Abstract: Abstract Free field to Eardrum Transfer Function (FETF) is one of the major factors influencing the identification of the sound source direction.The FETF can be employed to generate a Virtual Acoustic Space (VAS) by computer and other equipment.In this paper we have approached the methods to improve the measurement and estimation of FETF.LMS method was suggested to estimate FETF for single pulse measurement.The computer simulation results have shown that LMS method is much better than empirical FFT method.This paper also gives a simple description of excitation signals for measuring the impulse response of FETF.