Thank's.
Here, the frequency response (using headphone preset).
Improve firequalizer
avfilter/graphparser: allow specifying filter@id as filter instance
avfilter: take_samples: do not directly return frame when samples are skipped
avfilter/firequalizer: fix blackman window calculation
fate: add test for firequalizer filter
avfilter/firequalizer: change WFUNC_MIN/MAX to NB_WFUNC