[Feature request] - Equal loudness compensation plugin

[aqxa1]

Hi, A plugin that compensations for changing loudness perception at different volume levels would be nice. Along the lines of this loud-comp-stereo lsp-plugin and the corresponding discussion. In essence, by changing the volume level, the frequency response would be adjusted based on equal oudness curves: with mids essentially being lowered relative to bass (and treble to a lesser extent) as volume is lowered, in line with hearing being less sensitive to those frequencies at lower volume levels.