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Figure 6. ITU-R BS.775-1 Recommended Loudspeaker Positioning in Recording Studios
around 100-200 Hz) and the loudspeaker is loaded which increases the entire bass output. Subjec-
tively, the result is a muddy but thin sounding bass and midrange masking which makes speech less
intelligible. For additional advice on loudspeaker placement, see Section 2.5.2 Center Loudspeaker
Enclosure Location. Conversely, be careful that the ceiling reflection does not start to dominate
instead.
The front loudspeakers can be placed such that the center loudspeaker is a maximum of 7° higher
or lower than the left and right loudspeakers. This will not be audibly disturbing to the listeners as
the human ear is not good at localizing in the vertical direction (zenith plane). The rear loudspeak-
ers can be positioned at a maximum of 15° higher (lower is not practical!) than the front loudspeak-
ers as humans are less good at localizing sounds to the rear.
3.2
Subwoofer Positioning
Below are some recommendations for subwoofer positioning:
•
Close enough to the front wall and slightly offset from the middle of the room, 30 cm (1 ft), to
avoid the first pressure minima position.
•
In a corner, close to both front and side walls. This position will maximize the system efficiency
due to the corner loading. A second subwoofer in the opposite corner may be required to
avoid localizing a single subwoofer. Alternatively, use a lower bass management crossover
frequency such as 60 or 40 Hz (be careful that the main loudspeakers can handle the
remaining upper bandwidth - see Section 3.3 Bass Management.
These locations are contrary to the common belief that the best position for the subwoofer is in the front,
on the floor and in the middle of the room, equidistant from the side walls. This location can be a serious
compromise since the subwoofer sits in the pressure minimum of the lateral standing wave. Also, it has
to remembered that:
•
Adjustment of the gain (Input Sensitivity) and frequency response (Bass Roll-off) of the
subwoofer is necessary to balance the subwoofer to main loudspeakers.
•
The subwoofer can also be flush mounted into the front wall or some cabinetry but the
discussion of the position of the source relative to the room remains valid.
•
The phase adjustment on the subwoofer at the crossover frequency is important to achieve
a flat frequency response in the crossover region.
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