# Maximum interference of frequencies

1. Aug 6, 2008

### baylorbelle

A microphone is located on the line connecting two speakers that are 0.650m apart and oscillating in phase. The microphone is 2.25m from the midpoint of the two speakers. What are the lowest two frequencies that produce an interference maximum at the microphone's location?

okay, so i have my diagram:

I know that the basic formula is L2-L1=m$$\lambda$$ , but whenever i do my math, find $$\lambda$$, and convert it to Hz using f=c/$$\lambda$$, I keep getting 4.0*10^8. I don't know where I'm messing up or how I need to approach this problem to even get two answers. Any guidance is appreciated!

Last edited: Aug 6, 2008
2. Aug 6, 2008

### LowlyPion

What speed of sound are you using?

I use 343 m/s in air. What are you using?

3. Aug 6, 2008

### baylorbelle

it figures it would be a simple mistake like that. I was using the speed of light instead of the speed of sound. Thanks for clearing up my careless error.

4. Aug 6, 2008

### LowlyPion

That's a start then. Have you figured out the rest of it ok?