IMF owners thread!

Hello IMF fans!

I just restored these CM2 (Compact Monitor 2) loudspeakers:

IMF CM2 by antennaguru uda, on Flickr

I refinished the cabinets to overcome some wear and tear, while trying very hard to keep them as close to original as possible. I bought a replacement capacitor set from Falcon in the UK and installed/upgraded the crossovers with the new capacitors, and inverted the woofers 180 degrees to mitigate potential suspension sag (though none was evident as such) during re-installation. I also replaced the rotten front panel cosmetic foam that covers the resistive slot openings with fresh open pore filter foam. I was happy to find the internal foam in excellent condition. They sound as good as I had expected too.
Nice job. Will get next week also a CM2 project to handel. Did the new capacitors set and foam made the whole peformance better (highs, low, mids, imaging). What is your impression
 
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Any chance you could take a better picture straight on and minimal glare? Also give me measurements?

I have been searching the Bay for some originals to come up for sale, but no luck. I am going to have a trophy and engraving shop down the street make a pair for me.

Thanks,
Dogwan

Could also get a 3Dscan of an existing one and then have it 3D printed.
 
Hi Everyone, I have a question for TLS50 / 50 MK II, and Super Compact Monitor I / II / III owners. Can you advise which woofers and cone midranges your specific speakers have inside? I know the mids to be hard to remove for inspection so a pic can almost be just as helpful.

Reason I’m asking is to try to build a rough database or experiential data pool of drivers used to aid in identification and replacement if possible.

For the TLS50, I’m expecting a KEF B200 type or IMF / ELAC 8” woofer, for the Mk II version mostly the ELAC (8/22, 8/24 or 8/26). For the SCM, probably the same types, just different spec number. All should be bextrene type drivers.
 
Sadly that site has fallen into a state of disrepair as it's no longer maintained. It used to have a lot more information on it but it has gradually disappeared bit by bit.

I have offered to take it over many times and make it a much more comprehensive site, but it's owner just wants to do nothing with it and instead plays on the "discord" site, something that I'll have nothing to do with.
 
Hi, I know the tls 50 mk I came with mostly Kef b 200 Sp1014 and some peerless woofer too (# ?), samething for Als 40 mk I but many with Peerless woofer with another Peerless with different magnet very well damped round frame with clamps to hold both woofers, some woofer came with white surround with frame like the old B&W, mid is EMI 4" like in the old Decca speakers in all the Mk 1 serie no foam,no real rubber surround but look like very thin mold black film (strech),tweeter Peerless with wire outside across the middle with felt, later Peerless with diagonal line, woofer,mid,tweeter all 8 ohm, super tweeter's they say microphone encapsulated install on a faceplate ,see no magnet minimum 16 ohm probably more? Even the tls 50 mk II use the same super tweeter's.tls 50 mkII came with woofer B200 Sp1022 and later Sp1039 ,later Elac 8/30 and later 8/30 with rib on the cone .Audax mid,Audax tweeter ,Peerless tweeter ,later Elac mid, Elac tweeter.same microphone STW or maybe Coles STW latest model. Maybe the time IMF use the Peerless woofer happen at the time KEF have a big fire and change a bit the mold casting shape of the B200 Sp1014 frame? Or not. Before the Tls 50 mk I was the old Studio.
 
Interesting to know how a freq curve from 20 to 20.000hz looks like for the Compact II en the Compact II monitor (CM2). Measurment done with Mathaudio Room EQ.
Compact II
c1BTn55.png

CM2
8C4QAmq.png


When using the Bypass mode I notice that the Correction made on the CM2 is way less than with the Compact II. You can also see that the Highs are more stable from the CM2's. The CM2 has almost from design a flat curve. Also Dynamic headroom of the CM2 looks much better.
 
@ mech986 I've got a pair of recently purchased TLS50 MKII's and I have to pull one of the woofers to find out what it is so I can find a replacement.
I will see if I can check the mid for you too for your "rough database"
I'll post my findings within the next few days.
 
One pair of my TLS50mkII has the later KEF B200 SP1039 as used in the KEF Reference 104/104aB speakers. The midrange is the ELAC 43M/101 with the white cardboard cylindrical gasket at the outer circumference of the surround. The surround has the typical stiffened and extensively dimpled degradation literally into a stiff crumbly mess.
 
Could also get a 3Dscan of an existing one and then have it 3D printed.

I'm looking into doing this with my son's 3D printer. He said he could probably print out any number of them as needed. What would people need, the "IMF Electronics" version, or the early "IMF" only type?

Sadly that site has fallen into a state of disrepair as it's no longer maintained. It used to have a lot more information on it but it has gradually disappeared bit by bit.
I have offered to take it over many times and make it a much more comprehensive site, but it's owner just wants to do nothing with it and instead plays on the "discord" site, something that I'll have nothing to do with.

That's very sad and I know the site has not been updated for some time. Also, the letters/email regarding IMF and Bud Fried (who distributed them early on in the USA but had NO input on the design of IMF speakers) need to be preserved elsewhere with attribution. In fact, IMO, much of the info and data should be downloaded and saved for another more organized site if the owner will not manage them properly.
 
I'm looking into doing this with my son's 3D printer. He said he could probably print out any number of them as needed. What would people need, the "IMF Electronics" version, or the early "IMF" only type?



That's very sad and I know the site has not been updated for some time. Also, the letters/email regarding IMF and Bud Fried (who distributed them early on in the USA but had NO input on the design of IMF speakers) need to be preserved elsewhere with attribution. In fact, IMO, much of the info and data should be downloaded and saved for another more organized site if the owner will not manage them properly.

In order for one to view the missing links on the IMF website one has to pay embee.duckdns.org for it's use.
 
who would that actually be ? as I've never seen anything about payment for advanced features displayed on that site.

I was able to find their site which required payment to view the missing Fried and IMF pdf files.
This is one reason why Stephan has let the IMF website go.
 
Hello


New to these forums, but not new to IMFs.

I have a pair of IMF CM2 and a pair of CM2A. and also had a set of TSL80Mk2 for quite a while.


The CM2s I have had seen new, and the CM2As bought 2nd hand 15 years ago. (I’m guessing they are both about the same age, manufactured 1980-81, (both with the foam grills that have now fallen apart...but made some nice new cloth framed ones that use the orignal velcro holders)


As far as I can tell the speakers are identical apart from the CM2 being ported?


Ok, here is my problem. Even though when I bought the cm2A I was satisfied with the sound and a full frequency sweep revealed that both tweeters and woofers were working correctly, I have now identified a problem with them.



They are currently being used as surround speakers in my home theatre. I am running a Denon receiver which runs the Audyssey microphone calibration set up. In looking at the equalisation curve for the cm2A it was showing that they are flat up to 2 kHz , but needed 6dB(that the maximum Audyssey can give) of boost in the 4, 8 and 16k bands, whereas the CM2s were relatively flat across the spectrum. Swapping speakers about the room and indeed using the cm2A by themselves as mainspeakers showed that they were consistently down by 6 dB above 2 kHz, possibly more given that is the max boost audyssey adds.

Were the tweeters not working? Well testing with high frequency tones revealed there were(and physically blocking the tweeter directly did have an effect on the output-so it wasn’t just high frequency getting reproduced by the woofer), just quite a bit down compared to the CM2s. Interestingly Audyssey was showing that within the pairs each speaker was within 1 dB of being identical to the other.


Interestingly I hadn’t use either pair as my main speakers for over 20 years and was surprised to see how good they still sounded when driven hard when I was comparing their responses..


Questions:

1. Was that the way they were made(the CM2A), or have they deteriorated.(unlikely they would have been 6 dB in the top end at the time?)

2. My understanding of the audax tw1500F tweeters is they work or they don’t work, their output shouldn’t decrease with time?

3. Are we looking at problems in the cross overs of the CM2As……..I suppose I could answer this for myself if I opened both speakers up and played tones through the respective woofers and tweeters bypassing the crossovers.

4. Are the crossovers different for the two types of speaker, or perhaps made at a time when one supplied component was not up to it?


At the moment, given Audyssey has spectrally taken care of the problem in my home theatre setup, it perhaps doesn’t matter, but would still like to get on the problem if we decide to do something else with the cm2A


Suggestions on where to go from here. (apologise if this is covered somewhere in the 84 pages so far)


Thanks


Sac

Just an update on this issue. I pulled the tweeters from the cabinets, drove them directly without the crossovers and they sounded very scratchy with 6 and 10 kHz tones with a one volt AC input, should only be 1/8 watt. Further research has suggested that this problem could be due to the ferro fluid drying up and making it hard for the coil to move. As carefully as I could I removed the coil from one of the magnets to investigate whether dried up fluid was a possibility. The coil showed no sign of any fluid at all, but unfortunately some of the coil wiring was separating and basically it looks cactus as well as a bit of a burnt smell. I did the other speaker and when attempting to prise the magnet away from the cover plate the coil just stayed inside the magnet and separated itself from the dome, the second coil had enough ferro fluid in there to get my fingers dirty though.

So I need two new replacement tw1500f replacements! One thing I did discover that may be good for someone else that goes down this route is that the wire dental flosses I have will fit neatly into the coil magnet gap, I dipped the wires in to some propanol and was able to thoroughly clean out the gap.......sounds easier than the masking tape method some have listed.

Buying originals second hand?, may not be long until they have the ferro problem and there is the issue that trying to pull the coil from the magnet may end up going pear shape.

I see that Falcon Acoustics sell replacement non ferro ones in the 12 x 8 size, but offer the same tweeter? considerably cheaper in the 12 x 9 size.

Has anyone got any info on how the new non ferro fluid ones compare?

Incidentally, the tweeters had 1984 stamped on them, so they are at least four years older than those in the CM2s I have(purchased 1980) which are not displaying any problems at all.
 
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Then who is paying to keep that site alive. There is so much info that could be there but just isn't. If only it was taken over by someone that actually gives a damm.

I am not sure.
You can ask Stephan on his new site Discord.

The missing pdf files are really missing since I can't find them anywhere on the internet.
 
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