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LIVE AUDIO HANDBOOK
Best-practice hearing management for audio engineers
by Stephen Compton
PhD Candidate, MA, BA(Hons), Dip. Sound Engineering
LIVE AUDIO HANDBOOK
by Stephen Compton
PhD Candidate, MA, BA(Hons), Dip Sound Engineering
He that has an ear, let him hear ...
Quick Guide Version 2.0, March 2021
Best-practice hearing management for audio engineers
PhD Supervisors: Assoc. Prof. Rebecca Kelly-Campbell and Prof. Gregory O'Beirne
whakataukī (Maori Proverb)
Me he wai tā tieke
Like the saddleback sprinkling itself with water.
Good in moderation, but one can have too much of a good thing.
There is value in moderation but danger in excess.
CONTENTS
8 25
SECTION 1 SECTION 2
SPL and Loudness Are Not the Same Audio Engineer Culture and Practice
The appeal of ‘loud’ music The audio engineer
SPL vs Loudness 'Loud' and the audio engineer
Audio engineers on audio engineers.
An impossible job description?
Questions to ponder
9
Sound Measurements
34
Ear Sensitivity relating to ‘weighting’ curves
Measuring SPL (audio ‘volume’) SECTION 3
Metering terms The Ear
An overview of the audio engineer's most
valuable tool
12
Noise Standards
40
Standards development In-Ears and Earplugs
Quantifying risk and noise exposure calculations
Noise Standards, enforcement and responsibility In-ear monitoring management
Choosing and fitting earplugs
17 42
Hearing Management SECTION 4
Managing and reducing hearing fatigue References
Conditions that affect critical listening Memes
Engineering with hearing challenges The author
Music-related hearing statistics Contacts
FOREWORD
The live-sound 'experience' is powerful,
connecting feelings, memories and people:
physically, emotionally, socially and spiritually.
Within the live-sound 'experience', They are a gatekeeper, directing
the audio engineer stands in a the flow, by which the 'experience'
pivotal and rarely understood is shared.
role as a creative multitasker and
problem solver. Why do audio engineers make the
choices they do?
From the stage, the talent may
provide the source audio, but it Behind the production of this
is the audio engineer that makes handbook is a study documenting
crucial decisions that weigh up all audio engineering culture, working 01
contributing sonic influences, and alongside audio engineers to Author Stephen Compton
the opinions and expectations of improve the live-sound ‘experience’
others. for all participants.
- Stephen Compton 02
Selwyn Sounds
- Christchurch, NZ, 2018
(SC FoH Tech)
“
“My job was to get a balance and
be invisible, to be a servant of the
music and provide the technology
to establish an emotional connec-
tion between the musicians and
audience.”
02 – Bryan Bell, FOH engineer
Page 6 | Live Audio Handbook
03
Mix Position Miss
Saigon,Showbiz, Christchurch,
NZ, 2019 (SC Sound Op)
04
Lauren Daigle, 2019,
03 Christchurch, NZ
This Quick Guide aims to:
• present an overview of the audio engineer's most essential and often
misunderstood tools,
• provide practical steps for audio engineers to prepare for critical listening,
• promote hearing longevity, and
• provoke discussions that improve live-sound practice.
“
“As a practitioner of this craft you
have to simultaneously understand
your equipment and your input
- meaning the artist on stage or
whatever the content is - as well
as who is listening to the results of
your work.”
- David Scheirman, mix engineer
system consultant 04
Live Audio Handbook | Page 7
SECTION 1
THE APPEAL OF 'LOUD' MUSIC 12 43 50
People react to loud sounds physically and emotionally in different ways.
Loud music activates a sense of 'touch without being touched'. High-
intensity sound waves ('loud' sounds) cause larger vibrations within the
inner ear than quieter sounds, which leads to a higher rate of nerve impulses
reaching the brain. Louder sounds stimulate a larger number of hair cells. 48
Auditory adaption occurs when people associate enjoyable times with loud
music and in the mind of the individual, enjoyable times and loud music
become linked.
To the listener, increases in 'volume' can soothe and mask internal thoughts,
can motivate, stimulate arousal, draw people together, encourage physical
movement and enhance a sense of personal identity. Both in the ear's
balance and sensory organs and the body cavity, loud sounds can provide
pleasurable vibrations. The music itself can contain an 'emotional contagion'
where the listener responds to a similar emotion as the performer, can
conjure memories or visual imagery, and facilitate social cohesion or
intimacy. Sudden or dissonant sounds can also induce a reflex important
for survival.
05
SPL AND LOUDNESS
Throughout this handbook,
Are Not the Same Thing 39
SPL (Sound Pressure Level)
will be regarded as being SPL (Sound Pressure Level measured in dB) can be
measured using a sound meter.
synonymous with the commonly
used term audio 'volume'. Sound Pressure (in pascals) within a space can
differ, dependent on location and the distance from
the source. Doubling the distance from the source
measures a 6 dB reduction.
06 Sound Power (in watts) - is the rate at which sound
05
energy is emitted per unit time. Adding two of the
Line Array, Selwyn Sounds 2020 same sound waves together (coherent signals) results
06 in a 6 dB increase in sound power. Adding two different
(incohertent) signals of the same power results in a
Apple Airpods Pro 3 dB increase. Two different electric guitarists playing
at 85dB each in the same space: 85 + 85 = 88 dB.
“
Sound Intensity is calculated by sound power (watts)
per unit area.
“When you turn up the kick in a Loudness is the psychological description of the
large arena with a massive PA, it’s magnitude of auditory sensation corresponding most
something you never forget. Once closely to the physical measure of sound intensity.
you’ve mixed, you always want to The listener may describe higher limits as being
mix.” uncomfortable, but the reaction may not necessarily
- Dave Natale, FOH engineer
be related to the SPL value. Perceptually, a 10 dB
increase is recognised as sounding twice as loud.
Page 8 | Live Audio Handbook
EAR SENSITIVITY RELATING TO ‘WEIGHTED’ CURVES
Equal Loudness Contours A and C Weighted Curves
Sound Intensity, dB
dB, Attenuation
07 08
Frequency, Hertz Frequency, Hertz
Human hearing is most sensitive Audio measurement weighted A-weighting - 1 kHz at 40 dB.
to frequencies that benefit speech curves (fig.08) aim to adjust any C-weighting - 1 kHz at 100 dB.
and communication. The equal SPL measurements to the human Z-weighting - flat response.
loudness contours graph (fig.07) experience at various levels of
demonstrates this. To hear the stimulation. Weightings are an
sibilant frequencies within the approximate inverse of the equal
spoken word around 4 kHz, loudness curves where each
where we hear ‘s’ and ‘t’, less weighting relates to a 1 kHz tone
SPL is required than for other at the SPL values shown. 29
frequencies.
07
Equal Loudness Contours
• A, C and Z-weightings are most commonly used in
08
the audio industry.
• Despite the A-weighted scale being the most common live SPL A and C-Weighted Curves
measurement, C-weightings more accurately represent the ear
sensitivity at the higher SPLs commonly reached at live-sound
events.
• The A-weighted curve is only beneficial below 70 dB.
• A-weighting does not account for low-frequency energy which
can cause high-frequency damage. 17 28 45
“
• Z-weightings more accurately measure SPL peaks than A or
C-weighting.
“Sonic excellence occurs when you
capitalize on the best opportuni-
ties for reinforcing the sound that’s
already being created onstage. Do
that, and then you don’t have to
work so hard the rest of the time.”
- Brett “Scoop” Blanden, FOH engi-
neer
Live Audio Handbook | Page 9
MEASURING SPL
Sometimes noise and music can feel like the same thing! 22
Measuring the SPL and the effects of noise and music commonly requires different considerations.
As humans, we generally react differently to noise Measuring the intensity of sound
than to music. Noise is as an often uncontrolled, vibrations, SPL, requires metering
less constrained, statistically random and commonly devices like those shown in fig.09,
unwanted sound. In contrast, music is a dynamic, 10 and 11.
multifaceted, and multisensory phenomenon that
is 'experienced'. Music contains informationally rich Many types of machinery produce
events that cannot be reduced to simple perceptual a consistent level of ‘noise’.
dimensions of pitch and rhythm. 43 This consistency of SPL can be
measured using a simple sound
Despite being at similar SPL levels, noise, pleasant meter (fig.10) to determine the
musical sounds and unpleasant musical sounds each average level and peak.
can yield different effects on our physical hearing
mechanisms and our emotional responses.2 3 10 16 25 29 41 The SPL of music is not consistent
and varies with every beat, bar,
song and act. Establishing the
average SPL (LEQ) for music
requires a sound meter capable
of recording an average SPL over
time.
Meters that record LEQ (Average
Level) are often more expensive
(fig.11); however, the free iOS
NIOSH App (fig.09), is effective in
measuring instantaneous SPL, LEQ
and exposure (dose).
09 10 11
“
“Tom (Petty) and the band have
taught me over time that there’s
just as much skill in revealing
something as there is in bringing
something up. It’s not always about
09
10
iOS NiOSH APP. Monitor SPL, LEQ
and Dose
Inexpensive SPL meter.
louder, it might be a matter of pull- Instantaneous SPL only
ing something back so something
11
else shines through.”
- Robert Scovill, FOH engineer SPL meter capable of recording
Instantaneous SPL, LEQ, PEAK,
frequency spectrum data, delay
times, reverberation times,
audio and more
Page 10 | Live Audio HandbookMETERING TERMS
LAEQ and LCPEAK
L = Level
A = A-weighted LEQ = Average Level (constant equivalent)
C = C-weighted PEAK/MAX = peak/maximum level
Decibel (dB) Relative measure of the level of sound.
Dose Average SPL (audio 'volume') over the time exposed.
Exchange rate For every increase of the exchange rate (e.g. 3 dB),
the allowable exposure time is halved.
L fast Used to show varying SPL over a 125 ms time
constant.
L slow Used to smooth the SPL readings to make it easier to
read over an approximate 1 second time constant.
LAEQ Level - A-weighted - constant equivalent (average).
For use over the whole performance.
LAEQ5" Level - A-weighted - constant equivalent (average)
over 5 minutes. For use over the period of a song.
LAEQ30" Level - A-weighted - constant equivalent (average)
over 30 minutes.For use over several songs to allow
the engineer to make changes that could impact SPL
readings over a performance.
LAEQ85 Level - A-weighted - constant equivalent (average)
of 85 dB.
LAEQ8h Level - A-weighted - constant equivalent (average)
over 8 hours.
Metering Class Sound metering equipment accuracy as defined by
international standards: IEC 61672-1:2002 (or BS
EN61672-1:2003).
Class 1 is a standard for equipment taking accurate
calibrated measurments.
Class 2 is a standard for equipment taking calibrated,
measurements within an accepted higher tolerance
than that of Class 1 devices.
SPL Sound Pressure Level, commonly referred to as
audio ‘volume’.
TWA Time weighted average.
12
12 Theatre Tools (SC Sound Op)
“
“Two hard-earned observations:
1) No matter how much I yell at
the crew, it never makes it sound
better;
2) If I act like there’s a huge prob-
lem, people will know there’s a
huge problem.”
- Dave Rat, FOH engineer,
Rat Sound
Live Audio Handbook | Page 11NOISE STANDARDS
A Brief History of Noise Standards Development 1 18 29
Noise standards came out of a desire to protect individuals primarily from
hearing damage that would affect communication.
The United States began formalising Hearing Conservation regulations in the
late 1960s. Internationally since 1969, noise standard developments have
weighed the acceptable levels of risk against the cost to implement a safer
practice.
Noise standard calculations relate to the individual's exposure to sound levels
over the course of a 40-hour working week through their working life. While
many countries choose to calculate based solely on exposure times, the USA
OSHA standards factor in taking breaks away from the noise.
Definitive data on human sound exposure tolerances are difficult to obtain
without risking research participant’s permanent hearing.
While the effect that noise exposure levels have on hearing is well documented,
the determination of responsibility for managing and facilitating hearing
protection for live-sound personnel differs internationally.
13
“
“At the end of the day, the guy sit-
ting in the third row doesn’t care
how long it took to hang the PA, or
how light weight it is. He just wants
it to sound good, and so do I.”
13
Def Leppard 2018, Auckland, NZ
- Kevin Margolin, co-founder,
Atomic Professional Audio
Page 12 | Live Audio HandbookQUANTIFYING RISK
Any human activity involves an element of risk.
The exposure to sounds over 70 dB presents some risk to hearing function.
The ambient sound levels of many city streets, public spaces, and transportation
and the prevalent use of personal music devices, commonly exceed 70 dB. 18
22 51
The following table estimates the risk associated with average 'volume
levels' over a given exposure time.
RISK COMPARISON
29
when exposure is similar over a 40 hour week, over a working career
Workplace NZ,
World Health Organisation,
and many other countries OSHA (USA)
8% risk 25% risk
(to hearing function) (to hearing function)
Average Exposure Exchange Average Exposure Exchange
SPL Time Rate SPL Time Rate
85 dBA 8 hr 3 dB 90 dBA 8 hr 5 dB
Exchange rate: for every Exchange rate: for every
3 dB increase the recommended 5 dB increase the recommended
exposure time limit halves. exposure time limit halves.
14
Average Level Exposure Time
85 dBA 8 hrs The 2021 World Health
88 dBA 4 hrs Organisation's World Report
on Hearing recommends that
91 dBA 2 hrs to avoid irreversible noise-
94 dBA 1 hr induced hearing loss, exposure
to loud sounds through leisure
97 dBA 30 mins
noise and personal audio
100 dBA 15 mins devices should be limited to 80
103 dBA 7.5 mins dBA over 40 hours in a week
for adults and 75 dBA over 40
106 dBA 3.7 mins hours in a week for sensitive
109 dBA 1.8 mins users, e.g. children. 22 52
14
Noise Standard Risk
Comparisons. “
“There will always be a desire for
good sound and a general lack of
understanding in attaining it. So not
everybody will just be able to throw
together a sound system with any sort
of good or even mediocre results.”
- Jim Long, Electro-Voice
Live Audio Handbook | Page 13NZ NOISE STANDARDS
Safety Standards protect individuals and the environment. In New Zealand, more than one regulation refers
to noise. The 1995 Health and Safety in Employment Regulations and Worksafe NZ provide general noise
exposure recommendations. Section 322 and 326 of the Christchurch City Council Resource Management Act
are shown here as examples of local NZ council regulations that refer to noise.
Health and Safety and Worksafe NZ 35 Worksafe New Zealand
The 1995 Health and Safety in Employment Regulations PCBU (Persons Conducting a Business) primary duty
in New Zealand state that employers should take all of care: 46
reasonable steps to ensure that employees are not • is for workers and non-workers (other persons).
consistently exposed to noise above 85 dB for an Section 22 lists the relevant health and safety
8-hour working day, whether or not the employee is matters they are to weigh.
wearing a hearing protection device (e.g. earmuffs or • Section 23 lists the loss of a bodily function as a
earplugs). Health & Safety Regulations set a maximum category where PCBUs must protect.
peak noise level limit of 140 dB.
Local Council Plan: 13 42
The public, customers and attendees are included in • Christchurch: CCC Resource Management Act
Worksafe NZ standards as 'other persons'. details in Section 326 that excessive noise is
any noise under human control ... that may
Health and Safety at Work Act 2015 (22-25): 46 … interfere with the peace and comfort and
Employers ... have a duty to weigh up the likelihood convenience of any person.
or risk concerning the degree of harm from a hazard/ • Section 322 mentions an abatement notice
risk that they ought to know ... resulting in the loss of may be served on any person … if an activity
a bodily function. is likely to be noxious, dangerous, offensive
or objectionable … to the extent that it
Section 6 of the HSE Act requires employers to take all has an adverse effect on the environment.
practicable steps to ensure the safety of employees
at work and to provide a safe working environment. 15
Lauren Daigle 2020, Christchurch, NZ
Points to note on NZ Regulations: 29 46
• The Health and Safety Work Act 2015 should recognise hearing as a 'bodily function'.
• The local Christchurch City Council Plan contains some ambiguity in quantifying what excessive noise
is, and seems concerned with possible adverse effects to the environment over any adverse effects on
the health and safety of individuals.
• LAEQ85 over 8 hours still contains an 8% risk of damage.
• Acoustic shock (symptoms a person may experience after hearing unexpected or loud sounds) and
instantaneous hearing loss can occur at a lower SPL than LCPEAK140.
“
“Whatever sounds good on a par-
ticular instrument on a particular
day, we move forward with that.”
- George Cowan, FOH engineer
15
Page 14 | Live Audio Handbook16
NASDA Hair Ashburton, NZ
(SC Sound Design and Op)
17
Trade Show 2018,
16 Guangzhou China
17
INTERNATIONAL NOISE STANDARDS
Noise standards vary between countries.
Most countries allow higher noise exposure levels than the World Health
Organisation's recommendations. The following examples demonstrate
a few of differences between international noise standards:
Brussels
Brussels has three different categories of sound levels:
1 LAEQ15" forENFORCEMENT AND RESPONSIBILITY
18
New Zealand: Internationally:
• Local City Councils monitor SPL at the Internationally, the enforcement of noise
event/public boundaries to limit the standards varies significantly, where some
event's interference on the peace and impose financial penalties for exceeding
comfort of neighbours and not within local standards.
the event boundary.
• There is ambiguity on what constitutes
‘excessive noise’, In 2018, a UK landmark High Court
• There is ambiguity surrounding the case, found that those responsible for
PCBU's 'weighing up all relevant oversight at the UK Royal Opera House,
matters' with respect to SPL and hearing were at least partly responsible for a viola
safety at events, player’s hyperacusis (hypersensitivity to
• In NZ, any litigation regarding noise noise). The damage was caused during
control is to be funded by the the rehearsal of an orchestral piece that
complainant, and acoustically peaked at 137 dB. 11
• Identifying the responsibility for any
participant hearing damage is difficult This legal precedent acknowledges
to connect to a particular event, as that the responsibility for personal
the participant’s total noise exposure hearing protection IS shared with
also includes the contribution of
live-performance management.
personal audio devices, workplace and
environmental noise.
While the 2021 World Health Organisations
“
World Report on Hearing seems to favour
legislative means to regulate sound
exposure at events, a 2020 international
“This business is not for the
audio engineer survey reveals this method
squeamish. You can get squashed
is one of their least favoured hearing
like a bug, but if you can survive it,
you can make a comfortable living, management solutions. 52 53
you can work half the year. You’ve
just got to pay attention and stay
18
out of jail.”
- Jim “Redford” Sanders, mix engi- Hillsong Manhattan, 2018,
neer NY, USA
Page 16 | Live Audio HandbookHEARING MANAGEMENT
Hearing Management benefits the audio engineer by:
• maximising their critical listening ability,
• avoiding issues that hearing damage causes, and by
• reducing or preventing harm to others.
19
19
Toto, Hagley Park, 2018,
Christchurch, NZ “
“If something happens on stage and
you’re working for the President of
the United States, you want to walk
calmly, with authority, and go up
and fix it. You don’t want to run, be-
cause the Secret Service will shoot
you in the ass.”
- Mike Bourne, All-Star Audio Sys-
tems
Live Audio Handbook | Page 17REDUCING HEARING FATIGUE (TTS)
Hearing fatigue is a reduced response to some audio frequencies and is known as a
22
temporary threshold shift (TTS). TTS can lead to a permanent threshold shift (PTS).
When a traumatic occurrence causes hearing loss, the threshold shift classification
22
is a noise-induced hearing loss (NIHL), or music-induced hearing loss (MIHL).
Hearing/listener fatigue (TTS): 40 Managing Hearing Fatigue and
Preparing to Mix
• occurs from listening to audio
at high volumes, To minimise hearing fatigue and
• is affected by elevated body prepare for critical listening: 20
temperatures, as in those • schedule rest periods without
who exercise, earplugs or headphones,
• occurs faster when the • wear hearing protection
listener has some prior on planes and other noisy
hearing damage, vehicles or environments, and
• when the hair cells that • minimise the time exposed to 20
translate a particular high SPL.
20
frequency die, the brain
needs to work harder Can we prepare for high 'Hearing Fatigue?'
to process incoming sound pressure levels?
information, making reaction
times slower, Some would say there is no way
• may increase for in-ear to prepare hearing mechanisms
monitor (IEM) wearers and for loud sounds without hearing
monitor engineers who wear protection. Sound contains a
headphones or earphones. potential for damage.
Blocking the ear canal and
creating a pressure chamber We could liken loud sounds
dampens sounds, making to putting our hand over a
them appear to be not as flame. Our hand is not naturally
“
loud as they are, and designed to cope with being over
• artefacts left by audio an open flame. If our hand is far
processing (e.g. high enough away or we only have
compression), or distortion exposure for an extremely short “To me the greatest compliment a
also increase the brain time, we may be safe enough. By band can pay you is to rehire you.”
processing required. wearing appropriate protection, - Deb Hutchins, monitor engineer
we can also be exposed for
longer periods.
Page 18 | Live Audio HandbookOTHER HEARING CONDITIONS
THAT AFFECT CRITICAL LISTENING
A healthy auditory pathway provides the audio engineer
with the best opportunity to listen critically,
which in turn guides their choices.
Other conditions affecting critical listening can include:
• acoustic shock - damage to the auditory system caused by high There is currently no way
sound pressure and exposure, 22 to precisely predict the
• tinnitus - (more details on the next page), susceptibility to damage
• hair cell damage causing a loss in sensitivity, often beginning that loud sounds pose to a
around 4k and then spreading to adjacent frequencies, particular person.
• hyperacusis - a hypersensitivity to sound where quiet sounds
appear loud, 41
• diplacusis - hearing one tone as two tones of different frequencies
in each ear, 41
• distortion of tones, 41
• ruptured eardrum,
• presbyacusis - age-related high-frequency loss, where the
perception of higher frequencies reduce as we age, 14 48
• PTS - permanent threshold shift - which is a permanent loss of
hearing at particular frequencies, 22
• Meniere’s disease - is an inner ear disease, causing vertigo,
dizziness, balance issues, tinnitus and pitch perception, 8 48
• physiological changes affecting auditory perception - can be a
reduced sensitivity to weak sounds, or 'loudness recruitment'
where the sensitivity to some loud sounds increases, the effects of
which reduces the accepted dynamic range and may also affect the
ability to perceive pitch accurately, 34 and 21
• disruption to the auditory pathway between the cochlear hair Theatre Opening Performance
cells and the brain which can be caused by long-term noise Brisbane, Australia (SC Tech)
“
exposure. 25
21
“I’ve done everything from schlep-
ping gear, to setting it up, to
designing it, to mixing on it. I like it
all. It’s a good day’s work.”
- Phil Scobee, mix engineer/system
consultant
Live Audio Handbook | Page 19TINNITUS
5 22 41
22
Tinnitus is the term used for a noise The risk of tinnitus is twice as high
that is heard but does not come in musicians compared to the
from an outside source. Tinnitus general population, with 50% of
is often described as a ‘ringing in professional musicians reporting
the ears’ but can be experienced tinnitus. 40 In one investigation,
in other ways, like a buzzing or more than two-thirds of live-sound
hissing, waves, cicadas or even a respondents reported tinnitus
thumping sound. It can be faint as the most common effect of
or loud, constant or occasional, changes in their hearing, followed
steady or pulsing. The effects can by a loss of response to specific
range from not bothersome to frequencies. 44
very annoying. Tinnitus is more
noticeable in quiet times, at night Tinnitus affects:
or when tired or stressed. • 34% of audio engineers have reported experiencing tinnitus53
• 54% of percussionists, 41
• 57.6% of professionals musicians versus 44.2% of amateurs, 41
• 60% of violinists in one ear only, 41 and
• 24(49)-30% of orchestra musicians who find tinnitus bothersome
and 6% highly bothersome.
Tinnitus masks audio frequencies.
23
22
Ear Trumpet - Tinnitus
23
Jimmy Barnes, Selwyn Sounds,
Christchurch, NZ, 2018
(SC FoH Tech)
“
“They’re just tools, not a magic
safety net. No single person who
wants to truly succeed as a mixer
can do it by relying on a machine.” -
Wayne Pauley, mix engineer
Page 20 | Live Audio Handbook24
WHAT COULD A TYPICAL
AUDIO ENGINEER'S
HEARING LOOK/SOUND LIKE?
In one study, sixty-nine pop musicians, four
disk-jockeys, four managers, and six live-sound
engineers, had their hearing tested. 7
From the participants mentioned above, fig.24 is an
audiologist's pure-tone audiogram displaying their
average hearing response. 7
An individual with this shaped audiogram is said to 25
have ‘MILD’ hearing loss. An earlier study amongst
audio engineers found that 10% of the participants
demonstrated a moderate to severe hearing loss at
around 4000 Hz. 7 This audiogram would concur with
that previous study.
In a more audio engineer recognisable format,
the fig.25 parametric EQ curve demonstrates the
frequency loss represented by the audiogram in
fig.24. The fig.26 curve illustrates the frequency
compensation required to make up for the loss.
How would implementing the 'MILD' hearing loss
EQ curves in fig.25 and 26 affect a given sound?
Could these examples explain why some
audio engineer's 'mixes' contain significant
high-frequency content?
26
“
“I look at it this way. There’s 24 hours
in the day, and sometimes 22 of them
can suck pretty good. However, when
the lights go down, and the people
stand up and start screaming, I get two
24
25
Averaged audiogram from live-sound participants 7
Audiogram viewed as an EQ curve
26
hours that make it all worth it.”
- Jim “Redford” Sanders, FOH engineer Audiogram EQ with frequency-loss compensated
Live Audio Handbook | Page 21AUDIO ENGINEERING WITH SOME HEARING DAMAGE
Within the hearing process, the human brain consumes significant energy to convert and process
audio vibrations. 2 An impaired hearing will affect the audio engineer decision-making process.
Despite some hearing loss, audio engineers may still be able to function, adapting any physical changes as if
navigating in a new city or location, relying on other navigation techniques and signposts. A sound engineer
may still have abilities that make sense of sound better than people with less damage. 2 27 An experienced
engineer can also retain valuable motor, problem-solving and interpersonal skills that are more advanced than
the novice, even when some frequency discrimination is compromised.
An impaired audio engineer
may be assisted by:
• a spectrum analyser (e.g.
Smaart fig.25) which can
provide visual cues on
frequency content that has
been masked or is missing,
• a trusted colleague with fresh,
undamaged hearing acting as
'second ears', and
• critical listening to high-
quality and related-to-the-
performance audio material,
where the engineer can
establish a reference point for
27 their 'mix'.
APART FROM SPL, CAN THE 'MIX'
AFFECT HEARING LONGEVITY?
27
Rational Acoustics's Smaart The effects of noise and music on hearing and any potential
Spectrum Analyser damage is different, perhaps because music provides less
stress than industrial noise. 16
At similar levels, unpleasant sounds are more likely than
pleasant sounds to cause temporary threshold shifts (TTS)
and have a negative impact on health. 2 3 10 23 25 41 47
“
These findings put greater onus on the ability of the audio
engineer to make the mix ‘pleasant’ to maximise the
A talented sound engineer can get a listener’s health and their ‘experience’.
better-than-average sound from an
average sound system, while a less Conversely, the potentially most dangerous stimuli are
talented sound engineer can achieve perhaps the least bothersome as we allow ourselves to
a lesser-than-average result from a be exposed to higher levels of music for more extended
superb sound system.
amounts of time because we find it less disturbing than
- Tony Edwards, Director, Sound Choice
noise. 6
Pro Audio NZ Ltd
Page 22 | Live Audio HandbookFACTS, STATISTICS AND EFFECTS
WITHIN THE MUSIC INDUSTRY
18
The audio engineer is a musican whose instrument is their mixing technology. The following hearing
management statistics relate to musicians and music listeners.
• 1.1 billion young people have some form of Asymmetry
music-induced hearing loss. 51
• Over 50% of professional musicians have hearing Male jazz or rock musicians that play in amplified
loss, mostly around 4-6 kHz. 41 sound environments report significantly weaker
• Musicians are four times as likely to experience hearing thresholds in their left ear. Amongst classical
noise-induced hearing loss than non-musicians.24 orchestral musicians, violinists, violists and drummers
• 68-74% of pop/rock/jazz musicians have hearing may have reduced hearing ability in their left ear, 36
disorders. 24 41 while flute and piccolo players may have reduced
• Percussionists and brass players have the worst hearing ability in the right ear. A flautist may still have
hearing thresholds of all musicians. 24 reduced hearing ability in their left ear due to the
• Hearing loss tends to be more prevalent in male location of trumpet players on their left side. 41
musicians than female musicians.
• Diplacusis is present in 18% of musicians, 5%
in orchestra players. 41 49 Diplacusis produces a
notably different perception of a single frequency
tone in the two ears of up to 15-20%. A 200 Hz
tone in one ear may sound like 240 Hz in the
other ear.
• 24% of musicians, 12% being orchestra players,
report a distortion of tones, overtones and
harmonics where these appear unclear, fuzzy or
out of tune. 41 49
• 39-79% of musicians report hyperacusis. Women
report a higher rate than men, compared to 15%
of the general population. 24 41 28
GOOD NEWS!!! 50% of musicians and 43% of audio engineers have
found ways to work in a noisy industry without experiencing hearing damage!
“
"How [do you] tell a loved one they’re coiling cables wrong?"
- Tom K
28
Les Miserable, Showbiz Chch,
Christchurch, NZ, 2018
(SC Sound Op),
Live Audio Handbook | Page 23OTHER HEALTH AND SOCIAL EFFECTS
15
While not all hearing damage is the result of acoustic trauma, the effects of reduced hearing function are also
not just restricted to hearing processes and include:
• headaches, • depression, • social isolation,
• nausea, • insomnia, • fluttering in the ear, 32
• balance issues, • declination of cognitive • effects on concentration and
• anxiety, ability, morale, and
• hypersensitivity, • reduced ability to perform • mitochondrial DNA damage 31
• fatigue, musically,
MASKED RECOVERY
30
In the days following a concert,
our hearing may seem to have
recovered from any threshold
shift, where the shift is no longer
significant. What may take longer
to recover from, possibly over a
period of a week or two, is the
ability to perceive words in noise.
FINANCIAL COST
15 52
The estimated total financial cost
of hearing loss within NZ in 2016
is NZ$4.9 billion, with the cost
to the NZ economy at NZ$957.3
million. These figures present a
cost to each New Zealander of
NZ$5556 in contributions toward
assisting individuals with hearing 29
loss issues.
Of persons aged 12–35, 50% are at risk of hearing loss due to exposure to unsafe levels of sounds in
recreational settings. 1.5 billion people experience hearing loss, and this figure could grow to 2.5 billion by
2050. Without hearing loss intervention, the global economy is estimated to lose close to one trillion dollars
each year. WHO estimates that investing in ear care and hearing management could bring a return of sixteen
dollars for every dollar spent.52
“
“Some people see every other company in the world as
competition, as in, ‘they’re my enemy.’ But I see them
as trying to live their dreams like I’m living mine.”
- Mike Bourne, owner, All-Star Audio Systems
29
Prince, 2016, Brisbane, Australia
Page 24 | Live Audio HandbookSECTION 2
The content in SECTION 2 is from a yet to be published research into 'Audio Engineer Choice, Mixing Hearing
Management with Live Sound Culture'. The following data is compiled from an international audio engineering
culture survey conducted between April and May 2020 as part of the author's PhD study with 98 participants. 15% of
respondents are volunteer audio engineers, 32% are professional engineers, 53% are both volunteer and professional
engineers. 38% had < 20 years experience, 5% had 16-20 years, 13% had 11-13 years, and 25% had 6-10 years. 52
AUDIO ENGINEER CULTURE AND PRACTICE
An ongoing study as part of PhD Research 53
Musicianship:
75% of audio engineers play an instrument, perform, Live-Sound Hearing Management
compose or arrange music. 77.9% of audio engineers believe the live-sound
industry should make a concerted
Education: push to address noise exposure, to
improve hearing safety,and hearing
58% of audio engineers have had some formal audio longevity of participants,
engineer education. Of those who have had formal 18.2% of audio engineers believe it is a good idea
education he highest qualification these engineers but doubt it is possible,
have attained is: 10.4% of audio engineers believe the live-sound
• 31% Certificate / Diploma, industry could not be reconditioned to a
• 46% Degree, safer lower average SPL over time.
• 11% Honours / Masters,
• 4% PhD,
• 7.5% Other.
Personal Hearing:
91% of audio engineers have considered the impact
of hearing impairment. 17% of audio engineers have
never had a hearing test. 54% of audio engineers
reported they have noticed challenges to personal
hearing that could affect critical listening.
Of these:
• 61% High-frequency loss,
• 57% Tinnitus,
• 4% Diplacusis,
• 40% Reduced ability to hear speech in 30
noisey environments,
• 44% Age-related high-frequency loss,
• 21% Other hearing issues.
30
Noise Exposure: Discreet microphone technique
(Shure beta 89a)
“
The number of days per week audio engineer's are
exposed to levels beyond WHO recommendations :
• 0 days - 24%, • 4 days - 11%,
• 1 day - 32%, • 5 days - 3%, “If you want to make a million in audio, you know how
• 2 days - 11%, • 6 days - 1%, you do it? Start with two million.”
• 3 days - 14%, • 7 days - 4%. - Ryan Jenkins, owner, Arizona Concert Sound Solutions
Live Audio Handbook | Page 25“
“The rules of touring are simple. Show up, do
your job well, and don’t be a jerk. You’re living
in a submarine with a bunch of other people.
You’ve got to be enjoyable to be around.”
- Jamie Anderson, Rational Acoustics
'LOUD' AND THE AUDIO ENGINEER
Audio engineer beliefs on the appeal of 'loud':
The Sound
• Sounds 'better', clearer, more punchy and
energetic.
• Lower volumes are perceived to have less 'life'.
• At higher SPL, the ear response curve flattens,
making the audio sound 'better'.
• Despite perceptions that loud is better, maybe it
doesn't have to be 'loud' to sound good.
The Physical
• Arouses and affects the body physically, more
than just hearing mechanisms, particularly with
low-frequencies.
• Helps to cause pleasurable sensations from
natural bodily chemicals and processes.
• At higher SPLs, people can hear and feel the
parts of music, particularly bass, that may not be
31 heard on small portable and home devices.
The Connection
31
'Loud!' • Participants feel connected to the music, the
artist, and others present.
32
• Creates an immersive event where listeners feel
10cc, Selwyn Sounds enveloped by the sound, providing an 'escape' to
Christchurch, NZ, 2020 'get lost' in or to feel part of something 'big'.
(SC Guitar Tech)
• Reduces distractions and helps people to focus
on the music/event. For performers, high SPL
32
ensures their sound is foremost in an audience's
mind.
• Interactions between participants amidst loud
sounds require people to be more energetic to
be heard, adding to the 'vibe'.
• Drowns out the singing of attendees, and each
can sing along without their own voice being
heard.
• May be more appealing to particular groups,
genres and ages.
• Triggers emotions.
• May have an addictive side.
Page 26 | Live Audio Handbook‘Loud’ can be a subjective term and does not
necessarily reflect a potentially damaging SPL.
Audio engineers describe what they believe
‘loud’ may mean:
• the performance is louder than the sounds
individuals hear in their everyday life,
• the lyrics cannot be heard over the music,
• attendees struggle to talk to each other over the
performance,
• the style or content is not favourable,
• there are issues with the performer’s pitch, timing
or rhythm,
• the listener has unrealistic expectations of the 33
event sound,
• the SPL is not appropriate for a particular genre,
• the frequency content of the mix is not balanced. NASDA - Curtains, Christchurch, NZ,
33 2019
A well-balanced ‘mix’ may subjectively feel less 'loud'
(SC Sound Designer and Op)
than a quieter and less-balanced ‘mix’,
• the SPL may obscure or mask the listener's ability to hear
and interpret all the intended sounds,
• compression or distortion artefacts fatigue the listener,
• there is minimal dynamic variation where the ear can rest,
• one sound source cannot be heard over another,
• the room acoustic or stage sound bleed adversely affects the front-of-house mix,
• the quality of the equipment or the lack of system optimisation process has a detrimental effect on
the sound quality,
• the listener was not in an ideal location with respect to the sound source and the PA,
• that hearing damage has impacted the individual's perception. 'Loudness recruitment', may affect the
listener's tolerance to increasing loudness over-proportionally. If the damage is in one ear only, the
perceived loudness grows faster in the normal ear until the same perceived loudness in both, 39 44
• an audience member may mention the sound is too loud as a means of 'control', and
• that "you can't please everyone".
There is an expectation for many live events to be at an SPL that would be considered 'loud'.
Audio engineers indicate the expectation that an event is 'loud' is due:
• to traditional expectations of a high SPL 'standard',
• to the 'Loudness War',
• large venues requiring a high SPL at the stage, to reach people listening further away,
• to lifting SPL over the stage noise,
• to lifting SPL over the crowd noise,
• to people being desensitised to high SPL,
• ignorance of the effects,
• to demands by performers, manager or director,
• to an artist's or engineer's ego or insecurity,
• to peer pressure from other audio engineers,
• to maintaining SPL continuity throughout the duration of an event or festival,
• to an engineer's desire to use the power available and to push the limits,
• to the perception that engineers that can handle louder audio power are seen as more skilled, 44
• to the final act being the loudest act, and
• to hearing impairment that may cause a desire for a louder sound to produce the desired neural
stimulation.
Live Audio Handbook | Page 27Attendees may experience 'ringing in the ears' Monitoring:
after an event. Of the audio engineers surveyed:
46% of audio engineers use a meter to measure SPL
• 79% say attendees believe the effects are at events. Of those:
temporary, • 44% use the correct monitoring scale to monitor
• 53% say attendees believe the 'ringing' is normal average levels that relate to WHO and most
when attending live events, health and safety recommendations.
• 17% say attendees believe that public events are • 20% say their monitoring affects subsequent SPL.
safe, and
• 18% believe attendees are ignorant about safety,
don't care about potential damage, have a HEARING MANAGEMENT IN LIVE-SOUND
sense of invincibility, believe that high SPL is
cool or can be bragged about. As protective measures at high SPL events to
manage participant hearing, of the audio engineers
surveyed:
Responsibility: • 74% believe there should be warnings on tickets,
• 39% believe there should be SPL Indicators,
Who do audio engineers believe is responsible for • 84% believe events should provide hearing
managing safe noise exposure at live events: protection (earplugs),
• 40% personal responsibility, • 74% believe there should be quieter zones,
• 88% the audio engineer, where 86% believe it is feasible to provide a
• 44% the Director or Music Director, consistency of tone throughout a venue with
• 75% the event organiser, areas at a lower SPL that still retain good visibility
• 34% the local City Council, • 80% believe there should be streaming available
• 13% the Government, and to portable devices
• 13% Other - artists, venue owner, crew,
consultant.
Audio engineer's 'mix' decisions are influenced by:
• personal hearing ability, • source material, • peer pressure,
• training, • venue acoustic, • expectation,
• skill, • stage 'volume', • conditioning,
• experience, • mix position, • public response,
• musicality, • preparation time, employer's directive,
• focus, • fixes while mixing, • musician's requests,
• rest, • target audience, • personal responsibility, and
• equipment, • tradition, • legislative restrictions.
34
Page 28 | Live Audio Handbook35
AUDIO ENGINEERS
ON AUDIO ENGINEERS
Few people understand what audio engineers do
and what is involved in producing a high-quality sound.
36
Audio engineering with skilful musicians and high-quality equipment
in a venue with an appropriate acoustic makes the audio engineer's
role easier but is not a guarantee of good sound. The audio engineer is
the final link in the audio chain. They mix the audio sources musically,
adjusting dynamic, tone, and space while balancing participants'
expectations. Their skills, character, preparation, personal hearing
ability, musicality and more affect the final audio product. Amidst a
seamless well-balanced mix, the audio engineer may go completely
unnoticed.
There are factors beyond the engineer's control that affect the
resultant sound. Often preparation time is limited. Not every sound
source can be 'fixed in the mix'. The audio engineer's 'invisibility'
contrasts with the necessity of engineers to build and maintain trust
with musicians, organisers and the audience. These relationships
keep audio engineers employed and help ease the effect of any
unforeseen technical distractions that may arise in the course of a
live event. Establishing trust with other participants requires evidence
of skill, knowledge, diligence, reliability, punctuality, calmness under
pressure, focus and an ability to deliver what is needed. An audio
engineer benefits from the knowledge gained through personal
research, watching and asking others, trial and error, and practice.
34 35 36
Mix of audio engineer Mixing sound waves Chicago, The Court Theatre,
influences affecting choice Christchurch, NZ 2017-18
(SC Sound Op/ Sound Design)
“
And that fake smile you put on when the artist
starts singing and you realise there’s nothing you
can do to make that sound good.- unknown
Live Audio Handbook | Page 2937
AUDIO ENGINEER'S ON AUDIO ENGINEERS
An Impossible Job Description?
If someone were to prepare a job description listing the traits and skills required to be an effective
audio engineer, the list would look something like the following, which has been compiled from
comments by audio engineers in a 2020 international survey52:
Skills, Training and Preparation • Listen to recorded versions of the performance
songs and associated genre. Attend rehearsals
• Be willing to learn and a curiosity about how to familiarise yourself with the target
things work. Read, watch and learn about audio soundscape and arrangement.
processes, sound operation, techniques and • Bring spare cables, mics, DIs, electrical tape,
equipment. Watch other audio engineers and gaffer tape, a marker pen, headphones and a
ask questions (at appropriate times, not when range of adaptors for any occasion.
they are in the middle of a challenging mix). • Make a patch list so as to know how each piece
• Develop a basic knowledge, understanding and of equipment is connected and soft-patched.
practice of: • Line-test inputs and outputs and signal flow
• gain structure, signal flow and PA systems, before musicians and audience arrive. It is much
acoustics, physics, electronics and IT, easier to problem-solve without the added
• critical listening, pressure of people watching.
• music terminology and theory, so as to • Play high-quality recorded tracks that you know
focus intuitively on the art, and be able to well as reference material to compare how a PA
follow a score, system responds to the track. Our hearing may
• microphones: choice, placement and care, have adapted to an inferior quality of sound
• the specific event tools and equipment (listening to poor quality car speakers on the
and develop an ability to use those tools way to the venue). Before an event, remind our
musically to achieve the goals required for ears how something should sound to refocus
the event, and them to a more appropriate target.
• people skills, and maybe even pyscology.
• Practice the art of mixing to develop and Hearing and listening:
improve skills. Some times you and your critical
listening only get better after doing the job • Manage and protect personal hearing as the
many times. primary audio engineer tool that affects critical
• Be prepared, punctual and organised for an listening, ability to 'mix', employment options,
event, with a familiarity of the program material general health, social interactions and finances.
and a run sheet to aim for seamless transitions, • Critically listen to a wide range of music.
while still expecting changes on the day. • Allow rest times away from noise.
Page 30 | Live Audio Handbook“
37
NZSSSO, Christchurch NZ, 2018,
(SC Video/Audio Recording and Post-Production) “I think I’ve done close to 3,000 shows with
the guy (Rod Stewart), so we’re hoping we’re
going to get it right sooner rather than later.”
- Lars Brogaard, FOH
Character: • Develop and demonstrate:
• a desire to get the
• Be calm (or at least appear calm), to keep a best possible outcome,
situation calm and to create a relaxed and • a desire to help others,
positive environment, • a desire to learn,
• Be able to listen to advice from others, to take • a good work ethic,
criticism, be thick-skinned and able to forgive, • a positive attitude,
• Be able to make decisions in stressful situations, • a sense of humour,
• Be able to put aside arrogance and pride, • attention to detail,
• Be efficient in time management, especially in • endurance and stamina,
setting up and packing down, • humility,
• Being a little bit crazy may help, • initiative,
• Be tenacious to keep problem-solving and • leadership,
working towards the best possible outcome, • musical sensitivity, and
• Develop a logical mind that can develop • organisation skills.
repeatable habits/steps to success,
• Have a good work ethic,
• Also, be: Communication
• adaptable,
• a multi-tasker • Be approachable, personable, and a team
• assertive, player,
• committed, • Be able to deal with a wide range of people,
• creative, understanding interpersonal relationships,
• eager, • Be kind and respectful to 'the voices' even when
• enthusiastic, those 'voices' contain critics,
• flexible, • Be willing to ask questions,
• hardworking, • Demonstrate diplomacy and tact,
• kind, • Develop respect and trust so as to be received
• not afraid to try well when suggesting changes to performer
something new, volume and tone,
• open-minded, • Foster good communication with the
• passionate about performers, to pick up their expressions and
the work, subtle cues in order to make adjustments when
• patient, necessary,
• proactive, • Resolve conflicts that may arise, and
• reliable, • Show empathy
• self-confident,
• sensible, and
• willing to learn.
38 38
Shovel Guitar - 'making something musical out of
something that may not obviously be'. (SC made).
Has an 'earthy' sound. Does it need a 'pick'?
Live Audio Handbook | Page 31Technical: • Develop the ability to keep alert, attentive and
focused throughout.
• Through experience and study, have enough • Develop an ability to pay attention to detail
technical understanding and intuition to while maintaining a view of the 'bigger picture'
problem-solve efficiently. to avoid being buried in a technical issue that
• Develop analytic and logical thinking. is insignificant in comparison to what's going
• Visualize signal flow. on with the bigger picture of the show or
• Learn to multitask. Have an "always scanning" performance, potentially missing significant
mind that can be 'one with the music' but at the cues from the artists to the detriment of the
same time, able to notice when there is an audio event.
issue and then fix as seamlessly as possible. • Develop an awareness of surroundings and
• Monitor SPL and sound exposure and respond participants. Respond to the impact of the
accordingly. sound on listeners and balance the audio in
such a way as to maximise engagement.
In the Mix • Aim for seamless transitions to maintain the
illusion of invisible reinforcement.
• Determine that, in the 'mix' the most important • Obtaining the best sound may be 90%
‘thing’ is the most important ‘thing’, whether it be psychology and 10% mic placement.
the artist, a lyric, or a message. All other sound
elements should support the main ‘thing’. Musicality
• Actively become conscious of every audio
element as if heard for the first time. • Have a 'good ear' for the performance to be
• Be aware of every sound source's location, how mixed and the instruments involved. Know how
each sound blends with another, and how each each instrument should sound in relation to
sound source's natural frequencies compete other sound sources within a given song for the
with others. genre, knowing where the melody is.
• Note and respond to each sound's dynamic • Appreciate many musical styles, even if they're
range, giving each their own space, aware not your personal preference.
that music moves and not everything has to • Play an instrument.
be locked down and compressed to the same • Understand the various musical connections
volume. Be sensitive to the changing dynamics that make up the final sound.
to 'ride' the emotion and musical focus to help • Understand musical concepts like melody,
convey the 'feeling' for the 'story' being told. harmony and dynamics.
• Just because a 'mix' has a history of being
constructed in a particular way, does not mean After an Event:
that those ways cannot be improved.
• When dialogue is too loud, the listener can feel • Be pleased that you have stepped up and
'shouted at' and pushed back in their seats. performed a difficult task. Be thankful for being
Quieter dialogue can encourage the listener to part of a fascinating creative industry.
'lean in' and focus more on what is said. There • Coil cables correctly and store equipment safely.
may be times when an authoritative-sounding • Review and learn something from every event,
higher volume may be appropriate. separating what was in your control and what
was not.
39
Page 32 | Live Audio Handbook40
39
“
Yamaha CL5 - Monitors
40
"If you think it’s expensive hiring a good sound engineer,
Outdoor Concert
try hiring a cheap one."
- unknown 41
SC designed fully adjustable system
to hang and steer microphone/s.
'Finding solutions where current
options are limited'
Extra Bits 41
• Good equipment is not a guarantee of a good
sound. In the hands of a good audio engineer,
good equipment helps them get a great sound
easier.
• When evaluating the quality of one piece of
audio equipment like a microphone or speaker,
make direct comparisons between that item
and another that you know well. It is difficult
to appropriately determine an audio element's
different characteristics without something else
to compare it with directly.
• Many digital consoles and processors have
useful options for the experienced engineer but
can confuse the novice. Sometimes a simple
analogue set up is a better option for the
beginner.
QUESTIONS TO PONDER
• How do we, as audio engineers, develop our skills and craft? Are we consciously looking to improve the
live-sound experience?
• Do we act responsibly for the safety of individuals affected by our choices, or do we rely on personal
freedoms, that our patrons are informed and capable of being prepared and making wise choices?
• To what degree is musicality affected in our audio engineering choices of volume, compression, tone,
space and movement? Is compression/limiting overused?
• When amplifying dialogue, do we consider that some cultures may have different preferences: a lower
conversational approach, or a higher, more authoritative-sounding level?
• Could event SPL be lowered by 3 dB (1 dB per year), effectively doubling the allowable exposure time, and
still maintain the concert experience?
• Could a lower SPL and an understanding of safe exposure levels provide the listener with greater freedom
to enjoy a louder event, as is the case with sunscreen and the freedom sunscreen provides on a sunny day?
Live Audio Handbook | Page 33You can also read
