Recollections of BBC engineering from 1922 to 1997
The British Broadcasting Corporation
web site is:

ETD Information Sheets - Audio


AUDIO Information Sheets



Routeing and Monitoring

Recording and Reproduction

Systems and Standards

Testing and Measurement


Principles Of Microphones I - Pressure Operated (60F) (1978)

Principles Of Microphones II - Pressure Gradient (60G) (1978)

Principles Of Microphones III - Cardiodt (60H) (1978)

Principles Of Microphones IV - Transducers (60J) (1978)

Highly Directional Microphones  (1964)

TV Sound OPs Microphones and their Applications (53J) (1982)

Effect Of Sound Source Distance On The Output Of A PG Microphone  (1962)

An Introduction to BBC Loudspeakers (47K) (1980)

Loudspeakers - General Principles (47H) (1978)

Loudspeaker Polar Diagrams  (1964)

Power amplifiers  (1980)

BBC Transistor Audio Frequency Amplifiers  (1964)

Transistor Amplifier (63J) (1978)

Investigation Into BBC Amplifiers (33H) (1976)

Valve Amplifiers AMC/5, GPA/4, C/9 And MNA/3 (33G) (1965)

Amplifier AMC/5 Circuit (35M)

Amplifiers GPA/4 And GPA/4A Circuit (46D)

Amplifier C/9 Circuit (44L)

Amplifier MNA/3 Circuit (46A)

Wiring And Testing A One Valve Amplifier  (1959)

Sound Desks  (1976)

Introduction to TV Sound Desks Part 2 (40W) (1976)

Introduction to TV Sound Desks (40T) (1982)

52C_Introduction To Sound Desks - Part 1 (1971) New in June 2020

65L_Sound Desks - Basic Principles (1972) New in June 2020

27C_Radio Studio Sound Control Desks (1969) New in June 2020

28A_Control Room 50V Alarm Systems (1971) New in June 2020

Television Sound Desks  (1984)

WN & Bush House Control Rooms Operating Instructions  (1964)

Studios  (1975)

Studio 1 Basic facilities (60D) (1974)

Type A, B & C Studio Block Diagrams  (1963)

Type D Stereo Continuities - B.H. Extension Circuit Details 

The Continuity Interchange Unit (33D) (1976)

Introduction to 13 Channel PCM Equipment (27B) (1980)

Line-Up Of Programme Chain  (1964)

Peak Programme Meters  (1964)

ME12/9 PPM - Performance And Re-alignment (52H) (1975)

Theory Of The Hybrid Coil (35N) (1976)

The Hybrid Transformer  (1964)

The Hybrid Transformer (34B) (1975)

Introduction To Jackfields (58C) (1979)

The Three Jack System  (1964)

Outside Broadcast Equipment OBA/8  (1964)

Outside Broadcast Equipment OBA/9  (1964)

Technical Instruction - Sound in Syncs (49H)

An Introduction to NICAM3  (1983)


Audio Lines  (1982)

Audio Lines (18Y) (1983)

Audio Line Termination (18W) (1983)

Audio Frequency Line Transmission Practice (50P) (1973)

Line Transmission Theory 1  (1982)

Impedance of Unloaded Audio Lines  (1985)

Audio Lines Experiment 2 - Loaded Circuits  (1985)

Equalisation of Audio Lines (29L) (1978)

Equalisers (43A) (1967)

Sound Equalisers  (1969)

Permanent Audio Equaliser Design  (1978)

The Transmission of Stereo Signals on Lines (27D) (1973)

Stereo Phase Equalisers (27M) (1976)

DC & AC Testing Of Lines  (1964)

13 Channel P.C.M. Equipment (1972) New in June 2020

Routeing and Monitoring

Programme Switching In Sound Broadcasting (35D)

Sound Monitoring (35B) (1975)

R3/R4 Network Switching (36D) (1976)

Ext Services, Bush House - Assembly & Routing Of Prog Services (51A) (1976)

Motor Uniselector (35L) (1975)

Allocation Of Levels For A Group Uniselectors (32Y) (1972)

Operation Of Uniselectors With C&D Codes (32S)

Maintenance Of High Speed Motor Uniselector (35C) (1975)

Recording and Reproduction

Disk Cutting And Reproduction  (1964)

Principles Of Disk Reproduction (28H) (1975)

Principles of Disk Reproduction (later) (28H) (1980)

45A_Magnetic Recording & Reproduction (1967) New in June 2020

Magnetic Recording of Analogue Signals (21P) (1982)

Magnetic Recording Data And Graphs  (1964)

Audio Magnetic Recording Standards (18S) (1983)

49M_Recording - Tape Transport Systems (1969) New in June 2020

Tape Recorder Mechanical Maintenance  (1976)

Speed Variation in Audio Recorders (18T) (1982)

Maintaining The Signal Performance Of A Tape Recorder (41C) (1976)

Tape Editing 1 (62G) (1977)

Line-up Procedure For Tape Machines In Channels (4A) (1971)

Line-up Procedure For Tape Machines In Recording Channels (5B) (1972)

Description & Lineup Of ETD Recording Channels 

Stereo Tape Machine Lineup (48K) (1982)

Studer A80RC Stereo and Twin Track Lineup (48J) (1980)

Philips Tape Recorder EL3566 (3B) (1976)

Studer A62 (22G) (1972)

Studer C37 (30G) (1972)

Studer A710 Line-up (1984) Radio Engineering Services Report R426 (1984) New in June 2020

Test Cassettes (1984).pdf Radio Engineering Services Report R440 (1984) New in June 2020

Portable Tape Machines 2 - Nagra III & IV-S (56D)

Portable Tape Machines 1 - Uher 4000L & 4000IC (56C) (1976)

Tape Transport Control Circuitry  (1976)

Dub Editing Instruction No. 2  (1964)

Wiping Fades  (1964)

What To Do If A Tape Breaks During Replay  (1964)

Systems and Standards

Acoustics Units (33B) (1975)

Studio Acoustics (Definition Of Terms) (34P) (1974)

Acoustic Design Of BBC Studios (45W) (1972)

Room Resonances  (1964)

Sound Levels And Hearing Impairment (33A) (1975)

Sound Control - Basic Principles (65L) (1980)

The Sound Programme Chain (34C) (1975)

Microphone To Aerial (44D) (1980)

The SB System (58J) (1980)

Simultaneous Broadcasting  (1968)

PPM Levels For Different Programme Types  (1964)

TV Sound Control And Modulation Range  (1963)

Stereo - Basic Terms And Definitions (49B) (1975)

Principles Of Stereo (48M) (1974)

Introduction to Stereo Broadcasting (18M) (1983)

Stereophonic Broadcasting  (1968)

FM Graphs (18E)

Quadrature Demodulation (3F) (1980)

Noise Reduction Systems Summary 

Broadcast Operations Practicals 1-5 

Radio Services (34M) (1976)

25T_Introduction To Sound (1971) New in June 2020

Transmitter Sound Modulation Levels New in June 2020

Testing and Measurement

Audio Testing and Measuring  (1983)

Measurement of Audio Signals (52D) (1983)

Audio Testing And Measurement (18P) (1983)

Introduction To A.C. Test Equipment (34D) (1975)

Introduction to the EP14/1 A.C. Test Set (37T) (1983)

How to use the EP14/1 A.C. Test Set (37U) (1983)

A.C. Testing (37S) (1982)

A.C. Testing Questionnaire (37W) (1976)

Radio Broadcast Programmes And Their Measurement (52D) (1975)

Radio Broadcast Programmes and Their Measurement (later) (52D) (1978)

Programme Measurement (64F) (1977)

Programme Meters (25W) (1975)

Ferrograph Test Set - Investigation (33J) (1976)

Audio Tape Recorder Performance Testing (41A) (1975)

Tape Recorder Mechanical Testing  (1976)

Testing Amplifiers  (1964)

Testing Amplifiers (39A) (1971)

The Use of the Abbreviation dB in BBC Audio Practice (53E) (1979)

The Audio Signal (64A) (1977)

Sound Waves (47C) (1977)