How can you use an Oscilloscope and 2 Microphones to find the Wavelength of a Soundwave?

-First set the Oscilloscope up correctly so that you get 2 Waves for the Microscopes [Has a Separate Wave] -Then, have the Microphones next to the Speaker, and slowly distance one away until the 2 Waves align each other, but has moved 1 Wavelength apart -Measure the Distance between the Microphone to find the Wavelength -Then, using whatever you put as the Frequency for the Signal Generator, you can find the Speed