Metering

Question 1

What do VU meters indicate?

What unit(s) of measurement do they use?

Are they fast or slow?

Answer 1

Slow, showing the RMS levels not the peak

uses the decibel scale but also has a second scale indicated in percentage of volume.

Question 2

What does the “VU” stand for in VU meter?

Answer 2

Volume unit

Question 3

What is the range of the dB scale in a VU meter?

Answer 3

Range: -20 dB VU to +3 dB VU

Question 4

How long does it take for a needle to reach 0 VU from -20 VU?

Answer 4

300 ms +/- 10%

Question 5

What is the standard overshoot on a VU meter?

Answer 5

1 - 1.5%

Question 6

What does the LED light indicate on a VU meter?

Answer 6

it’s a peak light, that light up when a predetermined transient level is detected (usually about 6-12 dB above the actual instrument)

Question 7

What type of meter is this?

Answer 7

BBC PPM meter

Question 8

In a PPM (BBC) meter, what does each mark represent?

Answer 8

each of the markings (1-7) represent a 4 dB change

with the exception of 0-1 which is a 6dB change

and 7-8, which is a 2dB change

Question 9

In a PPM meter, which marking corresponds to 0dBu?

Answer 9

Mark 4

Question 10

What does a Digital Peak Meter (DPM) display?

Answer 10

absolute maximum signal of the raw samples in the PCM signal for a given time

Question 11

What is the scale range of a DIN meter?

Answer 11

from - 50 dB to +50 dB

Question 12

In a DIN meter, what is the value of the 0 dB marking in dBu and in Volts RMS?

Answer 12

+6 dBu which is 1.55 Volts RMS

Question 13

In a DIN meter, where is the marking for the test level?

Answer 13

-9 dB

Question 14

In both Nordic and DIN PPM meters, where is full modulation on the meter and how many volts is “full modulation’?

Answer 14

Full modulation is at the edge of the red area

1.55 V RMS

Question 15

How many volts is the 0dB (test marking) on a Nordic PPM meter?

Answer 15

0.775 Volts RMS

Question 16

How are DPMs calibrated?

Answer 16

to 0dBFS or the max level that can be represented digitally in a given system

Question 17

What is a True-Peak Meter?

Answer 17

A digital peak meter with additional data pre-processing.

Question 18

How is the audio signal different in a True-Peak meter compared to a DPM?

Answer 18

TPM audio signal is up-sampled, usually by a factor of 4, to take intersample peaks into account.

Question 19

What scale and unit of measurement do true-peak meters use?

Answer 19

dBTP (decibels relative to full scale, measured as a true-peak value instead of dBFS.

dBTP and dBFS are identical except that dBTP may be larger than zero (full-scale) to indicate peaks.

Question 20

To comply with EBU R128, how loud should your normalised content be? What is the permitted deviation fromt eh target level?

Answer 20

Target Level: -23.0 LUFS

permitted deviation shall generally not exceed ±1.0 LU

Question 21

What do LU and LUFS stand for?

Which broadcasting body uses these as standard measuring units?

Answer 21

Loudness Unit

Loudness Unit, referenced to Full Scale

EBU R128 (European Broadcasting Union)

Question 22

What is the EBU R 128?

Answer 22

The European Broadcasting Union guideline for loudness normalization and permitted maximum level of audio signals, most recently revised in 2014.

Question 23

What are intersample peaks?

Answer 23

created as part of the digital to analogue conversion where the reconstruction of a sound wave exceeds 0dBFS to the true peak of the sound occurs between digital samples and thus gets “squared off”, creating distortion

Question 24

What does PPM stand for?

Answer 24

Peak Program Meter

Question 25

What meter is the most useful for the mastering process?

Answer 25

The Dorrough Loudness Meter

Question 26

What does the Dorrough Loudness Meter display?

What is it’s response time like?

Answer 26

diplays both average and peak elvels in a single readout with a very fast response time to accurately reflect incoming transients

Question 27

A “EBU Mode” meter offers which two scales, for the user to select?

Answer 27

EBU +9 scale and EBU +18 scale

Question 28

What is the range of EBU +9 scale?

Answer 28

-18.0 LU to +9.0 LU (-41.0 LUFS to -14.0 LUFS)

Question 29

What is the range of the EBU +18 scale?

Answer 29

-36.0 LU to +18.0 LU (-59.0 LUFS to -5.0 LUFS)