Recording Techniques

Direct Injection:

• a DI box converts a signal at intrument level or line leval to microphone level
• a DI box converts an unbalanced signal to a balanced signal
• it gives a pure connection between the instrument and the audio interface
• Active DI boxes require phantom power, passive DI boxes do not
• often have a pad/attentuation switch
• often have a link output so signal can be split between interface and amp

Unbalanced:

• Two connector with two conductors each
• two wires inside cable: the signal wire and the ground wire
• example is guitar cable, identified by TS (tip-sleeve) 

Balanced:

• three conductors, three wires: two signal and a ground.
• Signal wires both send the signal, but one has polarity reversed
• this creates silence, but when audio gear flips the signal back it cancels out the noise
• giving a pure sound without noise
• Balanced cables are identified by TRS (tip-ring-sleeve)

• close miking involves placing a mic <30cm from the source
• the closer to the source, the higher the bass is (proximity effect)
• On and Off axis are used in recording guitar amps
• On axis gives a brighter sound and off axis dulls it a little
• this can also be used for other instruments

XY:

• two cardioid mics, small diaphragm condenser
• 90 degrees, not a huge stereo field
• need to be panned hard left and right
• few phase problems

Spaced Pair (AB):

• omnidirectional mics, 50cm+ apart
• greater ambience, poor mono compatability
• potential for huge phase problems
• need to be panned hard left and right

Mid-Side pair:

• 1 cardioid and 1 figure of 8 condenser as close as possible
• figure of 8 is at 90 degrees to source
• adjustable stereo image
• no phase problems