BS 6840-5(1995) : 1995 AMD 9409

1 Scope
2 Object
SECTION ONE - GENERAL
3 Conditions
    3.1 General conditions
    3.2 Conditions for the measurement
4 Test signal
    4.1 Sinusoidal signal
    4.2 Broadband noise signal
    4.3 Narrow band noise signal
    4.4 Impulsive signal
5 Acoustical environment
    5.1 Free-field conditions
    5.2 Half space free-field conditions
    5.3 Diffuse sound field conditions
    5.4 Simulated free-field conditions
    5.5 Half-space simulated free-field conditions
6 Unwanted acoustical and electrical noise
7 Positioning of loudspeaker and measuring microphone
    7.1 Measuring distance under free-field and half
         space free-field conditions
    7.2 Positioning of loudspeaker in diffuse field
         conditions
    7.3 Positioning of loudspeaker and microphone in
         simulated free-field conditions
8 Measuring equipment
9 Accuracy of acoustical measurement
10 Mounting of loudspeakers
   10.1 Mounting and acoustic loading of drive units
   10.2 Mounting and acoustic loading of a loudspeaker
         system
11 Standard baffle
12 Preconditioning
SECTION TWO - CHARACTERISTICS TO BE SPECIFIED AND THE
              RELEVANT METHODS OF MEASUREMENT
13 Type description
   13.1 Loudspeaker drive units
   13.2 Loudspeaker system
14 Marking of terminals and controls
15 Reference plane, reference point and reference axis
   15.1 Reference plane
   15.2 Reference point
   15.3 Reference axis
16 Impedance and derivative characteristics
   16.1 Rated impedance
   16.2 Impedance curve
   16.3 Total Q-factor (Qt)
   16.4 Equivalent air volume of a loudspeaker drive
         unit compliance (Vas)
17 Input voltage
   17.1 Short term maximum input voltage
   17.2 Long term maximim input voltage
   17.3 Rated sinusoidal voltage
   17.4 Rated noise voltage
18 Input electrical power
   18.1 Short term maximum power
   18.2 Long term maximum power
   18.3 Rated sinusoidal power
   18.4 Rated noise power
19 Frequency characteristics
   19.1 Rated frequency range
   19.2 Resonance frequency
   19.3 Tuning frequency of a bass reflex or passive
         radiator loudspeaker system
20 Sound pressure under free-field and half space free-
    field conditions
   20.1 Sound pressure in a stated frequency band
   20.2 Sound pressure level in a stated frequency band
   20.3 Characteristic sensitivity in a stated frequency
        band
   20.4 Characteristic sensitivity level in a stated
        frequency band
   20.5 Mean sound pressure in a stated frequency band
   20.6 Mean sound pressure level in a stated frequency
        band
21 Response under free-field and half space free-field
    conditions
   21.1 Frequency response
   21.2 Effective frequency range
   21.3 Transfer function
22 Output power (acoustic power)
   22.1 Acoustic power in a frequency band
   22.2 Mean acoustic power in a frequency band
   22.3 Efficiency in a frequency band
   22.4 Mean efficiency in a frequency band
23 Directional characteristics
   23.1 Directional response pattern
   23.2 Radiation angle
   23.3 Directivity index
24 Amplitude non-linearity
   24.1 Introduction
   24.2 Total harmonic distortion
   24.3 Harmonic distortion of the nth order
   24.4 Characteristic harmonic distortion
   24.5 Total noise distortion
   24.6 Noise distortion of the nth order'
   24.7 Characteristic noise distortion
   24.8 Modulation distortion of the nth order
   24.9 Characteristic modulation distortion of the nth
        order
  24.10 Difference frequency distortion
  24.11 Noise intermodulation distortion
SECTION THREE - OTHER CHARACTERISTICS AND CLASSIFICATION
25 Rated ambient conditions
26 Interfering stray field
27 Physical characteristics
   27.1 Dimensions
   27.2 Weight
   27.3 Cable assemblies
28 Design data
29 Classification of the characteristics to be
    specified
Table
1 Characteristics to be specified and classification
Figures
1 Standard baffle, dimensions (Clause 11)
2 Standard baffle with chamfer (Clause 11)
3 Standard baffle with sub-baffle (Clause 11)
4 Restricting and clipping network (see 17.4.2)
Annex
ZA (normative) Other international publications quoted
    in this standard with the references of the relevant
    European publications

Gives the characteristics to be specified and the relevant methods of measurement for loudspeakers using sinusoidal or specified noise signals. Applies to sound system loudspeakers, treated as entirely passive elements. BS AMD 9409 RENUMBERS THIS STANDARD