Changing the volume of a singer or instrument is very useful but a sound desk can also increase or decrease specific frequencies in order to produce a better sound. These EQ (equaliser) controls can be thought of as sophisticated tone controls and are probably the most difficult part of mixing.

High pass filter This button cuts off all frequencies below around 100Hz, ensuring that footsteps, bass drums etc. are not heard. High frequency On most desks, this acts just like a tone control, boasting or reducing the high frequencies. High-mid frequency EQ Frequency selection: This control selects which frequency is affected by the equaliser. Note that because it is a parametric EQ, surrounding frequencies will also be affected but to a lesser extent. Increase/reduce selection: This control enables you to boost or cut the frequency by a variable amount. Low-mid frequency EQ Frequency selection: This control selects which frequency is affected by the equaliser. Note that because it is a parametric EQ, surrounding frequencies will also be affected but to a lesser extent. Increase/reduce selection: This control enables you to boost or cut the frequency by a variable amount. Low frequency EQ On most desks, this acts just like a tone control, boasting or reducing the low frequencies. EQ in/out This button activates the EQ settings, affecting the sound signal.