title: Do you know a good and efficient FFT?
body: <p>I am trying to find a very fast and efficient Fourier transform (FFT).  Does anyone know of any good ones.  I need to run it on the iPhone so it must not be intensive.  Instead, maybe you know of one that is wavelet like, i need frequency resolution but only a narrow band (vocal audio range up to 10khz max...even 10Khz might be too high).  Im thinking also of truncating this FFT to keep the frequency resolution while eliminating the unwanted frequency band.  This is for an iphone</p>
  
  <p>...I have taken a look at the FFT in Aurio touch but it seems this is an int FFT  but my app uses floats.....would it give a big performance increase to try and adapt program to an int FFT or not(which i really dont feel like doing...plus aurio touch uses a radix 2 FFT which is not that great).</p>