10
It is important to consider level variation in distributed systems design, and not assume that every
location within a listening space will be at the same level – or can achieve the same maximum SPL
– as does a location directly under a speaker.
7DEOH
/HYHO9DULDWLRQ'XHWR/D\RXW3DWWHUQ 'HQVLW\
Layout Pattern and Density
Level Variation within
the Listening Space
SQUARE PATTERN
Maximum Overlap
-1.4 dB
Minimum Overlap
-2.0 dB
Edge-to-Edge
-4.4 dB
1.4 x Edge-to-Edge
-6.8 dB
2 x Edge-to-Edge
-10.4 dB
HEXAGONAL PATTERN
Maximum Overlap
-1.2 dB
Minimum Overlap
-2.6 dB
Edge-to-Edge
-5.4 dB
1.4 x Edge-to-Edge
-10.2 dB
2 x Edge-to-Edge
-17.3 dB
Audience Mobility Considerations – Seated audiences, such as in a restaurant, can be bothered by
excessive level variation throughout the space because one table can be disturbed by a high sound
level at the same time that another table can’t hear the music or paging adequately. In some
applications where the audience is walking around, such as in a retail or grocery store, there may be
slightly more of an expectation of variations in coverage.
Room Characteristics -- In any choice of coverage pattern, room obstacles, microphone locations,
seating areas and any requirements for quieter areas should be considered.
Rough Guideline for Layout Density -- The following rough guidelines are for seated venues.
Denser spacing, where it is economical to accomplish, will usually result in better performance than
wider spacing:
Low-Level Background Music Only – Wider spacings, such as edge-to-edge spacing is usually
acceptable.
Background Music with Basic Paging – Spacing of edge-to-edge or tighter is usually acceptable
for basic paging.
Music with High Quality Paging – Minimum overlap spacing is often required for clear, even
intelligibility.
Heavy Speech Reinforcement – In spaces that are used heavily for speech reinforcement, such as
meeting rooms, it is important to space the speakers closely enough to provide as even coverage
as possible. Minimum overlap spacing or full overlap spacing is recommended for these
applications.