History of IMF

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

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.


John Hayes

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