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P.G.A.H. VOIGT: A Great Audio Inventor

Discussion in 'classic' started by eguth, Apr 8, 2010.

  1. eguth

    eguth pfm Member

    MEMOIRS OF A DIY HI FI NUT - Part XVIII

    PAUL (P.G.A.H.) VOIGT: A Great Audio Inventor


    By Eric Stubbes​

    I​
    Introduction

    This Memoir is part autobiographical and part biographical. Why should I stray into biography? Wait and I will tell you.

    I never met Voigt. I had never even heard of him until I was aged 30.

    I moved from the English midlands to south London in 1981- a few miles (at most) from where Voigt lived, was educated, worked and invented and not all that far from the Lowther factory. I had a listen to one of his inventions in my early youth. That left a strong impression.

    My justification for writing about Voigt, biographically, is that I have uncovered information that, although known by a limited few has not, to my knowledge, been previously published.

    Enough preliminaries.

    I divide this Memoir into sections. You will occasionally see numbers after sentences. These numbers refer to footnotes to be found at the end of the final section along with acknowledgements and permissions.


    II​
    My first experience of a Voigt invention was in the early 1950s. I must have been around the age of 11-13. A friend's father, who was a skilled amateur cabinet maker, built a Lowther horn into a piece of furniture he had constructed. I have no idea which driver or horn. The horn had a small mouth about 2 feet by 2 feet square, as I remember it. The turntable was an early model CONNOISSEUR– one of the direct drive rumble machines- also built into the cabinet. No rumble was audible. I imagine that this was because the speaker did not go low enough. I knew nothing about hi fi. These were the days of mono. The speaker was driven by a valve preamp and amp.

    The sound from that horn was clear, direct and natural. It did not go down to the low frequencies. But it sounded wonderful to me- indeed significantly better than I had ever heard from a hi fi. [It was not until decades later in my hi fi journey that I became dead against ‘bass light’ systems and systems that were unable to reproduce really low frequencies].

    I did not know that Voigt designed the speaker- though the word ‘Lowther’ was mentioned. I tucked the word ‘Lowther’ into the back of my mind. It stayed there until the 1970s, when it migrated to the front at the National Sound Archives in Exhibition Rd. where I regularly listened to Lowther ‘Acoustas’ fitted with PM6c drivers. I was amazed at the stereo imagery they produced- even with a very long run of speaker cable and a ropy transistor amp.

    Now fast forward to the early years of the 21st century. While strolling through some back streets I unexpectedly came upon a hi fi dealer’s showroom. I went in. I saw large and beautiful wood horns, folded and of round section; true horns. I asked for a demo. The horns were called ‘CARFRAE’ fitted with the latest Lowther drivers (DX4) modified with a wood phase plug. The maker quoted a response of 32Hz to 22KHz (no dB rollofs ever given for Lowther drivers!). They cost £18K then. Break open my piggy bank. These were fired up with a pair of AUDION single ended valve monobloks. The source was CD. I insisted on hearing a big band so that I would not be seduced by the reproduction of only one or two instruments; relatively easy to do so that they sound ‘live’.

    I was only able to listen for about 10 minutes but left certain that this was the finest system I have ever heard. However, I was not impressed with the deep bass and when the music stopped there was the most appalling loud hum. I couldn’t live with this. Hum masks low level detail; even a little hum. Hum always upsets me. But I left convinced that true horns are the best speakers. Here was a tractrix horn designed by Voigt and fitted with a loudspeaker driver also designed by him some 70 years previously- and improved in details only. Yet it reproduced recorded music better than any other in my opinion. The most striking improvement is in delivery of the higher frequencies. This twin cone cone was patented by him in the 1930s, the tractrix horn in 1927.

    I will pause here. I am especially interested in comments from anyone who met Voigt.
    ___________________________________________________
     
  2. pure sound

    pure sound Trade: manufacturer/distributor

  3. addict

    addict Registered User

    I was listening to a pair of Voight corner horns yesterday. Probably one of the best speakers I have ever heard.
     
  4. smithy

    smithy pfm Member

    There was an article I have got somewhere in an old HIFI mag about some wooden Voight tractrix horns found in a dance hall in Selsdon (Croydon area, not far from Norwood)I will try and dig it out.
     
  5. eguth

    eguth pfm Member

    smithy

    If you can hold on till the end of my Memoir I give the reference for the article you seek in a footnote. This may save you hours- if not days- of rumaging around the basement with the attendent risk of backstrain.

    If you really can't wait until then say so and I will bring along the reference to you when I see you next.
     
  6. eguth

    eguth pfm Member

    MEMOIRS OF A DIY HI FI NUT - Part XVIII​
    P.G.A.H. VOIGT: A Great Audio Inventor​

    III
    The Basset

    I turn the clock back, now, to 1969- more than 30 years before my CARFRAE demo. A Hi Fi News article about a new bass speaker design was published, written by Trevor Attewell.

    I was living in the midlands and had experimented, unsuccessfully, with a large and extraordinarily heavy ‘City of Birmingham Corporation’ concrete drainpipe. This was delivered to my flat by two hefty working men whose exotic vocabulary during the delivery I shall not repeat. I attempted to use this municipal item for a purpose other than what it was intended for: a 15” woofer enclosure. I somehow managed to live on after that experiment without a hernia.

    The Basset article (Hi Fi News, April 1969) set my enthusiasm alight to build a deep bass cabinet lighter in weight (hopefully). I hoped that this would enable me to continue my hernia-free life.

    This enclosure was designed primarily to correctly play deep organ pipe notes that most other speakers cannot come anywhere near doing. It was splendid for my purposes because it can serve as a large equipment table. It is the size of a human coffin (for a six foot man), inexpensive and easy to construct. Over the years since I built it I have modified it in so many ways- not all of them successful. The basic design is sound and I am still using it in its original cabinet more than 40 years later.

    The Basset is a version of Voigt’s original design; the quarter wave pipe. I built only one Basset (one is enough) and combined the L&R channel signals into mono bass. The first Attewell Basset sported a passive crossover. This never worked very well. Bits of bass floated into the midrange and caused various problems. I eventually scrapped the (by then extensively modified) passive crossover and bought a Falcon Acoustics active crossover kit with a separate power supply to roll the bass off; a bandpass filter starting to roll off at 50 Hz, 18dB. This worked well and still does. Caruso sings bass notes no longer.

    The Basset is, of course, far from perfect: but listeners have commented that it is extremely well integrated with my other speakers- so well that it is ‘seamless’. This is hard to achieve with some commercial subwoofers. The Basset goes down flat to 22Hz before rolling off. I have felt it produce 16Hz. The beauty of the Basset is that you get low bass performance in a (reasonably sized?) cabinet. It is not very light in weight because I have used 2 x 12” drivers with extra large magnets fitted and have put reinforced concrete under part of the top panel. Not many realise that they are seeing and hearing a subwoofer. If you were listening to music in an undertaker’s parlour would you think that some of it is coming from a coffin? Voigt’s quarter wave pipe fills the room with sound in a way that horns seem to do.
    I was a keen Hi Fi News reader in those days. I remember Editor Donald Aldous once asking me my opinion of Hi Fi News. I told him “I have no criticisms”. The conversation went something like this:

    He: ‘None at all?!’
    Me: ‘None’.

    He seemed both pleased and slightly ruffled. (I expect that most hi fi magazine editors receive more than their fair share of gripes).

    I thought that I would like to see a copy of the original Voigt quarter wave design, but neither Trevor Attewell nor anyone else I had come across had published it. So I went down to the Patent Office- then in Chancery Lane- and hunted up the patent. To do this I had to search index cards stored in long, small, narrow oak drawers. Eventually I found it. It is Patent No.447749 filed in 1934 as ‘Improvements in Means for Converting Electrical Energy into Sound’. Voigt held 32 patents. I ordered the quarter wave pipe patent papers. I recall the thrill when I saw the drawings and description and noted that only in minor details does the Basset differ from the original. The basic design places a loudspeaker 1/3 the way along a tapered pipe/horn to produce good bass. Remember; these were the days when bass rolled off below 80Hz on a good speaker, and going down to 40Hz was unheard of.


    [​IMG]_S341083 by Round Person, on Flickr


    [​IMG]_S381089 by Round Person, on Flickr


    [​IMG]_S351085 by Round Person, on Flickr



    [​IMG]_S391093 by Round Person
     
  7. donmusic

    donmusic Let's talk about music and DIY

  8. eguth

    eguth pfm Member

    I, too, love the GOOD old stuff, and the GOOD new stuff: what I don’t love is the BAD old stuff and the BAD new stuff!
     
  9. eguth

    eguth pfm Member

    MEMOIRS OF A DIY HI FI NUT - Part XVIII
    P.G.A.H. VOIGT: A Great Audio Inventor​

    IV
    Home​


    Voigt, the son of German immigrants to England, was born and bred here and had every claim to being as English as anyone else, moreover, since his parents were naturalised British citizens. Nevertheless his parentage was the cause of discrimination against him- as we shall see. To his credit, he never sought to disguise his parent’s origin. This would have been easy to do by changing his name. He carried around his ancestry with his name, his first and middle names being: ‘Paul Gustavus Adolphus Helmut’. The ‘us’ suffixes after the German first names were Romanized forms of German names. This practice was fashionable in Germany around the turn of the 20th century at the time Voigt was born.

    The parents came from Elberfeld in Wuppertal, Germany: Emmy Peters (1871-1974) and Paul G. A. (Sr.) (1867-1937). Emmy was from an important family who operated a very large fabrication facility that produced cloth and hats. Paul Sr. and Emmy married in 1900 and immediately moved to London. Their application for British Citizenship was accepted. Paul Sr. joined/established the Peters-Voigt company in London as a branch of the German company. The object was to develop UK hat sales.16

    Paul Jr. was born on December 9, 1901. The photo that follows was taken circa 1902 (born in 1901 but he sits up, so he is at least 6 months old according to child care expert B.G. Rasmussen).

    [​IMG]1st PGAH alone 1 by Round Person, on Flickr


    Paul Jr. had 3 siblings; Harold (1905-1911), Hilmar (1906-1978) and Gracie (1907-1923). Sadly, Harold died young of scarlet fever and Gracie of appendicitis. The family photo below was taken in 1907. From left to right: Paul Jr., Emmy, Gracie, Paul Sr., Hilmar, Harold. Unfortunately, the dog shall have to remain nameless.

    [​IMG]1st PGAH w family 1 by Round Person, on Flickr

    The early, formative, years were spent living in the family home in Forest Hill, southeast London.

    Some get their thrills and spills from driving fast cars or rollercoaster rides: me? No, thank you. My thrill comes from visiting the places where famous and eminent people I admire have lived and worked.

    My interest in and respect for Voigt led me, on 16 May 1994, to get on my trusty 30 year old hand- built bicycle to see whether the Voigt family home was still there. I had the address and the name of the house.

    I have been a keen cyclist for much more than half a century, overweight and short of stature, with short legs. My bicycle is equipped with the lowest gears obtainable, sufficient to go up Mt. Everest without rising above the saddle; me, not Mt. Everest. Nevertheless, the invariable result of this setup- as used by me- is that I always end up walking up anything resembling a hill, much to the chagrin of fellow cyclists.

    I had never been to this part of Forest Hill. I started the ride with no difficulty, but as soon as I got close the hills started and they were not gentle slopes. I walked all the way up and was then pleased to find ‘BOWDON MOUNT’, Voigt’s old home. I did not walk all the way back.

    I laid my bicycle down by the side of the road and walked up yet another steep incline opposite the house into a lovely little park. The young Voigt must have had happy hours playing there.

    Returning to Bowdon Mount side I took out my camera and quickly walked into the forecourt to take a photo. I now know what it feels like to be a burglar ‘casing’ the joint. I was truly apprehensive that some burly macho type would come charging out and pummel me, my camera and my bicycle into a messy pulp. But nothing happened: silence, silence and yet more silence. I put my camera away and mused about what, if anything, I should do next.


    [​IMG]DSCN0534 by Round Person, on Flickr

    Bowdon Mount is the hastily taken and blurred photo (Ref:117/11) of the right half of a semi- detached brick building with security grill on the window. The white rectangular piece above the window is incised with the words ‘Bowdon Mount’.

    I summoned up my courage and rang the doorbell. A man came down stairs and opened the door. I apologised for disturbing him and explained that a famous engineer had lived here and asked whether he knew anything about him or any stories about his life here? The man told me he had never heard of Voigt. The rest of our conversation follows:

    ME: ‘Voigt was of German parentage but born and bred here and went to Dulwich College. He was a patriotic Briton.’

    HE: ‘Oh, I like him!’

    ME: ‘But he was discriminated against after the war because of his German ancestry, so emigrated to Canada.’

    HE: ‘Oh: then I don’t like him!’

    END OF CONVERSATION.

    [​IMG]
    DSCN0537 by pulitout, on Flickr
    ________________________________________________

    On 7 May 2014 Barniboy, the well known contributor to this thread, came to England. I again had the pleasure of going to Bowdon Mount this time by train and this time with Barniboy as my bodyguard. Some of the photos we took are below.

    First one taken downhill from the house on Honor Oak Park.

    [​IMG]_S900232 by Round Person, on Flickr


    Next, a general view of the frontage

    [​IMG]_DSF0254 by Round Person, on Flickr


    The concrete carved inscriptions above some of the windows ...


    [​IMG]_DSF0250 by Round Person, on Flickr



    a bit closer up...
    [​IMG]_DSF0251 by Round Person, on Flickr

    and a closeup...
    [​IMG]_DSF0257 by Round Person, on Flickr

    finally a happy Barniboy having taken photos...


    [​IMG]_DSF0247 by Round Person, on Flickr

    I should have said "semi-finally", because we then went to see the One tree hill park opposite side of the road from Bowdon Mount. Southwark Council, in its wisdom, has now fenced this off. This is somewhat off putting- comparing it with the last time I visited in its natural setting.

    Barniboy and I explored some of the park, but I show him (below) with the area opposite Bowdon Mount...

    [​IMG]_DSF0246 by Round Person, on Flickr
    It is not apparent from the photo, but the area behind the new ugly fencing is a quite steep incline.
     
  10. YNWOAN

    YNWOAN 100% Analogue

  11. lexi

    lexi pfm Member

    Very interesting Eguth. I like your train of thought about using the big band for evaluating the speakers. So many speakers like single unit and open baffle are impressive indeed on very simple music.......only to get a bit muddled as complexity increases.

    I did wonder once or twice what kind of system you had put together . :D
     
  12. eguth

    eguth pfm Member

    lexi

    Thanks for your ‘on topic’ post. It is refreshing to read relevant and useful posts on this thread that probe constructively.

    My own preference for quick evaluation- (quick only when absolutely necessary; slow long term evaluation being far superior if the goods warrant it) developed into insistence upon either big band or large orchestra because these have a variety of instruments and are much harder to reproduce realistically than smaller groups or individual instruments- easier sounds or fewer of them- lesser multiplicity. (I really don’t like the way I have put this, but for the moment please bear it).

    What upsets me about less than ideal reproduction of large groups of instruments is lack of ‘realism’. I know that this term needs clarification; my model for ‘realism’ is live music. Almost no system I have heard reproduces groups of various instruments so well that you are fooled into believing that you are at a live performance. The closest I have heard is the CARFRAE horn/single ended valve demo. But then I don’t run around listening to equipment. Those who do are better placed to make such comparative statements.

    Voigt stressed a point that is related to yours. He advised against putting his drivers on a baffle (whether open baffle or IB cabinet doesn’t matter). He was concerned about loading. He always advocated horn loading. At one stage he produced a cartoon ad for his products that warned against putting his drivers on a baffle. In one of the later instalments of this thread I will be posting pictures of some of his ads but this one is not one of them. You are out of luck, I am afraid. However, I will be giving detailed references so that anyone can find all of his cartoon ads if they wish.

    I always try to avoid getting into details of my system on Memoirs that are not directly concerned with it; however, since you are interested I have put some details elsewhere on different earlier threads on pfm.
     
  13. eguth

    eguth pfm Member

    MEMOIRS OF A DIY HI FI NUT - Part XVIII
    P.G.A.H. VOIGT: A Great Audio Inventor

    V
    Schooldays & University

    It must have involved sacrifice for Voigt’s parents to send him to Dulwich College a well- known, expensive, public school in south London with many famous ‘Old Boys’- including Ernest Shackleton & G.E. Moore, though Voigt remarked that it was fortunate that his parents could afford it.


    [​IMG]
    DSCN0735

    [​IMG]
    DSCN0733

    by pulitout, on Flickr



    [​IMG]
    DSCN0737 by pulitout, on Flickr

    [​IMG]
    DSCN0736 by pulitout, on Flickr

    [photos taken 28.2.12]



    I decided to see whether the college could throw any light on Voigt’s schooldays.

    From time to time I had gone to Dulwich College to attend public events so I am not entirely unfamiliar with its grounds and buildings. Nevertheless, I expected the ‘cold shoulder’, being a stranger with no introduction marching in unannounced and requesting information about long- deceased alumni.

    I could never have predicted the reception I was given. I was treated with impressive helpfulness and given access to the College Archives. This involved an additional administrative burden on staff. In case anyone thinks I am ‘touting up’ public schools I can assure them that I am against them, against faith schools and against every other socially divisive form of schooling. The reception I received from some other sources during the preparation of this Memoir was much inferior.

    The Dulwich College Register states that Voigt was born 9.12.1901 and entered School in September 1915, left (6th Form Engineering) in July 1919. His father’s occupation is given as ‘Manufacturer’s Agent’ and he lived at home at ‘Bowden Mount’. His father was an importer of buckram and his mother- whom he said had a great influence upon him- lived to age 103.

    Inspection of his progress via end of term reports revealed:

    Xmas 1915: Science & Engineering IVth: NO RECORD. This was his first year at the school.

    By the summer of 1916 in the Upper IVth, he was given a Prize and was first in his class of 27. The prize was for Geometrical & Mechanical Drawing.

    Between summer 1916 and summer 1919 he stayed near the top or somewhere near the middle of his class in most subjects.

    He received a lst class result in Maths in 1917.

    In summer 1919 he was given two VIth Form prizes: 1st out of a class of 10 in ‘Workshops’ and 1st out of 28 in Drawing (i.e. Mechanical & Engineering Drawing).

    Academic results, no matter how impressive, should be viewed alongside other things; so I looked further. I found nothing. However, in a letter to the College dated 19 July 1957 written from Toronto, Canada, Voigt give his old College due credit. He writes:

    “…To reminisce for a moment, it was under Lanky-Taylor, Buggy-Hutchins, Spongy-Russell that I learnt most of my basic engineering, with Mr. Crowther, Jimmy Bauer, Mr. Oldham and the Anachist (sic) Mr. Edwards and others on the job too. I always was interested in engineering, and I am certain that the excellent ground work absorbed during those years at Dulwich contributed greatly to my fundamental attitude to the subject ever since… (Cownlie) will tell you that though my ideas were often unorthodox, they usually worked. (Very largely thanks to my understanding of basics acquired at Dulwich.)” 1

    Voigt did the first year of the B.Sc at Dulwich, and thus entered UCL initially as a second year student. His master at Dulwich remarked that he was lucky to have passed his maths, a curiousity since he was awarded the prize in maths noted above. However, Voigt subsequently always said that his maths was weak, and he prefered an empirical approach.

    [​IMG]
    DSCN0799 by pulitout, on Flickr

    The above photo of Voigt (8" x 10 3/4", sepia toned) is of unknown date and place. On the back there is a rubber stamp that reads: "copyright to this photograph belongs to ELWIN NEAME, please acknowledge." Copyright hereby acknowledged 14.6.2012. Elwin Neame was a leading photographer who ran his business in Wimbledon. He died in August 1923. The photo of Voigt was, therefore, almost certainly taken in the early 1920s. Since the photo is not in colour it is not certain whether the tie he is wearing is a Dulwich College one but I think that, probably, it is and that the photo was taken on his completion at Dulwich. Perhaps someone from Dulwich can comment. The alternative is that the tie is a UCL tie and that the photo was taken at or shortly after his graduation from UCL.






    VOIGT'S ACTIVITIES AT CENTRAL HALL, PECKHAM‏




    [​IMG]_S291059 by Round Person, on Flickr



    It is not known what date this photo was taken, but I would guess that it is after the turn of the 20th century.



    Voigt was still at Dulwich College when he joined and actively participated in evening meetings of the Wireless and Experimental Association, a club in with branches in London and elsewhere. The club met at Central Hall, Peckham. They were designing and building radio sets and various other apparatus.



    [​IMG]Voigt demonstrating at the central hall Peckham by Round Person, on Flickr



    [​IMG]Voigt demonstrating 1 by Round Person, on Flickr



    The Voigt family believe that the lady in the second photograph is Ida Munro.18



    The earliest record of a Voigt contribution to the Wireless and Experimental Association was in 1920 when, in February, he read a paper on inductances and related how he obtained unusual efficiency. In September of that year he read another paper Re: losses in inductance in wireless plant and also described an ingenious switch for connecting head gear telephones in series or parallel.

    The following month he traced transformation of energy from electrical to mechanical circuits and demonstrated advantages of having telephones of the same resistance as the crystal detector.

    According to the Association Report, on March 19, 1921, Voigt cleared up points about pancake coils and their use, and in April he gave a lecture on the construction and use of logarithm tables. In June 1921 he was elected to represent junior members and in July “Mr. Voigt dealt with electrostatic attraction between metals and semi insulators”.

    Further details of Voigt’s contributions to the Association can be followed through the references given in the Reference Section of this thread.



    Voigt’s jampot tuner and a member’s set made from MKIII tuner parts are shown below as photographed at an Association meeting. He was then studying at UCL.

    [​IMG]Voigts jampot tuner and a members set made from MKIII tuner parts by Round Person, on Flickr



    Voigt’s accumulator plate- making machine and early tuning coil.

    [​IMG]Voigts accumulator plate making machine and early tuning coil by Round Person, on Flickr



    Central Hall, Peckham looks rather different today….



    [​IMG]_S261041 by Round Person, on Flickr



    [​IMG]_S271044 by Round Person, on Flickr

    The original entrance has been removed and replaced.

    [​IMG]_S161027 by Round Person, on Flickr



    However, the stairs leading to the auditorium are still as original and the auditorium itself is largely unchanged, though refurnished. (All the recent photos of Central Hall were taken in 2014).



    The following illustrates how one of Voigt’s contributions was described in Wireless World:



    [​IMG]_S301061 by Round Person, on Flickr



    UCL

    After leaving Dulwich he entered University College, London in 1920, and in 1922 was awarded a B.Sc in electrical engineering.

    You will see the Pender Electrical Engineering Laboratory (below) where Voigt carried out his studies.

    [​IMG]
    DSCN0745 by pulitout, on Flickr
    [​IMG]
    DSCN0746 by pulitout, on Flickr

    The UCL Record Office has provided the following documents:

    [​IMG]
    Untitled by pulitout, on Flickr

    [​IMG]
    Untitled2 by pulitout, on Flickr

    [​IMG]
    untitled 3 by pulitout, on Flickr


    [​IMG]
    Untitled by pulitout, on Flickr


    IDA FLORENCE MAY MUNRO (born August 19,1900) seems to have met Paul Voigt in about 1920 when they were both studying Electrical Engineering at UCL.

    At that time she was living with her family in Southfields, near Wimbledon. She did her London Matriculation at Wimbledon High School and University Tutorial College, and passed in 1919.

    Her father must have approved of her friendship with Voigt, because by 1922 he had upped sticks and moved the family home to Chesterton, Canonbie Rd., Honour Oak, SE23- about a 5 minute walk from the Voigt family home in Honour Oak Park, Forest Hill. This was, presumably, to make access easier and to enable Ida and Paul to travel to UCL together, thereby facilitating Electrical Engineering.

    Ida joined the WES (Women’s Engineering Society) on 4 April 1921. She later draughted and signed plans for Voigt’s loudspeakers.

    Her UCL records show that she obtained a Certificate in Engineering in 1922, but there is no UCL record of her having been awarded a degree.

    [​IMG]GENERAL CERTIFICATE OF ENGINEERING by Round Person, on Flickr






    The following UCL index card shows that she obtained the Certificate (see lower right hand corner).

    [​IMG]IDA UCL record 4index card side 1 by Round Person, on Flickr




    They were married in 1928 in a church about half way between their two family homes.


    [​IMG]DSC09616 wedding by Round Person, on Flickr

    Ida died in 1994 or 1995 at Belleville Hospital, Brighton, Ontario, Canada.

    If anyone has any further information about her I would be pleased to receive it.

    ___________________________________________
     
  14. Kevin11

    Kevin11 pfm Member

  15. eguth

    eguth pfm Member

    Once you stuff a Voigt pipe it becomes a transmission line. But Voigt did not go in for stuffing. In the case of the Voigt corner horn he did use his ¼ wave pipe (bass chamber) for the lowest frequencies, but for political reasons did not use the word ‘resonator’ when describing it (I rely for the accuracy of this statement on something he later said about his ¼ wave patent). The corner horn utilised a tractrix horn for the mid/highs, much better than a ¼ wave for these frequencies because it does not compromise the correct horn shape to save space.

    There are a large number of D.I.Y. designs based on Voigt's pipe.
     
  16. eguth

    eguth pfm Member

    MEMOIRS OF A DIY HI FI NUT - Part XVIII
    P.G.A.H. VOIGT: A Great Audio Inventor

    VI​

    Inventiveness​


    [for information about Voigt's early life and photos please read from the beginning of this thread (page 1)]


    Voigt’s drawing ability and inventiveness was not limited to engineering: he regularly created his own advertisements, some of them cartoons (for examples see The Gramophone, 1937). Recently some have been republished.7 He never repeated an ad with cartoon once it was published. He could have had career as a cartoonist.

    Voigt ADS- The Gramophone, Nov. 1937 & March 1938

    [​IMG]Voigt ADS- The Gramophone, Nov. 1937 & March 1938 by Round Person, on Flickr



    In 1936 Voigt wrote a formal letter to Dulwich College. It is typed on his firm’s printed stationery. The letter states that a Director of the firm advises that he credits Voigt with being the first to demonstrate stereo in England. The Director in question was Voigt himself and he signed it himself. Voigt evidently had a wry sense of humour.


    [​IMG]Letter from Voigt DSCN0623 by Round Person, on Flickr



    He developed or invented loudspeakers, a tractrix horn, velocity and capacitor microphones, amplifiers, transformers, MC cutters and pickups.4 In the 1920s, while employed by J.E.Hough Ltd., he developed an MC pickup (in Voigt’s own words):

    “…so that records did not have the hysteresis distortion of moving iron ones…musicians could not tell from the gramophone in use just how good or bad a recording was…we needed a good speaker…”

    Voigt speaks of listening through a ‘hole in the wall’ (was he listening to Bessie Smith a lot?) [to learn exactly what he meant read Reference No.23. Basically, he regarded the ideal as transporting the listening room to the concert hall and listening to what is coming from the stage through an open window]. He described his corner horn as “listening through a window”. It utilized his quarter wave pipe (bass chamber) behind his double cone driver with a front-mounted tractrix horn for the mids and highs.

    As if all these inventions were not enough for one man he also published speculation on gravity only to later discover that his ideas had been anticipated by Le Sage about 200 years earlier.6 He was interested in the unknowns of science including the structure of gravitational, magnetic and electrical fields.

    In 1927 Voigt was still working for W.E.Hough Ltd. at the factory in Glengall Rd. off the Old Kent Road in the London Borough of Southwark. John Gilbert met Voigt. The meeting came about in a curious way. Gilbert’s father had first come across Hough by chance in a bank in Borough, in Southwark. They chatted. Gilbert’s uncle was an engineer with the BBC and things developed from there. Old Hough told John Gilbert that he had difficulty with Voigt. Hough, evidently, was not alone in this.


    It was all ‘string and sealing wax’ in those days. John Gilbert worked with Voigt at Edison Bell- at the same factory that used to be W.E.Hough Ltd. before it folded. The two firms were closely connected. Voigt was designing amps, and Gilbert says he learned a lot from him.

    [​IMG]DSCN0625 by Round Person, on Flickr







    [​IMG]_S411096 by Round Person, on Flickr






    [​IMG]_S431098 by Round Person, on Flickr

    [​IMG]_S481104 by Round Person, on Flickr



    The previous four photos come from an in- house private publication about the history of Edison Bell. It does not have a date of publication, but since the title page states ‘history down to 1924’ the photos must have been taken at about that time. Voigt was, at that stage, in the Wireless section.8

    The agreement with Hough Ltd. was that Voigt was entitled to patent what he developed during his employment. In 1927 he was granted British patent NO.278098 for a tractrix horn.9

    He was a very empirical worker. He preferred trial to maths. John Gilbert recalls that Voigt decided to record Beethoven’s 5th without any attenuation of bass. 1 minute is the maximum time you could get onto a 12” record at full amplitude. Gilbert says you can see the wiggles in the grooves. It was a completely uncommercial project.

    Voigt was always hard up: he used cheap plywood. Later on, in 1937, he developed a condenser (capacitor) microphone: the BBC used it. It crackled in the humidity. Its frequency range was far beyond broadcast capabilities. It was crude, which was typical of most things he produced.

    From about 1929 he lived at No. 53 Church Rd., Upper Norwood, with his wife Ida.

    No. 53 no longer exists. It was part of a row of identical attached houses. The rest of the row still stands. I have taken a photo of the house which is closest to where No. 53 stood. This is, I believe, what No. 53 looked like.

    [​IMG]
    House in Church Rd. Upper Norwood by pulitout, on Flickr

    Gilbert was a good friend and housed some of Voigt’s equipment in his home during the war while Voigt was employed in the Ministry of Information. He had two of Voigt’s corner horns in his home. They were heavy. Woodworm infested them. In 1984 he said that “they still sound wonderful”.

    Gilbert regards Voigt as the most outstanding engineer before the war….“he created a sensation at the Institution of Electrical Engineers”.

    I have been into the Institution of Electrical Engineers on a number of occasions. I have found the atmosphere to be electrifying. I like to think that Voigt, amongst other eminent engineers, is responsible for this. The architecture of the place is engaging; in a style that I would describe as indescribable- though this may be incorrect.

    [​IMG]
    DSCN0739 by pulitout, on Flickr
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  17. markse

    markse pfm Member

    “…so that records did not have the hysteresis distortion of moving iron ones…musicians could not tell from the gramophone in use just how good or bad a recording was…we needed a good speaker…”

    That's interesting Eguth- Hysteresis Distortion. I have never heard that term before and never in an MC-MM-MI debate. I wonder if it is a real concern or just a theoretical one in cartridges? Or does it explain the supposed superiority of MC designs?
    Mark
     
  18. markse

    markse pfm Member

    I did a search and found reference to a moving coil cutter Voigt designed which he is quoted as describing thus:

    "I think I scored with less distortion as, with the moving coil cutter, the hysteresis distortion common to most moving iron systems was eliminated."

    http://www.gramophone.net/Issue/Page/December 1965/128/788946/PAUL+VOIGT+and+EDISON+BELL

    Did he claim the same for MC cartridges? I guess it must play a part in all magnetic core coil systems but how much in the tiny generators of a cartridge?

    Mark
     
  19. eguth

    eguth pfm Member

    markse

    I don't know the answer to your questions.

    In response to them I have now done a Patent search for the years 1924-1940. I was hoping that the patent would answer your questions.

    However it appears that, although Voigt developed the MC pickup, he did not apply for a patent on his design.

    His point about moving iron hysterisis distorion would also apply to MI cartridges.

    If no pfmer knows the answers you could do research.

    My view is that with cartridges so much depends upon the listener, the system, the speakers, the room, that generalisation about any one or two aspects is not likely to be conclusive.
     
  20. markse

    markse pfm Member

    I just find it strange that this potential pitfall of MI or MM technology has not been highlighted before in the multitude of arguments regarding the different available technologies- to my knowledge- I could be wrong.
    maybe it was a real issue in cutting heads where I suppose the coils are MUCH larger and the amount of iron involved also MUCH larger- perhaps it's a non-issue with the motors involved in cartridges- would be interesting to hear others opinions.
    Mark
     

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