Week 28 - System Tuning

Question 1

What are the 3 “stages” at which we can EQ, and what does EQing “fix” at
each stage?

Answer 1

Channel EQ:
Fixes instrument and microphone

Bus EQ:
Fixes room or venue

System Processor:
Fixes Speaker enclosures

Question 2

What is the role of headphones in a live rig?

Answer 2

Having a common reference point no matter where you are

Question 3

What are some common EQ curves?

Answer 3

Flat EQ

Emphasis on speech: bell curve 90-100hz - 4-6kHz

Music: 80-100Hz boost 4-6kHz cut (rock show = wider bell curve at 80-100)

Music playback: Boosted lows, flat HF response

Question 4

How many channels of measurement does spectrum mode use and what functions does it provide?

Answer 4

Single Channel

RTA (Real Time Analyzer)

Spectrograph

Question 5

How many channels does transfer function use and what functions does it provide?

Answer 5

Dual Channel

Impulse response

Magnitude

Phase

Question 6

How is the frequency range divided in spectrum mode?

Answer 6

Octave, 1/3rd octave, 1/12 octave, 1/48 octave

Question 7

What are the practical application of a single channel RTA?

Answer 7

Feedback frequency selection

Room Frequency Response

Question 8

What are the practical applications of a single channel spectrograph

Answer 8

Feedback frequency selection

Troubleshooting

Question 9

What is dual channel measurement used for?

Answer 9

Dual Channel Measurement allows for a comparison of a systems frequency response by comparing the reference signal to the measurement signal

Input 1 is the measurement signal

Input 2 is the reference signal

Question 10

In SMAART, what is magnitude?

Answer 10

Magnitude is a comparison of the amplitude of the two signals being sent to the transfer engine

The magnitude window shows the gain/loss or deviation from the center 0DB line

Question 11

What are some practical applications of magnitude measurements?

Answer 11

Measuring the frequency response of a speaker/room

Measuring each driver (Passive Speakers)

Question 12

What is coherence, and what does it mean if it is low?

Answer 12

The coherence trace displays the stability of the transfer function over the frequency range. This is telling you if your measurement is accurate

If your coherence is low, you most likely have an issue with either reverberations or the signal to noise ratio of your measurement signal