title: FFT processing of audio sample
body: <p>I am novice in audio processing with mathematical background so I have few (a lot, but few for starters) questions about processing extracted samples with fft. </p>
  
  <p>I am using fft implementation from <a href="http://www.drdobbs.com/cpp/a-simple-and-efficient-fft-implementatio/199702312?pgno=1" rel="nofollow">http://www.drdobbs.com/cpp/a-simple-and-efficient-fft-implementatio/199702312?pgno=1</a> with fixed array length.</p>
  
  <p>I have some set of samples (lets say 1024 samples in set). </p>
  
  <p>Fft algorithm which takes input complex values (real and imaginary), imaginary values are set to 0, because I don't have any and stripping fft output of it's imaginary part. </p>
  
  <p>I have next questions:</p>
  
  <p>1) Is my assumption that samples are real numbers correct?</p>
  
  <p>2) Is there efficient implementation of FFT which work only on real 
  numbers? I mean there is no imaginary part at all in calculations.</p>
  
  <p>3) If I continue using described process, is it correct assumption that if there is no imaginary data in input of fft (all zeros), imaginary part of fft output will be also zero for all values? </p>
  
  <p>PS I am sorry if question already exist but I didn't find any satisfying answer on my questions. </p>