So we are talking about "faceplate" and the other thingie in kingdaddy's pics that holds the membrane -- lets call it the membrane plate.
So he means to shave the two curves of the faceplate, so that there is only one?
Does he suggest to fill up the holes in the faceplate or the membrane plate?
Before I take my XT25s apart, does anybody know if:
a) the membrane plate assembly is self-centering?
b) the phase plug thingie is glued onto the magnet, meaning some force is needed to pull it off (or cutting the membrane)?
So he means to shave the two curves of the faceplate, so that there is only one?
Does he suggest to fill up the holes in the faceplate or the membrane plate?
Before I take my XT25s apart, does anybody know if:
a) the membrane plate assembly is self-centering?
b) the phase plug thingie is glued onto the magnet, meaning some force is needed to pull it off (or cutting the membrane)?
capslock said:
Thats how I understand it.
capslock said:
The face plate.
capslock said:
If you grab the phaseplug and "rock" it you see that it moves. You can probably pull it off with a pair of pliers, but I'd rather wait and hear from kingdaddy how he did it since Duelund suggests "cut membrane free from phaseplug".
Does Duelund say what these tweaks improve?
Does anybody understand why this design (and the Scan Speak ring radiatior, too) generates this much second harmonic while having excellent third harmonic performance? I gather the mods would work on frequency response rather than harmonics.
Regards,
Eric
Does anybody understand why this design (and the Scan Speak ring radiatior, too) generates this much second harmonic while having excellent third harmonic performance? I gather the mods would work on frequency response rather than harmonics.
Regards,
Eric
I just man-handled this thing since I thought it was a lost cause and probably wouldn’t be fixable, basically I just removed the face plate to gain access to the membrane assemble then pulled the membrane assembly off with a little force, the membrane inverted and looked like it was going to tare out of the plastic, but to my surprise this thing is nearly indestructible, this membrane is tough as nails, at first it looked wrinkled and damaged beyond repair but it just snapped back to its original form when it pushed it back into place with my finger.
At first I tried to cut around the Phase Plug to separate it from the membrane, but I slipped with the razor and sliced across the membrane with quite a bit of force (maybe my razor was dull) and to my surprise the blade did not damage the membrane, only a light score mark could be seen. After that I just pulled on the whole membrane assembly until the membrane was nearly inside out with the pulling force and it separated from the magnet.
If you look closely at the picture you can see the tiny indentions in the silicone glue on the magnet assembly around the voice coil, this is where the former (spider thingy inside the VC) that is attached to the front side of the phase plug was glued, and the guide pins on the magnet assembly will auto align the membrane VC assy in the gap exactly into the original indentions in the silicone glue. Just add a tiny touch of clear silicone over the old indentions and it will affix in the exact original location, then the faceplate will sandwich the whole thing together.
I hope this is clear, its actually kinda hard to explain, but be comforted by the fact that this is a very robust tweeter and you don’t have to be too easy with it, it’s very hard to permanently damage.
At first I tried to cut around the Phase Plug to separate it from the membrane, but I slipped with the razor and sliced across the membrane with quite a bit of force (maybe my razor was dull) and to my surprise the blade did not damage the membrane, only a light score mark could be seen. After that I just pulled on the whole membrane assembly until the membrane was nearly inside out with the pulling force and it separated from the magnet.
If you look closely at the picture you can see the tiny indentions in the silicone glue on the magnet assembly around the voice coil, this is where the former (spider thingy inside the VC) that is attached to the front side of the phase plug was glued, and the guide pins on the magnet assembly will auto align the membrane VC assy in the gap exactly into the original indentions in the silicone glue. Just add a tiny touch of clear silicone over the old indentions and it will affix in the exact original location, then the faceplate will sandwich the whole thing together.
I hope this is clear, its actually kinda hard to explain, but be comforted by the fact that this is a very robust tweeter and you don’t have to be too easy with it, it’s very hard to permanently damage.
Attachments
Hi Kingdaddy,
thanks for that account. I understand now you basically forced the phase plug off and it would be clear how to reinsert it in exactly the same position.
However, the VC position is probably as much governed by the positioning of the membrane plate. Is there anything that defines its position?
Thanks!
thanks for that account. I understand now you basically forced the phase plug off and it would be clear how to reinsert it in exactly the same position.
However, the VC position is probably as much governed by the positioning of the membrane plate. Is there anything that defines its position?
Thanks!
Does the "needle" of the rear chamber have any connection to the phase plug? This would be helpful to know before one takes off the chamber.
Is there any padding in the chamber?
By the way, what good are these star things around the base of the phase plug assembly? Their ends would come close to the inside of the VC former, but it's hard to see why they are needed.
Is there any padding in the chamber?
By the way, what good are these star things around the base of the phase plug assembly? Their ends would come close to the inside of the VC former, but it's hard to see why they are needed.
The star things hold the phase-plug in place while being acoustically transparent.
If you go to the Audiophysic webpage (www.audiophysic.de) then you will come across the notion of the backchamber several times. They don't supply any details though but you can be sure that they added damping material.
Regards
Charles
If you go to the Audiophysic webpage (www.audiophysic.de) then you will come across the notion of the backchamber several times. They don't supply any details though but you can be sure that they added damping material.
Regards
Charles
XT25 & 15W/8530-00
I am currently designing a crossover using the above drivers. The 8530 is first order 1.8mH coil and an LCR trap 1.8mH, 33UF and 7.5ohm. The Xt25 is third order electrical 5.2uF cap, 0.2 mH coil, 7.7uF cap. Current Lpad 8ohm parrallel & 15ohn series.
I cannot say that this is definitive I have no software and am still tweeking, but its the best I've come up with. Far superior to the Acoustic Reality crossover that got so much attention some months ago.
Good Luck and let me know what you think if you try this out.
John W
I am currently designing a crossover using the above drivers. The 8530 is first order 1.8mH coil and an LCR trap 1.8mH, 33UF and 7.5ohm. The Xt25 is third order electrical 5.2uF cap, 0.2 mH coil, 7.7uF cap. Current Lpad 8ohm parrallel & 15ohn series.
I cannot say that this is definitive I have no software and am still tweeking, but its the best I've come up with. Far superior to the Acoustic Reality crossover that got so much attention some months ago.
Good Luck and let me know what you think if you try this out.
John W
Per Nielsen said:I have now done Steen Duelunds upgrades, and it seems to be working very fine, I will post pictures later this week when i get a cam
If I put on an extra magnet could that harm the unit in any, way ,or only improve it???
What kind of glue did you use on the VC former and on the membrane/phase-plug(or did you tear it apart as kingdaddy did?)
An extra magnet will increase sensitivity
I've used it too, and it's an interesting beast.
I have been playing with that tweeter for a while now, and I've used it in one design which I have on my web page. It's a modification of the North Creek Okara mini-monitor.
http://quadesl.com/okara.shtml
My friend Keith has also been playing with that tweeter, and has some information on it on his web site:
http://mywebpages.comcast.net/kidder/Audio/audio.htm
Specifically in his very good 411 3-way speakers:
http://mywebpages.comcast.net/kidder/Audio/4eleven/411.htm
My experience with this tweeter is only with passive crossovers. I found that I had to cross it over pretty high and pretty steeply. The tweeter really thinks it's a midrange and wants to keep playing, although when I tried to cross it over too low it started to sound harsh and strained. To my ears it needs to be crossed over like a 3/4" tweeter, but it really tries to play like a little midrange unit.
Also when I was crossing it over it just didn't want to roll off. I ended up slapping it down with a third order electrical crossover (plus l-pad). Other folks in the Albuquerque speaker club have also been playing with it and also found that it really needed to be crossed over pretty steeply.
I do like the idea of active crossovers, I should try that one of these days.
Sheldon
I have been playing with that tweeter for a while now, and I've used it in one design which I have on my web page. It's a modification of the North Creek Okara mini-monitor.
http://quadesl.com/okara.shtml
My friend Keith has also been playing with that tweeter, and has some information on it on his web site:
http://mywebpages.comcast.net/kidder/Audio/audio.htm
Specifically in his very good 411 3-way speakers:
http://mywebpages.comcast.net/kidder/Audio/4eleven/411.htm
My experience with this tweeter is only with passive crossovers. I found that I had to cross it over pretty high and pretty steeply. The tweeter really thinks it's a midrange and wants to keep playing, although when I tried to cross it over too low it started to sound harsh and strained. To my ears it needs to be crossed over like a 3/4" tweeter, but it really tries to play like a little midrange unit.
Also when I was crossing it over it just didn't want to roll off. I ended up slapping it down with a third order electrical crossover (plus l-pad). Other folks in the Albuquerque speaker club have also been playing with it and also found that it really needed to be crossed over pretty steeply.
I do like the idea of active crossovers, I should try that one of these days.
Sheldon
We've use the XT25 in a couple of designs.
Using a passive high order Cauer/Elliptical filter, these designs are XOed at 1.25kHz
The M8a-MKIV is a rear ported TM design. It's design and construction will be featured in an upcoming issue of AudioXpress
The Arvo Pärt prototype is an all dipole design created last summer.
Using a passive high order Cauer/Elliptical filter, these designs are XOed at 1.25kHz
The M8a-MKIV is a rear ported TM design. It's design and construction will be featured in an upcoming issue of AudioXpress
An externally hosted image should be here but it was not working when we last tested it.
The Arvo Pärt prototype is an all dipole design created last summer.
An externally hosted image should be here but it was not working when we last tested it.
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