User Manual

Multichannel Monitoring Tutorial Booklet (M2TB) rev. 3.5.2

Masataka Nakahara : SONA Corporation

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3. Playback environment

The playback environment consists of two aspects; room acoustics (which include the room shape,

absorptivity, reflectivity, and diffusivity characteristics), and speaker placement.

This chapter will discuss speaker placement.

Discussions of music-related media commonly refer to Rec. ITU-R BS. 775-1

[1]

([Fig. 19])

recommendations. For other media as well, references are often made to ITU-R standards, or to

compliance with the above-discussed DVD-Video environment.

3-1. Rec. ITU-R BS. 775-1

The ITU-R speaker placement is a recommendation (Rec.) set forth by the International

Telecommunication Union -- Radio Communication Section.

Rec. ITU-R BS. 775-1 (Multi-channel Stereophonic Sound System With and Without Accompanying

Picture) was produced by the radio communication sector of the ITU under the impetus of the advent of

HDTV (1992-1994). For this reason, most broadcast stations take Rec. ITU-R BS. 775-1 as the standard

for their playback environment. This speaker placement is also acknowledged as the standard one for a

wide range of playback environments, including music production.

If you want to apply a uniform standard to your production environment, or if you do not have special

intentions regarding the playback sound-field, it is desirable to adopt the ITU-R placement for your

playback environment.

3-1-1. ITU-R speaker placement

[Fig. 19] Rec. ITU-R BS. 775-1, in case of using one loudspeaker for each LS and RS

The main features of the ITU-R placement are as follows.

Note: In addition to a layout placing one surround speaker each for LS and RS, Rec. ITU-R BS.755-1 also

describes layouts that place multiple speakers. However in this document we will discuss only the first of

these.

1. L/R angle of separation = 60˚

This emphasizes compatibility with conventional audio listening environments (an equilateral triangle

consisting of L<->R<->listener).

2. Surround speakers (LS, RS) placement angle = 110˚ ±10˚ (with C located at 0˚ in the plane)

60°

100°

120°

<15°

LS,RS

L,C,R

1.2m

110°