Study and Design of Second-Order Differential Arrays - Study and Design of Differential Microphone Arrays - page 80

80 80

60 60

40 40

20 20

0 0

0 ◦ 60 ◦ 120 ◦ 180 ◦ 240 ◦ 300 ◦ 360 ◦

Θ N

0 ◦ 60 ◦ 120 ◦ 180 ◦ 240 ◦ 300 ◦ 360 ◦

Θ N

( a ) ( b )

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60 60

40 40

20 20

0 0

0 ◦ 60 ◦ 120 ◦ 180 ◦ 240 ◦ 300 ◦ 360 ◦

Θ N

0 ◦ 60 ◦ 120 ◦ 180 ◦ 240 ◦ 300 ◦ 360 ◦

Θ N

( c ) ( d )

80 80

60 60

40 40

20 20

0 0

0 ◦ 60 ◦ 120 ◦ 180 ◦ 240 ◦ 300 ◦ 360 ◦

Θ N

0 ◦ 60 ◦ 120 ◦ 180 ◦ 240 ◦ 300 ◦ 360 ◦

Θ N

(e) (f)

FIG. 4.20 The gain of the second-order cardioid for a point noise source, as a function of
Θ N , for several frequencies and two values of Δ : (a) F =0 . 5 kHz, Δ = 1 cm, (b) F =0 . 5 kHz,
Δ = 2 cm, (c) F = 1 kHz, Δ = 1 cm, (d) F = 1 kHz, Δ = 2 cm, (e) F = 3 kHz, Δ = 1 cm,
and (f) F = 3 kHz, Δ = 2 cm.