IMF (later: TDL) anybody using them? - here, Compact II

[hatehifi]

After the Belgium MiniMeet my ears were still remembering Mikael's Rogers LS3/5a with my Almarro A205A MkII amp. Lovely, So, as there is no chance for me to buy a pair I did some thinking (yes, happens on rare occasions )... I've got Christian Schulz' deCapo amps coming soon (and already have some massive stands with another pair in my sights), so why not go for it?! I confess, I've never heard these, the smallest IMFs but, I've always loved the IMF sound. Somebody had some great ears. Maybe with some x-over rolling or super tweeter I'll get 'close' to that LS3/5a sound...

Just plucked these off ePay:

(pic later... Firefox says 'no' right now)

Audax HD17B25J woofer and a Kef T27 SP1032 which I'm sure will work. I know the T27 well (had the KEF107R for a while and sold KEF like hotcakes back 'then'), and I'm sure some must lust for that Audax too - no funky grey surround to crumble either  !

Cheers!

http://www.marklev.com/IMF/CompactII/index.html

[hatehifi]

I'm waiting for the okay for 'my' speaker photo but here they are as found in the web



photo via cgi.ebay.com

[mosin]

There is an interesting story that surrounds the IMF speaker. It was a controversial line, to say the least. IMF stands for Irving M. Fried, known as Bud.

Here's a letter from one of those involved. (I found it on the Net awhile back.)


Dear Whoever,

I read with interest your site describing the background of IMF. I am the sole survivor of the three Directors of the Company. I first met John when I was a Director of an electronics company in Amersham, Buckinghamshire. We jointly designed a record turntable made of perspex (Plexiglas). John designed the tone arm and we won some design awards. It was belt driven and servo controlled by a separate electronic control module. At that time John was interested in producing a transmission in line speaker and had made one for Irvine Freed to demonstrate a wide range Decca cartridge at the New York Hi fi show. After the show, Bud said he had taken a number of orders for this speaker and John and I got together and started to manufacture the original professional monitor. Of course, Bud, had a called it the IMF, and therefore, perhaps mistakenly we registered IMF and formed and IMF company. The Directors being myself, John Wright and David Brown who was a partner of mine already. At no time did Bud Freed have any input on the designs. We sold him speakers and he was the US Distributor until he made some cheap speakers and called them IMF. We pointed out that we had the rights to the registered name and that by making a cheap, poor quality speaker would cause damage to the reputation. He refused to back down and it ended up as a lawsuit which we won. Bud was never involved with the British IMF Company and only visited a couple of times. He never forgave us for blemishing his reputation which he had promoted in the USA as an entrepreneur and hi fi fanatic. After the lawsuit we formed our own American Company and distributed ourselves throughout the USA.

For a time we sub contracted cabinet manufacturing and bought in drive units from KEF, but decided it would be preferable to make our own drivers and cabinets. We bought a cabinet factory near Oxford and formed an alliance with Elac to make the drive units. We formed a company jointly owned by IMF and Elac (TDL). The most significant was the large base unit which had a thick tapered styrene cone with a plastic coating, this produced a rigid piston action and was extremely light without any cone break up and produced an excellent fast response at low frequencies. We were one of the first companies to use Ferro fluid in tweeters reducing ringing and giving good heat dissipation. John and I worked closely together on new designs. My idea was to produce a smaller transmission line speaker but size limited the length of the folded line, which meant the port went out of phase too early. The answer was to fit a low resonance base unit where the port would normally be. The cross over system had a separate filter for the lower base unit and maintained and in-phase response to around 18 Hz. Internal air pressure prevented the cones being over-loaded with high power low frequency pulses. The super compact was effectively a tuned port, only I considered a flat damped panel to be an advantage.

John always wanted the finest performance and was fanatical regarding quality. He spent endless hours producing demonstration tapes for the hi fi shows that we attended. His articles that appeared in many journals reflected both his dedication and knowledge.

During this period, Prof. Peter Felgett then head of Cybernetics at Reading University, developed the idea of true surround sound and Michael Gurzon developed the mathematical formulas by which a microphone with 4 capsules in a tetra-hedral array could receive sounds from all directions and encode the signals so that they could be decoded producing side to side, front to back and height information and low frequencies (omni). We formed a team, myself, John Wright, David Brown, Prof. Felgett and Michael Gurzon. I remember spending many hours in the anacoic chamber working on the surround sound microphone. BTG then known as the National Research Development Corporation paid for the patents and ultimately, the system was perfected. Our timing was bad as the collapse of Quadraphonic made people wary of Ambisonics. Furthermore, the bureaucracy of BTG made it extremely difficult to move forward.

To promote ambersonics we at IMF formed a recording company and I and a sound engineer travelled to the States and recorded at numerous venues. The records won acclaim for the best stereo without decoding and played in surround were spectacular. We recorded Dixieland, Blue Grass and Big Band. In the UK I assisted John in recording at numerous venues including much Classical, and I still have many of the tapes. Nimbus records in Monmouth transcribed our tapes to disks and using normal equipment and decoders manufactured by IMF produced the most remarkable realism. I travelled to the States and our records were played on PBS (the US public broadcast stations) and various venues had decoders and produced the surround sound off air, with generous praise from all concerned. Meanwhile, I had formed an alliance with Dolby, but the management at BTG insisted on dealing with Ray Dolby and their demands of management, if he became involved, drove him away and he went on to develop his surround systems. Sadly, Michael Gurzon died of an attack of asthma but his work was a milestone in understanding the mathematics of surround sound.

Meanwhile, IMF continued with a wider variety of speakers. We designed a speaker for surround sound with a balanced polar diagram, this is the MCR2A. this was designed to have a reasonably narrow polar diagram so that it would integrate effectively and maintained phase when used in fours for surround or in eights if height information was to be included.

Due to my personal connections at Buckingham Palace, I persuaded those with influence to get the BBC to record, with our help, the marriage of Diana and Charles at St Paul's Cathedral. The BBC after some persuasion agreed and the BBC installed surround sound microphones both inside St Paul's and outside to capture the crowds cheering. I still have the BBC Master tapes. The BBC asked BTG to pay for the cable, (everything else was free) and BTG said they wouldn't pay the £500.00 expense. After some argument they paid. I was invited to Kensington Palace to play the tapes for the Royal's approval prior to their release. I remember we installed four studio monitors and managed to wake up the Duke and Duchess of Kent by demonstrating at what I thought was a reasonable level.

The world moved on and despite Denon, (Nipon Columbia) taking out a licence, I can say that BTG were a hindrance as, having paid for 115 patents their bureaucratic Civil Service mentality tried to exclude our help and co-operation and put on demonstrations with no technical ability, speakers wired the wrong way round etc. etc.

The world economic situation hit our cash flow and David Brown resigned and eventually went to the States to retire. He sadly died of cancer several years ago. I had worked with David Brown when he was Sales Manager and I was Works Director of Dawe Instruments a subsidiary of Lucas CAV. We came to the conclusion that we should terminate production and move in other directions.

We originally sub contracted drivers to the Elac company and subsequently formed a joint company called TDL owned by both Elac and IMF.

John decided that in co-operation with the existing TDL Company and with the support of Elac would manufacture transmission line speakers under the TDL label. Eventually a TDL company became independent and John continued but his health was failing. He also died of cancer a few years ago and the TDL name lived on for a while. But, in my opinion, without the entrepreneurial spirit and a large investment, TDL was not going to survive.

As you will no doubt see, I am disposing of much of the hi fi equipment on Ebay, with the help of one of my engineers. Obviously the history is more complicated than I have said, but I still believe that we made some of the finest speakers ever produced. I have the most fond memories of John locked in the anacoic chamber and the hours we spent listening and tweaking to produce the desired effect. On a final note I remember swapping a pair of professional monitors with Dr. Nacamichi for one of his model 1000 cassette decks and visiting Japan and spending several days with Nipon Columbia and Denon looking at their latest developments and sitting in their listening room with a pair of our monitors and a pair of their latest speakers. After some time I was asked what I thought. To be polite I said there speakers, which had been designed using laser technology, were interesting and had a good response. The President looked at me, smiled and said, "Why are you speakers so good and ours are bloody awful". Those were the days.

Bud Freed was never a Director or shareholder of IMF Electronics. IMF electronics were the only company manufacturing the transmission line speakers. The name IMF was adopted because Bud Freed had demonstrated the first prototype speakers at the New York hi fi show, and because of the publicity and the fact that he had used his name on the then unnamed speakers, we stuck with the name which was a mistake on our part. It was never his company. After our lawsuit he called his speakers Freed.

I am just about to dispose of two integrated, high quality lab designed amplifiers, with built in UHJ decoders. There are four 100 watt outputs plus an additional output for omni directional base to feed a sub woofer.

They have the usual inputs and controls with solid state switching for mono to all outputs for surround balancing, side to side and front to back balance, UHJ decode, and stereo decode with variable width to wrap-round stereo signals. They are standard rack size, anodised black front panel.

Signed

John Hayes

[fergs1]

I have a pair of super compacts, the second pair i have bought for $5 in an  opp shop. the first pair I sold at great profit the second pair I bought about a year ago are a bit scrappy but sound fine. Personally I prefer a more dynamic speaker. cheers fergs

[hatehifi]

Thanks for the letter. I too have been searching the web but never saw that.

I am a bit surprised about the ELAC/KEF because I don't think that that is a KEF woofer. I shall open one and see what I find (likely nothing!). I read that they did 'modify' their chassis but reading this letter, well, I am confused or, rather, am alarmed at what is on the net for false statements. What'd you say, "don't believe everything you read?"  

My old American buddy Larry W. (used to be techncian for Audio Intl - Klipsch, Infinity, Decca, etc., German importer & later Technical Chief of Nachamichi Germany), said, "John, listen to some of those Freed speakers, amazing!" Well, I did hear some IMFs (never their largest but 2nd, the RSPM IV    18Hz!). I just read in one of the studio recording forums that a lot of jazz was recorded in Holland using my Compact IIs and that they are 'better' than the NS100 (a steadfast 2-way monitor), that you can use them for mastering and you'll end up with a 'better' recording's playback on the 100's than had you used the NS100.

I think one of the TNT-audio.com 'oldies' uses IMF (or one of the kits...). It really is a shame that they went wayside. Germany has produced a lot of TML (transmission line) speakers but I have never heard one with such 'reality' as the IMF. BTW, this goes for any other speaker, including horns, except a rare subwoofer and maybe, of course, with professional DSP management.

Looking forward to hearing 30Hz (yes, I believe them) from such a small box. Oh well, they'll keep me off the streets for a while...

I have a pair of super compacts, the second pair i have bought for $5 in an  opp shop. the first pair I sold at great profit the second pair I bought about a year ago are a bit scrappy but sound fine. Personally I prefer a more dynamic speaker. cheers fergs

Those are the 3-way compacts? I think driving them (all IMFs) is a challenge in itself. I'll report. Wish I had paid $5 for mine!

[mosin]

... I am confused or, rather, am alarmed at what is on the net for false statements. What'd you say, "don't believe everything you read?"   ...

I believe a lot of what you have read may have been spread by Fried himself. It appears that he built a persona on the inventiveness of others, and when he became too greedy they gave him the boot. Yet to this day, most people associate the name of the company, and the ideas its true originators developed, with him. That is a shame, in my opinion.

[ejfud]

I'm currently running a pair of TLS50's in my space and really enjoy them.

[jloveys]

Remember Gainsbourg turntable ? an IMF ! 

http://www.lencoheaven.net/forum/index.php?topic=5177.0

[mosin]

That's a very interesting and advanced turntable for its time. Bear in mind that IMF was founded in 1968, according to the most believable accounts. If the letter is to be believed, the turntable was done even earlier than that. It seems by the look of it that they were serious trendsetters because the concept looks quite modern in comparison to other turntables of the day.

[hatehifi]

I believe a lot of what you have read may have been spread by Fried himself. It appears that he built a persona on the inventiveness of others, and when he became too greedy they gave him the boot. Yet to this day, most people associate the name of the company, and the ideas its true originators developed, with him. That is a shame, in my opinion.

Right you are! I was going to correct my spelling of Fried today after some research. It dawned upon me that the name was Fried and not Freed as I wrote, read... Yup, had Fried pegged up there with Kellogs, Thiel & co. - what PR, and as you say, what a shame.

I'm currently running a pair of TLS50's in my space and really enjoy them.

Heard them several times and yes, do like. Last time I did I spent close to two hours setting them up in a very tricky large and 'full' open space loft and had to go on two walls. Marked floor with tape but HF came home and had hubby put them back where they looked nicer. 

Remember Gainsbourg turntable ? an IMF ! 

http://www.lencoheaven.net/forum/index.php?topic=5177.0

I sure do!

[Chopsaw]

I have a pair of IMF Pro monitor IIIs in my main system and a pair of TDL Studio 4s in my upstairs system. I also have a pair of TLS 50s waiting downstairs to be collected by the new owner.

[hatehifi]

Burning in my 'improved' Almarro A205A MkII the doorbell rang and my ePay shipment from Holland arrived   . As I already had the 'sound' of my amp with the 16 Ohm tap on into the 16 Phm Zu Superfly, well, just needed to hook them up (have screw terminals and my speaker cable, Zu Libtec has cable shoes) to hear what they do or don't do. Immediately I could 'hear' how hungry these guys are! So, instead of 7-8 o'clock I needed, like with the Rogers LS3/5a, to turn up to 10-11 o'clock (clipping starts at ~1 o'clock). They need power to sing.

What did I hear? The difference is really very little! I suppose I could sum it up with, "a shift from bottom to top." Tonally, the IMFs obviously don't go down to 30Hz (likely -6dB here) but do not 'lack' in the bass registers. The highs are quite revealing and not at all 'hot'. If you so will, they sound a tad 'clearer' than the Zu. I'm listening to Pat Matheny's Letter from Home and the bass just kicked in and really startled me. Here is no 'lack' of bass and actually, maybe they go lower than the LS3/5a. Pat's guitar is just 'there' like it should be. There are more artifacts to the recording than with my Zu. The whistle sounds like a whistle. After 2 hours' play they are starting to open up.

The grill cloths are attractive but do 'eat' too much signal for my taste.

As you can see, one tweeter was pushed in and whenever this happened, unfortunately it was not repaired (suction or tape, e.g.) immediately and has 'stuck' to how you see. I tried tape and even some oral suction but no chance. I am actually not sure that I can really hear it, like maybe 5% 'less'... Anybody have any ideas? I do not think I'll try to find a replacement as I assume that IMF paired them. The serial numbers are the same. I am also not sure that they are stock (I'm guessing T27 Kef but correct me if anybody knows better) and if I did one membrane, I'd have to do both (age). Any tips?

I can easily hear why these are considered studio [mini] monitors as, to repeat, they are very revealing. Piano, sounds real though [much] smaller than with the Zu. I received my Pioneer A6 integrated today as well so maybe I try it (and also try my Ampino) on them tomorrow. Whatever, on substantial stands, I think I have a poor man's LS3/5a here. Will do a reality check next time I visit Jean...

I lived with the Celestion SL600 for many many years and these are not them. They do remind me of the LS3/5a and I don't remember hearing any other mini monitor as good as these. The SL600 were a different breed and I don't think they ever made it into a mixing room while these IMFs certainly did.

I can't hear that any crossover part is broken or failing. They sound new in this respect but if anybody wants to suggest for me to upgrade, I'll consider the proposition. However, as an American I may stick by my guns and decide, "if it ain't broke, don't fix it." Man! Those finger cymbals really 'shine' here!

Cheers!

P.S.: Am I in a hurry to get back to my Zu? No.   Help! I need a larger place, more listening rooms!

[autobayer]

Nice, John.
I must say, I never liked the big IMFs - too much of everything for me. And ugly 
But those I like from the pictures, I am sure, they sound good.
And I want a pair and more rooms and aaaahhhh.
Good shot!
C

[hatehifi]

Nice, John.
I must say, I never liked the big IMFs - too much of everything for me. And ugly 
But those I like from the pictures, I am sure, they sound good.
And I want a pair and more rooms and aaaahhhh.
Good shot!
C

I know what you mean with the large IMFs but I remember one (IMF Ref IV?) with an early Mark Levinson combination (before he sold) and I almost wet my pants but you are right, pairing with electronics seems to be a major task, should not be taken lightly.

"...And I want a pair and more rooms and aaaahhhh." 

Maybe we should start a LH PR/ad agency, machine shop, listening room resort? You know, like a time-sharing model!!!!  (of course with medical attention) Old folks home for the retired HiFi folk!

[Wout]

Nice score John!

and even some oral suction but no chance.

Sorry, are there any photo's of this event?