. The small "spikes" on the bottom line are the distortion products. This illustrates how even a high quality 1-inch driver will overload when used on a Klipschorn at moderately high levels. There is no quality 1-inch driver that will handle 400 Hz without distorting the sound. These drivers all have light metal diaphragms designed to go up high in frequency. They won't go down like the phenolic diaphragm in the stock K55 will. The only drivers that will are 2 Inch drivers! The Klipschorn squawker driver needs to handle the 450 Hz tone because the woofer won't go up that high. The Belle Klipsch and LaScala can be crossed over at 500 Hz. The 450 Hz tone would go to the woofer, so the Belle and LaScala don't have this problem to such a degree.

The real reason to move to a 2-inch horn is to allow a better driver than the stock K55 to be used. This is why a 2-inch horn is being suggested, not to extend the lower limit of the midrange! There is simply no 1-inch driver that will do! The B&C DCM50 driver is being offered for 2-inch horns. It was designed for the 400 Hz crossover required by the Khorn."

Last edited by Rewind; 12th July 2013 at 07:39 AM.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Singles party! Pioneer PD-801 Yamaha JA-6680 Renkus-Heinz SSD 3301 maravedis Swap Meet 11 3rd July 2012 12:13 PM
any info,manual about Yamaha B-2 ? elviukai Solid State 59 18th May 2010 01:41 PM
Yamaha Compression drivers JAMES@BOYD.ORG Multi-Way 6 14th April 2010 06:52 PM
replacement for Yamaha JA-0510 tweeter Scorp50 Vendor's Bazaar 0 12th December 2007 06:56 AM
FS: Silver Iris Coaxial 15" driver pair (sans XO and compression driver) theAnonymous1 Swap Meet 0 24th April 2007 12:09 AM


New To Site? Need Help?

All times are GMT. The time now is 10:43 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2