EQ

3-band parametric equalizer using biquad filters.

#What it demonstrates

Biquad filter DSP (Direct Form II Transposed)
Per-sample coefficient updates from smoothed parameters
Logarithmic parameter ranges for frequency and Q
Section-based grid layout (LOW, MID, HIGH)
Auto-bypass when band gain is near 0 dB
f64 end-to-end via use truce::prelude64::* — biquad coefficient computation is precision-sensitive (especially at low Q × low frequency). On formats with a 64-bit wire (VST3, VST2, CLAP) the plugin processes the host's f64 buffers directly; elsewhere the wrapper widens host f32 at the block boundary so the DSP path stays in f64 either way.
Legacy state migration — the reference migrate_state implementation: a pre-truce EQS1 blob translates into truce params, tested with assert_state_migration (and assert_state_migration_rejected for blobs the plugin must refuse). See the state guide.

Name	Range	Unit	Description
Low Freq	20 to 1000	Hz	Low band center frequency
Low Gain	-18 to +18	dB	Low band boost/cut
Low Q	0.1 to 10	--	Low band width
Mid Freq	200 to 8000	Hz	Mid band center frequency
Mid Gain	-18 to +18	dB	Mid band boost/cut
Mid Q	0.1 to 10	--	Mid band width
High Freq	1000 to 20000	Hz	High band center frequency
High Gain	-18 to +18	dB	High band boost/cut
High Q	0.1 to 10	--	High band width
Output	-18 to +18	dB	Output trim