ISO 2969:2015 pdf download.Cinematography — B-chain electro-acoustic reponse of motion-picture control rooms and indoor theatres — Specifications and measurements
1 Scope
This International Standard specifies the measurement methods and characteristic electroacoustic frequency response of the B-chain of motion-picture dubbing theatres (mixing rooms), screening rooms, and indoor theatres whose room volume exceeds 125 m 3 (4,414 ft 3 ). It is intended to assist in standardization of monitoring and reproduction of motion-picture sound in such rooms. The goal is to have constant perceived loudness and frequency response from installation to installation, and from position-to-position within an installation. This International Standard does not cover that part of the motion-picture sound system extending from the transducer to the input source audio selector.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1 complete sound reproduction system
system used in indoor theatres and screening rooms and in motion-picture sound post-production facilities such as dubbing theatres, mix rooms and ADR control rooms
Note 1 to entry: The complete system in an indoor theatre or review room is generally considered to consist of an A-chain and a B-chain.
Note 2 to entry: Represented diagrammatically in Figures 1 and 2.
2.2 pre-emphasized audio track
audio record, either magnetic or photographic, containing high-frequency boost equalization, which is intended for playback over de-emphasized theatre playback systems
Note 1 to entry: Now very rarely used, but found on all films prior to the mid-1970s. Part of the playback de-emphasis was generated by use of Curve-N in previous versions of this standard (see 2.10 and A.10).
2.3 wide-range audio track
audio record, either magnetic, analogue photographic or digital, which is intended for playback over theatre playback systems aligned to this International Standard
Note 1 to entry: This characteristic was previously referred as Curve-X (see 2.9). Such tracks are recorded without fixed pre- and de-emphasis. Analogue wide-range soundtracks invariably use noise reduction companding technology.
2.4 A-chain (transducer system)
part of a motion-picture audio system extending as far as the input source selector, as shown in Figures 1 and 2
2.5 B-chain (final chain)
part of a motion-picture sound reproduction system, as shown in Figures 1 and 2, commencing at the input source audio selector and terminating in the listening area
3.2 Sound pressure level (SPL) vs. Frequency measurements (see Annex A) shall be made as follows:
a) On dubbing stages (in mixing rooms), at each of the principal listening positions, such as at the position of each of the mixing personnel, and at the producer’s location. In rooms with a single primary listening position, care should be taken that this is not an aberrant location;
b) In screening rooms, at a sufficient number of positions to cover the listening area and to reduce the standard deviation of measured position-to-position response to less than 3 dB. This will typically be achieved with four positions;
c) In indoor theatres, at a minimum with the position S as shown in Figure 4, and normally at a sufficient number of additional other positions to reduce the standard deviation of measured position-to- position response to less than 3 dB. This will typically be achieved with four positions (see A.3.5). An extra series of measurement positions will have to be added if the theatre has a balcony.
ISO 2969:2015 pdf download
