
Answer:
from the midpoint we must move 1.34 m to any side and there is no sound
Explanation:
The sound waves are longitudinal waves that can have interference, for this to occur the difference in the path of the waves must be equal to an integer number of half wavelengths for the case from constructive interference and a semi-integer number for destructive interference.
Δd = 2n λ/2 constructive interference
Δd = (2n + ½) λ/2 destructive interference
Where n is an integer
At the midpoint between the two speakers the interference is always constructive, the two distances are equal, so the road difference is zero
Let's calculate the wavelength with the relationship
v = λ f
λ = v / f
λ = 344/641
λ = 0.537 m
We place the expression for the first destructive interference (no sound)
n = 1
Δd = (2 1 + ½) 0.537
Δd = 1.3425 m
This means that from the midpoint we must move 1.34 m to any side and there is no sound