For some reason I have trouble with questions like this. How would I get the phase difference if I were given the time delay of two loudspeakers side by side? I'll use this question as an example: "The speakers are now placed side by side. If the wire to speaker 1 is passed through a box that delays the signal by 1.56 ms, what is the new phase difference? " The frequency is 392 Hz The PD would be zero since they're beside each other the speed is 340 m/s the wavelengths are 0.86 m and the time delay is 1.56 ms or 1.56e-3 s I was able to find the period, 2.55e-3 s But after this I kinda blank out. Any tips?