What is the Lowest Frequency for Maximum Loudness at Point P?

[Daltohn]

Homework Statement

Speakers L_1 and L_2 are placed at a 2 m distance from each other. The speakers send out soundwaves that are in the same phase and the loudness (?) is examined in the point P (see figure). The velocity of the sound is 343 m/s and the distance L_2P is 6 m.

L_1


L_2 P (right triangle)

a)Which is the lowest frequency that causes a maximum in P?

b)Which is the highest frequency that causes a minimum in the point P?

Answer is 1060 and 528 Hz.

Homework Equations

v=fλ

The Attempt at a Solution

With maximum, do they mean that both the sound waves should have antinodes at the same time in P? I've been trying different ways but I'm not getting it.

 

[Vibhor]

With maximum, do they mean that both the sound waves should have antinodes at the same time in P?

Maximum means constructive interference . The waves travel different distances while reaching point P . What should be the path difference if the waves were to interfere constructively ?

 

[Daltohn]

Maximum means constructive interference . The waves travel different distances while reaching point P . What should be the path difference if the waves were to interfere constructively ?

Got it, in a) lambda is 2sqrt(10)-6, in b) that is lambda/2. Understand now. Interference could be constructive without being maximum though, maximum is optimal constructive interference I guess. Thanks for the help!