Sad thing about EMIM's

Jarre

Member
Hi all!

I just wrote these words on the Yahoo group for Infinity and it's some serious information to You all with EMIM's.

"Sadly enough, I have to enlighten You all about some serious production failures
or should I call it lack of IPC (In Process Control).
The big problem lays in the result after the form punch for the magnet plate.
The result is the punch twists the 3 5mm narrow rows that the magnets are glued
to.
The end result is that the magnets are NOT placed in a flat manner in relation
to each other and thus causes an uneven magnet field and serious problematic spacing reduction for the membranes movement.

This will then result in distorted sound when turning up the volume as the
membrane WILL hit the magnets.

If You like I can put up some pictures of this.

I own a pair of Infinity RS1b and actually bought an extra EMIM from ebay to
check. The issue on that one was the same.

So, I have the big work in front of me to remove the magnets and realign/flatten the 3 rows on every magnet side of 14 EMIM's.
"

Cheers and sorry for this bad news!

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Sad thing about EMIM membranes.

Hi again!

Just wanted to give You all some heads up on EMIM membrane problems.

As most of You know, the membrane of an EMIM needs the space between the magnet plates for movement and thus it NEEDS to be perfectly flat.
I have seen a lot of sales out there on Ebay where You clearly can see waves on the membrane.
Those membranes are shot and ready for the trash!
What those membranes will suffer from is hitting the magnets or even resting on the magnets.
The result is harsh sound and tiresome for the listener for longer periods of time.

Sad info, I know. But this is the facts.
I got the result and answer by taking the step and replace ALL of my EMIM's with new ones from Graz (Apogee Acoustics).
The difference was EXTREME!

Here is a video of one example of a wavy membrane.

https://plus.google.com/photos/115553154151824436446/albums/5853623800252573521/5961411366653210834?pid=5961411366653210834&oid=115553154151824436446
 
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I just checked my RS4.5's and all of the magnet frames in the EMIM's are flat using the back of a razor blade as a reference. Also the magnets in strips 2 and 4 have black felt stuck to the back of them so it's virtually impossible for the diaphragms to rub on the magnets. My EMIM's have those ripples in the mylar which I believe are caused from stretching but I have not heard any adverse effects with the sound to date. So I must be one of the lucky ones ;)
 
I just checked my RS4.5's and all of the magnet frames in the EMIM's are flat using the back of a razor blade as a reference. Also the magnets in strips 2 and 4 have black felt stuck to the back of them so it's virtually impossible for the diaphragms to rub on the magnets. My EMIM's have those ripples in the mylar which I believe are caused from stretching but I have not heard any adverse effects with the sound to date. So I must be one of the lucky ones ;)

Well, the membrane should not even be able to hit the magnets. Not because of electrical failure but because it means excursion breakdown that leads to distortion.

But if this is nothing You can hear, then it's all good I guess though the fact stating another thing.
 
Well, the membrane should not even be able to hit the magnets. Not because of electrical failure but because it means excursion breakdown that leads to distortion.

But if this is nothing You can hear, then it's all good I guess though the fact stating another thing.

I think that over time the diaphragms stretch and are more prone to hitting the magnets but the felt on the magnets on my EMIM's seem to quiet down the rubbing so it is not so noticeable.
 
If you want to stay happy with your vintage EMIMs, avoid playing solo piano on your system.

Yes, I would think that piano would identify the obvious problems and I know that solo harp is also an excellent instrument to identify distortion from crappy membranes or loose wires on Magneplanars.
 
Jarri Never seen them twisted like your's, The dude;s on the punch press didn't take care of the dies and keep them sharp and flat.
Thats a major job you got on your hands
Al
 
I re-did all my EMIMs a few years ago and they were all nice and flat. Looks like it may have been an occasional problem rather than chronic.
 
I agree that it is extremely strange but serious.

As I mentioned, I actually bought an extra EMIM driver from ebay and that one looked exactly the same with twisted bars.
What are the odds of that?

Here is the back of a naked EMIM (without the damping mesh).
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Most of my EMIM membranes are nice and flat, but a few (esp. on one of the RS 2.5s) have some visible degree of rippling. Not severe, only minor, but it's there. It doesn't seem to affect the sound, but that said, I rarely over-crank the volume, so I may not be driving them hard enough to cause trouble with magnet contact.

I've seen a few over the years that looked pretty bad, but have managed not to buy those. I've also seen some with what looked like rust spots on the traces, and saw one recently that had fairly severe scratches across the traces. The seller of that one said all the drivers worked and sounded great, but visually I couldn't see how that one could work unless one repaired the trace where the scratch appeared to completely sever it. I didn't buy that one, but I might have, because otherwise the speakers were in great shape, and the trace could be repaired if necessary.

As for the magnets, I'm going to have to double-check the alignment on the EMIMs on my RS 2.5s, as part of the overall restoration of them.

Fortunately, the EMIMs on my Gammas are, as nearly as I can tell, in "gorgeous" shape, clean, aligned, flat, etc... But at some stage I'll probably take them off, take them apart and check them, too. Better to know what you have than to sort of know and assume, and better to put something in absolutely correct shape, than to live with something inferior yet correctible.

Everyone who has the Graz membranes raves about them. I'll probably get them at some stage (when he does another production run), but the expense is a bit of a pain when you have multiple EMIMs to do!

Thanks for the heads-up on these issues.
 
Yes, the Graz emim ribbons are extremely well done and are made the way the EMIM-membranes should have been from the start.
The sound from them totally transforms the speaker to a whole different level of HiFi.
I recommend them full heartedly!

I just browsed through ebay and saw that there actually are 1-2 that are flat and all the rest have twisted bars.

So, be careful when buying used ones on sale!!!
 
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Thanks for the info.

Ownership of these old damn flagship Infinities is like maintaining a vintage Italian exotic car.
 
Yes, the Graz emim ribbons are extremely well done and are made the way the EMIM-membranes should have been from the start.
The sound from them totally transforms the sound to a whole different level of HiFi.
I recommend them full heartedly!

If anyone plans on keeping there Emim Infinitys for a long time the Graz diaphragms are the way to go.

Btw all my emims plus the extras I have are perfectly flat. The original ribbons looked very good and played fine and I still have them. I'm saving them in case I come across another pair of infinitys that are toast.

I've been lurking on this Infinity forum for a few years. I am by no means an expert but have never heard anyone talk about bent up emim frames. Just the flaking neo magnet problem, broken traces in the ribbons and melted ribbons from playing them too hard. Not bad for 30+ year old speakers.
 
I think it was just a bad batch they got from their jobbers, hopefully a small lot, the assemblers should have noticed that tho,

Slim, I have the feeling that any Infinity using emims is going to be around a LONG LONG time :) Just go out and listen to the modern 5 didgit stuff out there and most still don't compete.
 
Slim, I have the feeling that any Infinity using emims is going to be around a LONG LONG time :) Just go out and listen to the modern 5 didgit stuff out there and most still don't compete.

I have to agree. I listen to a lot of pricey high-end stuff in my audio club meetings, and I still haven't heard anything I prefer to my RSIIb's.
 
I think it was just a bad batch they got from their jobbers, hopefully a small lot, the assemblers should have noticed that tho,

Slim, I have the feeling that any Infinity using emims is going to be around a LONG LONG time :) Just go out and listen to the modern 5 didgit stuff out there and most still don't compete.

Yeah, maybe they were backordering and counted on that the problem would not emerge until complaining was "too late".
Who knows!:scratch2:

Scintilla's working out?
 
Here is a newly adjusted and realigned front part with Kapton protection strips.

I have done 2 sets of EMIM now. 12 to go...


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Jarre, nice job look like new, you gonna put the cloth back in apon reassembly?

I LOVE my Scintilla's, I finally got the Diva's perking, had to tri-amp them tho, but the RS4.5's still out image them.
 
Yeah, I am putting the damping cloth back on the rear magnet assembly.

Sad, but I can't find any use for the old EMIM membranes and I don't want to to fool anyone thinking that they are good to use.
They work and sound but not the intended way.
 
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