virtual void highlight_treble(unsigned bus_idx, bool highlight) = 0;
virtual void highlight_mid(unsigned bus_idx, bool highlight) = 0;
virtual void highlight_bass(unsigned bus_idx, bool highlight) = 0;
virtual void highlight_treble(unsigned bus_idx, bool highlight) = 0;
virtual void highlight_mid(unsigned bus_idx, bool highlight) = 0;
virtual void highlight_bass(unsigned bus_idx, bool highlight) = 0;