Auditory Tactics
Philippe Pasquier and Philippe-Aubert Gauthier, 2007
Auditory Tactics
Philippe Pasquier and Philippe-Aubert Gauthier, 2007
Create a sound installation
which includes spatial sound technologies
... but not just for the fun of it :
use spatial sound as a conceptual,
significant or esthetical component
of the artistic proposition.
Auditory Tactics
Philippe Pasquier and Philippe-Aubert Gauthier, 2007
● Intentions ... ● Plan of the
– Explore the notions of presentation:
private and public – Loudspeaker array
auditory spheres in a (workshop theme) and
public space with a beam-forming
sound installation:
● Beam-forming to create
– The design process
small private zone of – Speaker selection
sound radiation ...
● Use voice sound ... – The fabrication
– Explore the spatial – Pure-Data patch
sound possibilities with – The in situ installation
BF and the building ...
– Play!
Auditory Tactics: Beam-Forming?
Auditory Tactics: Beam-Forming?
Auditory Tactics: Beam forming?
A single loudspeaker ...
y [m]
x [m]
Auditory Tactics: Beam forming?
Two loudspeakers ...
y [m]
x [m]
Auditory Tactics: Beam forming?
Four loudspeakers ...
y [m]
x [m]
Auditory Tactics: Beam forming?
Eight loudspeakers ...
y [m]
x [m]
Auditory Tactics: Beam forming?
Private auditory spheres
Sixteen loudspeakers ...
y [m]
x [m]
Auditory Tactics: Beam forming?
A different delay ...
y [m]
x [m]
Auditory Tactics: Beam forming?
End firing ...
y [m]
x [m]
Auditory Tactics : Bessel array
Public auditory spheres
y [m]
x [m]
Auditory Tactics: The Design
● Initial technical
constraints:
– Need a compact array
of full-bandwidth
loudspeaker: coax
speakers.
– Design an array:
closed-box
Car 4-inches 4-ohms speakers
loudspeakers.
– Save money: car
audio.
Auditory Tactics: The Design
● Importance of baffling the
loudspeakers: cancellation
of the acoustical short-
circuit, very effective at low
Push-pull: Acoustical
freq. short-circuit without
baffle
The baffle [1] cancels the
acoustical short circuit and [2]
increases the sound radiation!
Auditory Tactics: The Design
Realistic baffling: Closed box or vented box?
Closed box ma
ka ka
Vented box
k and m k and m
ma
ka ka
Auditory Tactics: The Design
Realistic baffling: Closed box or vented box?
Vented Closed
Auditory Tactics: The Design
● The closed-box
design:
– Easier to design and tune.
– More safe for dust and
other intrusive objects. Box vol.: 0.33 Cuft
● Selecting the box
volume: typical car
audio speakers ...
● Found the minimum
box size that adds
stiffness ... (ka)
Auditory Tactics: The Design
Effect of the baffle: baffle step and corner diffraction
Freeware: The Edge,
version 1.8 for Windows
Auditory Tactics: The Design
Speakers
Top cover
Boxes
Grill cloth
Box and array design
Auditory Tactics: The Design
Auditory Tactics: The Design
Auditory Tactics: Speaker Selection
● Paramaters: Rendement n
4,00
– Sensibility dB 1W/1m 3,75
3,50
3,25 =10
M −109/ 10
3,00
Gives efficiency (%) to
Rendement n (%)
● 2,75
2,50
convert electric power 2,25
2,00
in acoustical power. 1,75
1,50
1,25
Example: 90dB 1W/1m 1,00
0,75
gives1.25%! 0,50
0,25
0,00
– Maximum RMS power 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95
Sensibilité M [dB 1W/1m]
● Max electrical power
(P) gives max
acoustical power (E):
E=nP with the
efficiency n.
Auditory Tactics: Speaker Selection
● Paramaters:
– Number of speakers: increase in acoustical power:
– LWarray = LW 10 log 10 N
– +3dB when doubling N
10log(N)
14
13
12
11
Gain en dB (10log(N))
10
9
8
7
6
5
4
3
2
1
0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
N
Auditory Tactics: Speaker Selection
● Estimation of the direct reproduced sound pressure
level for the total acoustical power of the array
L p =L Warray −20log 10 r −11
D
Champ direct SPL [dB]
120,00
110,00
100,00
90,00
80,00
SPL [dB]
70,00
60,00 Column B
50,00 Column C
40,00
30,00
20,00
10,00
0,00
01122334455667788991111111111111111111122222222222
, , , , , , , , , , , , , , , , , , , 0011223344556677889900112233445
5050505050505050505, , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,
Distance [m]
Auditory Tactics: The Fabrication
Each loudspeaker
is in front of a
independent cavity.
Auditory Tactics: The installation
Auditory Tactics: Pure-Data
Auditory Tactics: Pure-Data
Auditory Tactics: The workshop!
● Using loudspeaker array?
● Closely spaced loudspeakers.
● Experiment with two-channel array:
– Try to explore the radiation patterns.
– Play with phase and gains in PD ...