JPH05303389

PURPOSE:To generate a sound with a fixed formant even though the sound is read with a varied pitch. CONSTITUTION:Low frequency components of engine sounds with a frequency characteristic, in which levels are reduced at a constant slope in the lower frequencies to the higher frequencies direction, are processed so that these levels become approximately constant conditions from the lower frequencies to the higher frequencies and stored in a storage means 10. Moreover, high frequency components of the engine sounds, in which levels are reduced at an approximately constant slope in the lower frequencies to the higher frequencies direction, are processed so that these levels become approximately constant conditions from the lower region to the higher region and stored in a storage means 18. Address generating means 12 and 20 read stored values from the means 10 and 18 at a same pitch, respectively and supply them to filter means 14 and 22. The means 14 and 22 have frequency characteristics which have approximately same slopes as the low frequency components and the high frequency components, thus, each component of the stored values, which are read with a constant condition for each component level, is reduced with the same slope of the original low frequency components and the high frequency components so as to obtain a fixed formant.