User Manual

Multichannel Monitoring Tutorial Booklet (M2TB) rev. 3.5.2

Masataka Nakahara : SONA Corporation

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3-1-3. Center speaker placement

Rec. ITU-R BS. 775-1 recommends that the L, C, and R speakers all be placed at the same height (ear

level). Thus, if the playback environment includes video, an acoustically transparent screen is

recommended. If an acoustically transparent screen is not used, it is stated that the center speaker should

be placed immediately above or below the screen (CRT).

3-1-4. LFE (sub-woofer) placement

Rec. ITU-R BS. 775-1 mentions systems that include an added LFE system (optional), but does not

specify the placement of the sub-woofer speaker for playback. However, the playback bandwidth is

specified as 20 Hz--120 Hz (Annex 7). Also, while the playback level is said to be under consideration, it

is stated that it is useful to provide gain in the range of +10--+12 dB as with film.

3-1-5. Monitoring distance

The distance from the listening point to each speaker (the monitoring distance) is not explicitly stated in

Rec. ITU-R BS. 775-1, but the Rec. ITU-R BS. 1116-1

[2]

cited as a reference does recommend a

monitoring distance of two to three meters for a multi-channel playback environment.

Rec. ITU-R BS. 775-1 is the basis of a surround monitoring environment, but in cases such as the

following, it may be better to consider other speaker placements.

1. When dynamic surround panning such as fly-overs are an important means of acoustical expression,

such as in films.

2. When many of the target end-uses for your productions are at variance with the ITU-R placement, and

you want to give consideration to compatibility with these end-users.

3. When it is difficult to implement the ITU-R configuration in the room (studio). Or, in cases in which

forcibly implementing the ITU-R configuration produces an unnatural sound field. For example if you

implement the ITU-R configuration in an extremely narrow room, the surround speakers would be

placed directly beside your ears, producing an unnatural-feeling surround playback.

The ideal speaker placement will depend on the size of the room, the monitoring radius (the distance from

the speakers to the listening point), and the acoustical treatment of the room (absorption, diffuseness,

etc.).

Thus, decisions regarding speaker placement must take into account both the character of the media

produced in the studio and the physical environment of the studio (the size of the space, the monitoring

radius).

It is important for the production people to have an understanding of his or her own surround playback

environment. In particular if you are considering a configuration other than the ITU-R (which is often

called the standard for the playback environment), it is important to understand the characteristics of your

particular playback environment.

Speaker placement is determined largely by two factors; the angle of L-R separation, and the placement of

the surround speakers.