Digital Audio Monitoring SET2008 V3

7/28/2019 Digital Audio Monitoring SET2008 V3

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Presented by Ing. Jess V. Osorio Lpez

Digital Audio Monitoring

SET2008


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Back to basics


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25 August 20083

Distortions

THD+N (Total Harmonic Distortion + Noise) IN=f

OUT=2f, 3f,.nf

IMD (Inter modulation distortion) IN=f1 & f2 OUT= f1+f2, f1-f2, f1*f2


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25 August 20084

If Sound Phase SameBetween Speakers

Phantom Source specific spot In Phase - Correlation is +1

If Sound Phase DifferentBetween Speakers

Phantom Source not specific,rather is smeared

Sounds origin over an area

More difference in phase, thewider the area

180 degrees out of phase,Correlation is -1

Phantom

Source

PhantomSource

Phase Differences and Correlation


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25 August 20085

Loudness


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Basic Monitoring


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25 August 20087

Amplitude, Phase and Correlation Monitoring Similar to analog, a need exists to monitor phasing of two or more digital

stereo pairs

Left display is in phase

Right display is out of phase

Monitoring


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25 August 20088

Meter Ballistics VU (Volume Unit) Meter

Shows average volume level Symmetric rise and fall times

Based on oldest analog dials

Peak Program Meter

Displays quasi-peak levels

Fast rise and slow fall time True Peak Meter

Displays actual peaks

Nearly instantaneous rise andfall times

Monitoring


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25 August 20089

Meter Scale dBFS

Decibels Full Scale where0dBFS is a sample of all1s

This is the default selection

Peak Program Level Default -8dBFS

User can change

Test Level Default -18dBFS

User can change

Monitoring


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25 August 200810

Monitoring


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25 August 200811

Monitoring


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25 August 200812

Monitoring Levels Monitoring with Bars

Meter Ballistics

Amplitude Levels

Clip (all 1s)

Over (-8dBFS)

Silence (-70dBFS)

Mute (all 0s) In Bar Displays

Unlocked

AES CRC Error

Silence

AES V Bit Mute

Monitoring


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Surround SoundMonitoring


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25 August 200814

Surround Sound Display

Allows visualization of interaction between multiple channels Left (L), Right (R), Center (C), Left Surround (Ls), Right Surround (Rs)

Show Dominant Sound

Correlation between channels

Phantom Phase Indicators

Linear or A Weighting Filters


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25 August 200815

Basics of the Surround Display


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25 August 200816

Phantom Source Indicators

Associated with each channelpair

Provides indication on thelocalization of the sound

White tic mark indicatescorrelated sound (+1)

Slightly Correlated (


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25 August 200817

Basic Display

Linear (RMS) Filter Linear relationship

between amplitude of

sound and display

A Weighting Filter Amplitude modulated by

frequency of sound relatedto human auditory

response

Correlation Bend outwards In-Phase

Straight Line 0 Correlation

Bend inwards Out-Phase


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25 August 200818

Example Displays


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MetadataMonitoring


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25 August 200820

Metadata Parameters 3Ds DialNorm

DialNorm Dialogue Normalization Uniform dialogue levels when decoding a Dolby stream.

Conveyed once per block (5ms)

Valid Range 1 to 31

Volume

SPL67dB

DialNorm25dB

Volume

SPL92dB

DialogueLevel

SPL 67dB

Program 1High Quality

Entertainment Program


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25 August 200821

Metadata Parameters 3Ds DialNorm

DialNorm Dialogue Normalization Uniform dialogue levels when decoding a Dolby stream.

Conveyed once per block (5ms)

Valid Range 1 to 31

Volume

SPL67dB

Volume

SPL82dB

DialogueLevel

SPL 67dB

Program 2Commercial

Message

DialNorm15dB


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25 August 200822

Metadata Parameters 3Ds Dynrng Example

DialNorm25dB

Full ScalePeak Level

0dB

Quiet Sound

Loud Sound

50dB BelowDialogue Level

(-75dB)

Dynrng -15dB

Dynrng +20dB

-75dB

0dB

-55dB

-15dB


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25 August 200823

Metadata Parameters 3Ds DownMix

Ability to hear all L C R Ls Rs in a stereo mix

(Lo Ro) Stereo DownMix

-3/-4.5/

-6 dB

-3/-6/0 dB

-3/-6/0 dB


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25 August 200824

Metadata Parameters 3Ds DownMix


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Audio structureReview


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25 August 200826

One Block = 192 Frames

One Frame = 2 Subframes

Start of Block indicated by Z Preamble

AES/EBU Data Structure (Review)


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25 August 200827

32 Bits/subframe

4 Preamble Bits, 24 Data Bits, 1 Validity,1 User, 1Channel Status & 1 Parity

Subframe

X Y

Frame

AES/EBU Frames & Subframes (Review)


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25 August 200828

Ancillary Data Format (Review)

SMPTE 291M Ancillary Data Packet and Space Formatting ADF Ancillary Data Flag (ADF) is a three-word header 000h 3FFh 3FFh

DID Data ID identifies the type of data packet DBN Data Block Number optional counter determines missing data

DC Data Count (DC) word indicating the size of data packet

Checksum Simple error detection


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25 August 200829

HD Audio Control Packet (Review)


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25 August 200830

Channel Status Mapping WFM7120


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LoudnessMonitoring


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25 August 200832

What is Loudness ?

Loudness is a subjective measure Different people perceive loudness differently

Loudness is primarily a psychological correlation of the physicalintensity of the audio signal.

Different techniques have been used to provide correlation ofthe overall loudness of the signal.

Different filters are used to adjust the models to perceivedloudness of the human ear.


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25 August 200833

Loudness Measurements Standards

IEC 61672-1 Electroacoustics Sound Level Meters

ITU 1770 Algorithms to measure audio program loudness and true-peak audio level

ITU 1771 Requirements of loudness and true-peak indicating meters


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25 August 200834

Configuring Loudness Measurement

Select Weighting Filter Linear, A Weighted, RLB

Select Duration Select Start & Stop Time

Leq, LAeq or L(RLB)

measurements Individual Channel Channel Pairs

Selected Channels

10 second Short Average

Infinite duration of Session Program Average

True Peak

Audio Level


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Audio Vide DelayMonitoring


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Summary


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25 August 200838

Summary FlexVu@Channel Status


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25 August 200839

Summary FlexVu@Error Status


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Documents

Digital Audio Monitoring SET2008 V3