As many might know, I am a not a fan of "Noise Dependent'’ recording techniques for EVP research. Methods that use ‘noise’ for EVP recording have been used for decades, with the line of thought that noise is needed for voice formation. This requires that any sort of random or chaotic noise is employed in recording sessions. The "Noise Dependent" methods raises the percentage of misidentication to a very high degree. 

The method of ‘Noise Independent’ recording techniques means NO external noise is added to a recording session. The quiet room or controlled environment recording is difficult, time consuming, and arduous, so may be a deciding factor in why people steer away from it in the field.