BS 6840-17:1991

Committees responsible
National foreword
Methods
1. Scope
2. Definitions
3. Reference indication
4. Reference voltage
5. Reference volume
6. Division of the scale
7. Amplitude-frequency response - Performance
     requirement
8. Response time
9. Overswing - Performance requirement
10. Return time - Performance requirement
11. Reversibility error - Performance requirement
12. Input impedance - Performance requirement
13. Distortion introduced by the standard volume
     indicator - Performance requirement
14. Temperature range - Performance requirement
15. Overload input level - Performance requirement
16. Rectifier - Performance requirement
17. Colour of scale and scale card
18. Mounting on panels - Presence of magnetic material
19. Mounting angle - Performance requirement
20. Classification of the characteristics to be
     specified
Figures
1. Connection of the standard volume indicator
2. Schematic diagram of the method of measurement
     of response time of the standard volume indicator
3. Scale of the standard volume indicator
Table
1. Attenuator characteristics 3,900 omega constant
     impedance
Annex
ZA. (informative) Other international publications
     quoted in this standard with the references of
     the relevant European publications
National annex
NA (informative) Cross-references

Defines the characteristics, methods of measurement, scale colours and standard scale markings, and requirements for a built-in or external attenuator for VU indicators (VU-meters) for use in recording studios and broadcast control rooms.

This standard gives the characteristics to be specified, performance requirements and the relevant methods of measurement for electro-mechanical volume indicators. The concept of “volume?? is a practical way of assigning a numerical value to the magnitude of electrical speech and music programme signals.

Since the response of the meter movement of such an indicator to the rapidly varying programme voltage is greatly dependent upon its dynamic characteristics, a standard for volume measurements shall therefore include a specification of these characteristics. The term “vu?? (pronounced “vee-you?? and written with lower case letters) is used to express volume in terms of vu above or below a specified reference level.

This standard does not deal with peak programme level meters which are the subject of IEC 268-10.