A hearing aid device suitable for executing a frequency compression is optimized to achieve a better assignment between channels of a source frequency range and channels of a target frequency range. A frequency range that can be transmitted by the hearing aid device is split into a number of frequency bands, after which a number of adjacent frequency bands are combined into at least one group of frequency bands and then one frequency band is selected from each group of frequency bands. The selected frequency bands are moved respectively into a target frequency band permanently assigned to the respective group. This prevents that a number of frequency bands from the source frequency range are shifted to the same target frequency band.