It appears that the new Civic Auditorium in San Francisco was dedicated and "Magnavox" equipment
was installed to reinforce the voice of the Speakers. Governor Hiram Johnson was supposed to be present, but was unable to attend in person due to e severe cold.

It was therefore arranged to run a special line between the Governor's home in Green Street San Francisco and the Auditorium, in order to transmit the message. Pridham was at the Governor's home with a microphone, and Jensen was at the Auditorium. Hiram Johnson sat in front of the fireplace and delivered his speech which was heard in the Auditorium some miles away.

This demonstration proved that it would henceforth be feasible to build still larger structures and halls if they were equipped with "voice amplifier's" and, also a person could successfully address large gatherings at a distant place.

This information would prove that the first outside broadcast was done for Public Address which makes our industry older than Broadcasting, for at this time no public Broadcasting had taken place.

PERFECTING THE THERMIONIC VALVE 1914 - 1918

It is fitting that our Association, being the only one in the world devoted solely to PA.,should celebrate the fiftieth anniversary of the first ever use of loudspeakers to "address the public".

The story starts in Denmark, in 1886, with the birth of Peter L Jensen. In 1903 he started an apprenticeship with Valdemar Poulsen, assisting in the development of the famous Poulsen, arc transmitter and in work on early magnetic recorders. He was sent to San Francisco in 1909 to supervise the installation of a Poulsen arc system.

Then in 1911 he founded the "Commercial Wireless and Development Company" with Edwin Pridham, and Richard O,Connor as financial backer.

The name of the company was changed to the "Magnavox Company" later, coined from the Latin for "Great Voice"

In 1911, they discovered the remarkable characteristics of the moving coil principle for sound reproduction, the first patent being filed in January 1913.

In 1915 they built a dynamic loudspeaker using a one inch voice coil, a three inch corrugated diaphragm coupled to a horn about 34" long, with an opening of some 22". The electromagnet for the field attained a gap flux close to 11,000 gauss.

For their first experiment with the speaker they used a heavy duty carbon microphone as used in early transmitters, where the total aerial current passed through the mike. Upon connecting a 12 volt battery they set up a violent acoustical feedback, the very first PA howl!.

The loudspeaker was immediately placed on the roof.
On this day, for the first time ever, the amplified spoken word was heard. The records say that clear speech was heard one mile away with a cross wind!

They set to and developed an improved microphone employing four carefully selected carbon button units on a common diaphragm. This was the system that they set up at the Panama-Pacific Exposition held in San Francisco for a few days, providing mysterious music heard across the Bay.

The "Magnavox" was officially presented as a working system on Christmas Eve 1915, to an estimated crowd of 100,000 peoples. "They heard carols and speeches with absolute distinctness" say the reports

On July 3 rd 1916 Pridham and Jensen applied for a patent on a Sound Magnifying Phongraph.

In 1918 they built their first valve amplifiers. By 1919 they standardised on a 3 stage unit with a 25 watt power output valve. In this year the ailing President Wilson addressed a gathering in the San Diego Stadium via a Magnavox system.

During 1919 and 1920 The Magnavox system was used by many notables, including former President Taft, Harding and Franklin D. Roosevelt. At the Dempsey-Carpentier fight in 1921 a Magnavox announcing system was used.

In the period 1919-1920 the giant American Telephone & Telegraph Company, through Western Electric, entered the P.A. field and the Magnavox Company with its meagre resources, decided to concentrate on other applications of the loudspeaker.

Fortunately the tidal wave of demand for radio speakers had started and the famous model R3 was born, many thousands of these came to England in the twenties.

In 1925 Jensen resigned from the Magnavox Company, setting up to manufacture under his own name. He remained in charge of Jenson Radio until 1940. He spent his remaining years producing styli and other gramophone components until his death on October 26 th, 1961. Pridham remained with the Magnavox concern and passed away in January 1963.

Early Public Address Car

WESTERN ELECTRIC DOUBLE BUTTON MICROPHONE 1922

VINTAGE AMPLIFIERS

In 1925 King George V used the equipment at the opening ceremony of the Wembley Exhibition where his speech was distributed by only six of these long range loudspeakers to a crowd of approximately 90,000 people assembled in the great stadium.

It was on this important occasion that the value of public address was impressed upon the organisers of public functions throughout the country, who found it necessary to have sound distributed over large areas occupied by the public.

In the same year amplifying equipment was used for the Royal Air Force Pageant at Hendon, where a large number of loudspeakers was installed, so that the commentator could explain to the audience the evolutions during each item of the pragramme,and, between events, the music of the band could be distributed throughout the whole system.

A leaflet mentions the equipment to cover the Schneider Trophy Race in 1929. Two hundred horns were used, the weight of the amplification equipment came to the impressive figure of twenty tons.

It is not difficult to realise what a boon public address has proved to the organisers of such events and to the public attending them, for a lucid explanation of the evolutions that are taking place adds immensely to the interest of the sightseers

In the field of sound amplification from gramophone records considerable development has taken place and to-day the reproduction on really good public address apparatus is as near to the original as seems possible.

The gramophone record is also used largely in conjunction with public address apparatus for propaganda work. Political speeches are recorded on gramophone records by party leaders and reproduced to large crowds at political galas and even at street corners, by means of mobile public address equipment.

The Silver Jubilee of King George V , 6 th May 1935. The illustration shows the Royal Procession in the Mall, on the return journey to Buckingham Palace from the Thanksgiving Service in St Pauls Cathedral. The Marconi loudspeakers, can be seen attached to the lamp-posts, which were used to relay the proceedings to the waiting crowds.

THE SILVER JUBILEE OF KING GEORGE V, 6thMAY 1935

The Marconi Public Address and Music
Amplifying System 1922

The development of high quality microphones and speech amplifiers required for establishing and perfecting what is known as "broadcasting" has opened up a new extremely important field in the practical application of acoustic science.

Except for the circumstances of its inception and for the fact that some of the apparatus we are about to describe may, if required, be used in conjunction with a radio transmitter or a radio receiver, this system has nothing whatever to do with wireless.

We refer to what is commonly known as public speech and music repetition equipments whereby sound can be immensely magnified without distortion and projected by means of loudspeakers to an assembly of people either in the same vicinity or at some distant point quite remote from the source of the sound.

This system is likely to revolutionise present day methods of public address and is rapidly being introduced in many other ways, not only for civil, but also for naval and military purposes.

Before describing the apparatus offered by the Marconi Company for this purpose, let us assume for the moment that such apparatus is available, and that by its means even the weakest sounds can be picked up by a microphone and reproduced with the required degree of magnification at any desired point.

Very little imagination is needed to visualise some of the extraordinary possibilities which the use of such apparatus brings within our grasp. For example, a man may address an assembly of many thousands of people without raising his voice above the tone he would adopt if he were addressing a mere handful of people in a small room.

With a suitable distribution of the actual sound projectors the whole of his audience, even those unfortunately situated in the furthest corners of the hall or cathedral, would be able to hear every word spoken.

The volume of sound delivered by the loudspeakers can be increased by the mere turning of a regulating handle on the amplifiers

A somewhat similar use to which such an apparatus can be put is the broadcasting of instructions of information by word of mouth in shipyards, works, large railway stations, or in naval and military operations where, in the ordinary way, a man's voice, owing to the prevailing din and racket, is only able to carry for a distance of a few yards.

The availability of these mains operated power sources, together with the rapid advancement in valve technique, led to the production of some of the earliest high quality power amplifiers designed specifically for Public Address purposes.

TANNOY RADIO SHOW 1926

MOVING COIL 1930's

By 1928 the already wide range of equipment was in increasing demand by the promoters of many national events in the spheres of sport and entertainment and another five years saw TANNOY established as the largest organisation in Great Britain specialising solely in the design and manufacture of complete Public Address equipment. A fully equipped Laboratory had come into existence, possessing unique, specially designed measuring apparatus, and it was not unnatural that much equipment of this type was in demand by other manufacturers.

It is interesting to note that the first and only officially acknowledged measuring equipment available in this country became known as the TANNOY N.P.L. Noise-meter, which was developed in close collaboration with the National Physical Laboratory, measuring in phons, and capable of measuring sound with an earlike response. It was the only one of its type available with N.P.L. Certificate of Accuracy.

MOVING COIL 1930's

In 1937, a Public Address system was installed at Hendon Aerodrome for the Air Pageant that year. The requirements were carefully investigated on a scientific basis, using the newly available TANNOY Noise-meter, and it was this installation which opened the eyes of the authorities to the far reaching possibilities of loudspeaker systems for use on Aerodromes during times of national emergency.

By this time also, the value of Public Address systems was appreciated in the world of music and drama. An outstanding example of installation where fidelity of performance was of paramount importance was the pre war production of 'Hiawatha', 'Faust' etc., at the Royal Albert Hall.

HAND RIBBON 1950's

HENDON 1937

SUPER HIGH POWER SOUND RADIATOR FARNBOROUGH 1953

The outbreak of the war in 1939 made fresh demands upon the TANNOY research and manufacturing organisation and during the six years that followed, TANNOY developed and produced many items of proprietary equipment designed solely for use by various branches of the forces. On airfields and gun sites, in tanks and submarines, the name TANNOY became synonymous with reliable communication. Over 600 complete airfield communication systems were designed installed and maintained for the R.A.F. alone.

UNIQUE TANNOY POWER MICROPHONE.

OVER THREE QUARTERS OF A MILLION USED BY ALL BRANCHES OF THE ARMED SERVICES

With the return of peace, TANNOY'S efforts were again directed to the provision of equipment for all spheres of activity. Some of the first and largest installations were supplied to Butlin's Holiday Camps, which were built and completed in record time. Many Greyhound Racing Association Stadia, White City etc,were equipped and many leading industrial organisations were supplied with equipment for staff location, time signalling and production control.

MICHAEL FOOT ELECTION RALLY 1930'S

To illustrate the diversity of the organisations' activities it is interesting to note that when the best in High Fidelity music reproduction for the home is required TANNOY has become the natural choice of those to whom quality is of paramount importance.

BERTRAM MILLS CIRCUS - OLYMPIA

The name Tannoy
1926

Commercial accumulator charges required for the manufacture of wireless sets used mercury vapour rectifiers, which were relatively expensive. In attempting to devise simpler and cheaper solutions, Fountain came up with an electrolytic rectifier which was simple and reliable enough for home use. To do this he used two different metals - 'tantalum' and a lead 'alloy'. By simply putting together the words 'tantalum' and 'alloy', Fountain gave the world 'Tannoy'.

MOVING COIL 1960's

1
Monitor Panel - Type MLS/V2M This panel provides facilities for checking aurally, by means of a Loudspeaker, and visually, by means of a meter, the performance of the system. It also includes facilities for checking, by means of a meter, the condition of the amplifying valves.
2
Output Switch Panel - Type OSM/8 This Panel provides facilities for switching individual Loudspeaker circuits as required. The maximum number of switches that can be accommodated on a single panel is twelve, and they may be used for switching Loudspeakers direct or for operating the necessary relays where remote control is required.
3
Radio Receiver In the rack illustrated an FM Radio Receiver is incorporated, covering the 85 to 100 M/cs band, but other types, including pre-tuned and manually tuned AM receivers or communication type Receivers , are available.
4
Input Relay Panels These provide for the remote selection of input channels by means of relays, they also include pre-set volume controls to enable the volume level of the various circuits to be properly set with respect to each other.
5
Manual Control Panel - Type ICM/3SM Input Control Panels are available, providing mixing facilities for up to four channels together with a selection switch for radio or gramophone. Where necessary these Panels may have controls of a pre-set variety.
6
Warning Note Oscillator A wide variety of Warning Signals is available, giving from one up to a total of six highly distinctive warning notes. They are all capable of remote operation and in many cases may be used in conjunction with programme and master control clocks.
7
Voltage Amplifier The Voltage Amplifier is used to raise the level of the input signals from microphones, radio receiver or gramophone to a sufficiently high level to drive a number of power amplifiers. Comprehensive frequency adjustment circuits are included to enable the best results to be obtained under varying acoustic conditions, an interstage gain control is also provide to enable the optimum signal to noise ratio to be obtained.
8
Power Amplifier A wide variety of power amplifiers is available, having outputs ranging from 10
Watts to 200 watts. Some of the smaller types do not require a separate voltage amplifier and may be operated directly from a microphone or other source.

9
Mains Distribution Panel MP/1S Switched and fused mains' outlets are provided for the various types of chassis included in each rack cabinet. This ensures that in the event of a failure of an individual item the serviceability of the remainder will in no way be affected.
10
Relay Supply Unit A number of such units are available providing an independent low voltage D.C. supply for operating the various input and output relay circuits and, where necessary, indicator lamps. Generously rated mains transformers, metal rectifiers and smoothing circuit are incorporated.

TANNOY VALVE RACK ASSEMBLY SYSTEM 1950'S

RIBBON 1939