The new methods use a frequency domain for the optimalization of the delay parameter . The algorithms of calculation take as criterium extreme of sum second power of imaginary part of a complex spectrum. The complex spectrums of echos are calculated by FFT and the criterium for is:

This criterium is in case of even function minimum, in the case of old function is maximum. The applications of delay in a frequency domain have possibilities to move echos to the intermedial position of samples and as result eliminated the transport delay.