Phase

Question 1

What are identical waveforms?

Answer 1

waveforms that are similar in every way, usually the outcome of duplication

Question 2

What are waveforms of the same event?

Answer 2

2 microphones capturing the same musical event

Question 3

What are dissimilar waves?

Answer 3

two different takes of any instrument, or otherwise completely different waveforms

Question 4

What are the three types of phase relationships between similar waveforms?

Answer 4

in phase/phase coherent, out of phase/phase shifted, and phase-inverted

Question 5

What does in-phase/phase coherent mean?

Answer 5

two similar waveforms start at exactly the same time

Question 6

What does out-of-phase/phase shifted mean?

Answer 6

waveforms start at different times

Question 7

What does phase-inverted mean?

Answer 7

both waveforms start at exactly the same time but the amplitude is inverted

Question 8

What is the Haas effect?

Answer 8

audible delay is only perceived if the time gap between two similar waveforms is greater than 30-40 milliseconds

Question 9

When is the Haas window, where one should start considering phase?

Answer 9

between 1-35 ms

Question 10

What can one expect if the time gap between two similar waveforms is less than 35 ms?

Answer 10

comb filtering

Question 11

What will happen if two similar waveforms are phase-inverted?

Answer 11

they will cancel and either cause level attenuation or cause silence

Question 12

What are three recording situations that could benefit from phase correction in mixdown?

Answer 12

1. ) top/bottom or front/back tracks; will capture opposite pressures
2. ) close mic and overheads; close mics could be out of phase with OH
3. ) mic and direct; mic will be slightly delayed with direct (gtr mic vs DI)

Question 13

What are four phase problems that can happen during mixdown?

Answer 13

1. ) lack of delay compensation
2. ) digital-to-analog conversion on outboard gear
3. ) very short delays
4. ) EQs; can cause group delay for a range of frequencies