The diagrams below gives EQ knob settings and corresponding response curves for a typical low-mid-high equalizer: Low Shelf Low frequency cuts are useful when the sound is boomy or muddy sounding, ...

A third option is to frequency-double a gas laser to shift ... offers a broad selection of products spanning the mid-infrared range. Lasers are available at wavelengths of 3.8, 4.71, 7.23, 7. ...