Every industry has a few rules of thumb that they use as a guide or starting point for certain processes. Here are some that I have collected over the years that pertain to the recording studio.

    Microphone Selection

• Use a dynamic microphone for loud or high-impact sounds.
• Use a condenser microphone for soft or high-frequency sounds.
• Use a ribbon microphone to make things sound silky or less bright.

    Microphone Polar Patterns

• Use omnidirectional microphones
 ■ to avoid coloration such as the proximity effect or off-axis effects.
 ■ to capture the room sound.
 ■ to provide a natural, blended sound.
 ■ when recording a moving source, such as a performer who moves around.
 ■ when using stereo recording techniques such as
     • the A-B or spaced omnis technique.

• Use cardioid microphones
 ■ to control bleed from nearby sounds.
 ■ in rooms with poor acoustics, to minimize reflections.
 ■ to isolate drums in a drum kit.
 ■ in live performances to maintain isolation and prevent feedback.
 ■ when using stereo recording techniques such as
     • the X-Y pair, DIN, EBS, mid-side, NOS, ORTF, or RAI techniques.

• Use figure-8 microphones
 ■ to isolate off-axis sounds.
 ■ to isolate instruments and/or vocalists in close proximity.
 ■ to record a duet of singers facing each other.
 ■ when using stereo recording techniques such as
     • the Blumlein array, Faulkner array, Decca tree, or mid-side techniques.

    Microphone Placement

3-to-1 rule (to minimize phase problems)

• When two microphones are used to record a source, the microphones should be separated by at least three times the microphone-to-source distance.
• If you are recording two different sources, each microphone should be three times the distance from each other as the distance each mic is from its respective source.
• A distant microphone should be 3 times as far away from the source as a close microphone.

10-dB rule (to minimize phase problems)

• When using multiple microphones in close proximity, there should be at least a 10-dB signal difference between them.

    Control room acoustics

• Place the mixing desk on a the short walls, rather than a long wall.
• Target the listening position at 38% of the wall length from your front wall, but somewhere between 35% and 43%, avoiding nodal points (like 50% and 25%).
• The listening position and monitors should be placed in an equilateral triangle, with the apex just behind the listener's head.
• Monitors should be aimed at the listener at the height of the listener's ears.
• Absorption panels should be placed on the side walls centered halfway between the monitors and the listener.
• Place at least one bass trap in each front corner.

    Digital recording levels

• Record at 24 bits rather than 16 bits.
• Target on recording levels that average about -18 dBFS.
• Avoid any peaks higher than -6 dBFS.

    Effects/Plug-ins

• Insert effects (effects inserted directly into the track) are used with dynamic effects (such as compressors, limiters, and gates) and spectral effects (such as equalizers and enhancers).
• Send effect (effects inserted into an effects bus or aux track) are used with time-based effects (such as delays, echoes, and reverbs).

    Equalization

• When equalizing, attenuate (cut) frequencies rather than boost them.

    Impedance

• The input impedance of a device should be much higher than the impedance of source output.