This paper proposes a new spectral transformation for speaker normalization. We use the Bilinear Transformation (BLT) to introduce a new frequency warping resulting from a mapping of a prototype Band-Pass (BP) filter into a general BP filter. This new transformation called "Band-Pass Transform" (BPT) offers two degrees of freedom enabling complex warpings of the frequency axis and different from previous works with BLT. A procedure based on the Nelder-Mead algorithm is proposed to estimate the BPT parameters. Our experimental results include a detailed study of the performance of the BPT compared to other VTLN methods for a subset of speakers and results on large test sets. BPT performs better than other VTLN methods and offers a gain of 1.13% absolute on Hub-5 English Eval01 set.