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1H loudspeaker array type 1h: horizontally mounted, placed under the glass surface, measurements (height x
width x mounting depth) 1.80 x 0.14 x 0.12m
1V loudspeaker array type 1h: vertically mounted, foot placed 1.80m above foor level, measurements (height x
width x mounting depth) 1.80 x 0.14 x 0.12m
2 loudspeaker array type 2: vertically mounted, foot placed 1.80m above foor level, measurements (height x
width x mounting depth) 2.80 x 0.14 x 0.12m
S small additional speaker: hung from the ceiling of enclosed spaces, measurements (height x width x
mounting depth) 0.30 x 0.20 x 0.20m
fg 17 Communication (PA) system: plan of the lay-out of the loudspeakers
Integrated public address (PA) system
The speech intelligibility levels can be considerably increased by opting for a PA
system that projects sound towards the travelers in a narrow wave. In this way, the
reverberation field is not affected, increasing speech intelligibility levels above the
statistical values which were at least “reasonable” and in many places “good” in
any case.
The proposed sound source for the PA system for this design is a “loudspeaker
array”. This is a long, slender speaker cabinet containing a row of loudspeakers.
An internal signal processor controls the phase difference between the different
speakers so that a narrow pattern or spread is projected. A loudspeaker array has
two important advantages over a classic speaker cabinet or speaker column:
- Greater directivity; the reverberation field is less affected
- A larger area can be covered; fewer speakers are necessary making the
open, unobstructed zones larger.
Because of their slender design, the speaker arrays can be fully integrated into the
architecture. The competition design proposes the following lay-out:
- The speakers project towards both ends of the platform from an axis of
symmetry located at the centre of each platform. Time t = 0 is the centre of
the platform. A time-delayed sound signal is transmitted to the speakers
located farther from the centre of the platform to compensate for the natural
delay of the sound wave. In this way, there is no echoing of the transmitted
sound messages.
- Two vertical speaker arrays, each projecting towards one side, are placed
at the centre of each platform. These vertical arrays are integrated into the
walls of the heated refuges. Their projection range is equal to a platform
length of roughly 35 m.
- A loudspeaker array is placed at every point of support spanning one platform
length to the next point of support. The array is horizontally integrated in the
sign panels of the points of support with a canopy. The glass canopy which