I've thought about this (though never done it). Having used paper cone drivers that sound great, but have terrible break up modes requiring high order crossovers, which I'd rather not use. I've determined that it would require too much time and equipment for me to get meaningful objective results at this time.
(If only I knew somebody willing to do such "interesting" work! (for free)) !!
(If only I knew somebody willing to do such "interesting" work! (for free)) !!
Pro, would you happen to have "before and after" data for that driver?
I have this one in mind..(Happy to send one over if we agree).
https://www.diyaudio.com/community/attachments/phl-1630-pdf.745026/
I'm thinking of using it in a design as a MTM (freq range say 400hz to 2Khz approx) with an upper bass and then lower bass/sub drivers.
I have this one in mind..(Happy to send one over if we agree).
https://www.diyaudio.com/community/attachments/phl-1630-pdf.745026/
I'm thinking of using it in a design as a MTM (freq range say 400hz to 2Khz approx) with an upper bass and then lower bass/sub drivers.
I have the Revel Ultima Salon 1's.
When I got them a few years ago one of the titanium 4" mids was very distorted sounding and the other made no sound. When I pushed carefully on the cone the one that distorted moved in and out but not smoothly. The one that did not make any sound did not move at all. I had imagined a fried up voice coil seized in the gap. Since they were useless the way they were I decided to take them out and see what could be done.
If I remember correctly I used screws that were slightly larger then the securing holes in the frame to grab or bite into the frame. You can then, very carefully while protecting the cabinet face, pry the speaker frame out a little at a time working around the driver frame. Doing it this way the driver came out pretty easily. I think the frame was stuck to the cabinet with some sort of mastic/putty.
I checked the continuity of the voice coil and to my surprise they were not open.
I then set about removing the spider and surround from the frame. This was a very time consuming process that involved some not so good to breath chemicals (acetone, mkp....)
and a lot of patience.
Eventually, I go them apart and found the VC gap filled with metal dust. Once cleaned the voice coils themselves looked to be in fine shape. After cleaning out the gap and gluing it all back together they worked great.
After reinstalling them and testing the speakers for a bit with a standard DIY First Watt F5 I put them in storage until I could make a F5 Turbo V3 (which I'm working on now) to power them properly so I don't know how long the fix will last.
From what I understand each speakers crossover was "tweaked" for each speaker. Wanting to keep them as original as possible I was willing to repair them. I remember searching around on the web and there did seem to be some owners that had found some suitable replacements but, by now, even those are probably out of production.
From the limited listening I did they did sound very good with the bass being very, very good.
I dug up a few pictures from the operation.
Hope this helps.
When I got them a few years ago one of the titanium 4" mids was very distorted sounding and the other made no sound. When I pushed carefully on the cone the one that distorted moved in and out but not smoothly. The one that did not make any sound did not move at all. I had imagined a fried up voice coil seized in the gap. Since they were useless the way they were I decided to take them out and see what could be done.
If I remember correctly I used screws that were slightly larger then the securing holes in the frame to grab or bite into the frame. You can then, very carefully while protecting the cabinet face, pry the speaker frame out a little at a time working around the driver frame. Doing it this way the driver came out pretty easily. I think the frame was stuck to the cabinet with some sort of mastic/putty.
I checked the continuity of the voice coil and to my surprise they were not open.
I then set about removing the spider and surround from the frame. This was a very time consuming process that involved some not so good to breath chemicals (acetone, mkp....)
and a lot of patience.
Eventually, I go them apart and found the VC gap filled with metal dust. Once cleaned the voice coils themselves looked to be in fine shape. After cleaning out the gap and gluing it all back together they worked great.
After reinstalling them and testing the speakers for a bit with a standard DIY First Watt F5 I put them in storage until I could make a F5 Turbo V3 (which I'm working on now) to power them properly so I don't know how long the fix will last.
From what I understand each speakers crossover was "tweaked" for each speaker. Wanting to keep them as original as possible I was willing to repair them. I remember searching around on the web and there did seem to be some owners that had found some suitable replacements but, by now, even those are probably out of production.
From the limited listening I did they did sound very good with the bass being very, very good.
I dug up a few pictures from the operation.
Hope this helps.
Attachments
Thank you Mazz for your informative post. I think many owners will find it very useful. Shame to say, though I had paid a deposit and arranged to buy a pair of Salon 1's, in the end because of the problems with the 4" mid decided against, (who knows what may happen to the other drivers). I was quite surprised at the lack of spares cover for such a high end and expensive product.
I’ve turned my attention now to a homemade high efficiency four way, (I’ve always found hi eff more revealing), with low order crossovers, and easier to be driven with class A or valve electronics. This will take some time due to other commitments, though I like to get my ducks in a row before I start.
I’ve turned my attention now to a homemade high efficiency four way, (I’ve always found hi eff more revealing), with low order crossovers, and easier to be driven with class A or valve electronics. This will take some time due to other commitments, though I like to get my ducks in a row before I start.
Yes. It is a too bad that these fine speakers did not have better customer support. It pains me to think of how many of them may have ended up in the grave because of this problem. Maybe it had something to do with The Harman Group takeover, who knows? Anyway, just wanted people to know that there is some hope for the mid drivers being fixed.
Good luck with your new build!
Good luck with your new build!
Mazz.
Just asking about the metal dust shown in your picture, what do you think it was, and/or where was it from? Could it have been from the magnet possibly?
Just asking about the metal dust shown in your picture, what do you think it was, and/or where was it from? Could it have been from the magnet possibly?
Jotom,
It looked to me like the voice coil former is made of aluminum. If you look closely at the pictures at the inside of the former you will notice marks that would indicate rubbing. My thinking is that the inside of the former was rubbing on the pole piece. This is backed up by the fact that the voice coil wires were total fine, no signs of rubbing. In the battle between the aluminum and the pole piece it looked like the pole piece was loosing. The dust in the gap has a character more expected with a ferrous type metal. My guess would be that once a little dust was created it just stayed in the gap making it more and more abrasive and creating more and more dust until it seized. Thinking back on it, it must have been the pole piece because the dust was magnetic and was not easy to get out of the gap. My hope is that with the extra space created by the rubbing, now that it's cleaned out, it won't be an issue in the future......we will see.
It looked to me like the voice coil former is made of aluminum. If you look closely at the pictures at the inside of the former you will notice marks that would indicate rubbing. My thinking is that the inside of the former was rubbing on the pole piece. This is backed up by the fact that the voice coil wires were total fine, no signs of rubbing. In the battle between the aluminum and the pole piece it looked like the pole piece was loosing. The dust in the gap has a character more expected with a ferrous type metal. My guess would be that once a little dust was created it just stayed in the gap making it more and more abrasive and creating more and more dust until it seized. Thinking back on it, it must have been the pole piece because the dust was magnetic and was not easy to get out of the gap. My hope is that with the extra space created by the rubbing, now that it's cleaned out, it won't be an issue in the future......we will see.
I'm probably wrong, but would generating that much dust not cause verticle marks/scratches on the former? It looks to me that the radial marks are still intact. Also, if the former is Aluminium and the pole piece iron or steel would not the former wear first? All these points are strictly academic I suppose.
It may sound silly, but I wonder if metal dust left on the drivers after manufacture has in time migrated into the gap, which is the area of highest magnetic field ?
It may sound silly, but I wonder if metal dust left on the drivers after manufacture has in time migrated into the gap, which is the area of highest magnetic field ?
I think the ones I have are pre Harman 1998 model. I haven't pulled any of the other drivers out, only the 4" titanium mids had an issue.
I can't say for sure. I was surprised that the aluminum former did not show more ware. I was thinking the dark rings on the inside of the former were the contact areas that show the travel of the cone and voice coil assembly. The voice coil gap was very narrow so I couldn't really see down into it. I'm not sure what machining process would leave dust like that but who knows?
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Just to put some more info into this thread.
The pole piece is coated (often with nickel-mixture)
After time the pole piece ferro/Neo-magnet seems to dissolve the coating on "the weekest" area´s.
And that small pieces of coating then wear down most of the coating, which is magnetic and therefor stay´s in the gap.
Infinity MTS Prelude also have the samt problem.
I try to fix this problem, but the very strong magnetism made it superhard to do, and pole piece also was unmounted (needing centering and glue)
For me this is a manufacturing defect, which has been known since the early 80s with Infinitys EMIT and EMIM
The pole piece is coated (often with nickel-mixture)
After time the pole piece ferro/Neo-magnet seems to dissolve the coating on "the weekest" area´s.
And that small pieces of coating then wear down most of the coating, which is magnetic and therefor stay´s in the gap.
Infinity MTS Prelude also have the samt problem.
I try to fix this problem, but the very strong magnetism made it superhard to do, and pole piece also was unmounted (needing centering and glue)
For me this is a manufacturing defect, which has been known since the early 80s with Infinitys EMIT and EMIM
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Not cheep and easy fitting, but Dynaudio Esotar 430 supouse to a good replacement for the 4 inch.
The new one is here:
https://www.woofersetc.com/p-9307-e430-dynaudio-35-esotar2-series-midrange-speaker.html
But try to find a used pair of the first modell.
https://www.hifishark.com/search?q=dynaudio+esotar+430
The new one is here:
https://www.woofersetc.com/p-9307-e430-dynaudio-35-esotar2-series-midrange-speaker.html
But try to find a used pair of the first modell.
https://www.hifishark.com/search?q=dynaudio+esotar+430
The problem drivers in this speaker are
1. Midrange 4" voice coil problems from shavings due to excess heat. I'm guessing the Purifi 4" midrange would not have that heat problem.
2. Tweeter
Would be great to replace the problem midrange with a Purifi.
An added bonus, it would be great to replace the tweeter with a Beryllium tweeter.
It's a Scanspeak 2904-980000 which Scanspeak says was unmodified.