Homework Help: Maximum sound and wave problem

1. Jun 9, 2014

Daltohn

1. The problem statement, all variables and given/known data
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.

2. Relevant equations
v=fλ

3. 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.

2. Jun 9, 2014

Vibhor

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 ?

3. Jun 9, 2014

Daltohn

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!