The study of the resampling and requantization methods of digital audio data is one of the major assets project. Which these methods used to compression the audio data. In this search the application of some resampling methods on the audio signal was investigated by reducing the number of samples while the audio quality is maintained. The considered resampling methods are the Linear, Quadratic, Cubic spline, Lagrange and Bezier and for each method the level of sampling reduction was investigated by applying the down sampling rate using and then up sampling using the above mentioned interpolation method. The efficiency of each method under consideration will be determined with the aid of quality criteria like peak signal to noise ratio (PSNR). The Lagrange, Cubic spline, and Beizer interpolation methods provided have the same results and good quality.Also in this search the results of applying the uniform and non–uniform quantization methods are presented the effect of the quantization steps on the audio quality investigated. The results proved the uniform quantization method is better than non–uniform quantization method.A listening test was used to prove the efficiency of each method, the test sample has different backgrounds and they prove when the decimation rate and the step of quantization increase the audio quality will be decrease
