Libsoxr

Four SoX Resampler quality levels are available for constant-rate resampling in Audacity; which one to use in different circumstances may be selected in the Preferences/Quality menu. Note that the names assigned to these levels differ from those used by the 'sox' command-line utility; equivalent names are shown in the following table:

See the 'rate' effect in the SoX manual for details (frequency response, etc.) of each of these quality levels.

For variable-rate resampling, libsoxr uses a single, dedicated quality level; this is selected automatically by Audacity when performing a task that requires it.

For comparison purposes, the following table attempts to place in order of increasing quality, current resampling qualities (with libsoxr), and those with resamplers available in previous/other configurations of Audacity: