tutorial acoustic enhancement - audio engineering society · aes 59th conference – july 2015...

ACOUSTIC ENHANCEMENTTutorial

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purpose

• adaptation of the acoustic environment tothe requirements of the performance

ØA room suited for this

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purpose

• adaptation of the acoustic environment tothe requirements of the performance

ØSound good for an event like this

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purpose

• adaptation of the acoustic environment tothe requirements of the performance

ØA room that looks like this

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purpose

• adaptation of the acoustic environment tothe requirements of the performance

ØTo sound like a room likethis

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what?

• reverberation• early reflections• direction

(lateral/medial/elevation)

• loudness

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reverberation

natural acoustics:• room volume• absorption• coupled rooms

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reverberation

electronic enhancement:• regeneration• synthetic generation (in-line)§ all pass filtering§ multiple reflections/FIR filtering§ sampled reverb/convolution

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early reflections

natural acoustics:• orientation of reflectors• placement of absorption

electronic enhancement:• electronic delay• redistribution

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direction

natural acoustics• room shape• distribution of absorption/reflection

electronic enhancement• balance of loudspeakers in enhancement

system

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loudness

• passive/natural acoustics§ inverse proportional to volume and absorption

• regeneration§ proportional to RT60

• in-line§ relatively independent of acoustic parameters

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electronic systemsacoustic feedback

ways to control:• microphone configuration• loudspeaker configuration• loudspeaker/microphone relation

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electronic systemsstability improvement

• multiple (independent) channels§ band limited - high gain/channel§ wide band – low gain/channel

• linear EQ

• de-correlation§ time variant§ time invariant

• echo cancelling

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implementations

LARES

Assisted ResonanceRODS

ERESWFS

AFCCarmen

Vivace

Constellation/VRASSIAP

ACSMCR

VAP

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implementationsreverberation generation

rege

nera

tion

allp

ass

FIR

conv

olut

ion

MCR XLARES X

ACS XSIAP X

Carmen X Constellation X ? ?

Vivace XVAP X X

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implementationssignal pick-up

dire

ct

inte

rmed

iate

reve

rb

no.m

icr.

MCR X largeLARES X small

ACS X mediumSIAP X small

Carmen X medium/large Constellation X large

Vivace X smallVAP X medium/large

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implementationsearly reflection control

MCR noLARES limited

ACS yesSIAP yes

Carmen no Constellation yes

Vivace yesVAP no

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implementationsdirection

MCR noLARES yes

ACS yesSIAP yes

Carmen no Constellation ?

Vivace yesVAP limited

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implementationsgain

MCR proportional to RT60LARES largely indep. of RT

ACS largely indep. of RTSIAP largely indep. of RT

Carmen proportional to RT60 Constellation partly proportional to RT60

Vivace largely indep. of RTVAP partly proportional to RT60

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implementationsmicr. - speaker relation

MCR distantLARES distant

ACS distantSIAP distant

Carmen close Constellation distant

Vivace distantVAP close

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implementationsdecorrelation

MCR microphone speaker distanceLARES time variant

ACS time variantSIAP time invariant

Carmen time variant Constellation ?

Vivace time variantVAP time invariant

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summary

• regeneration systemsoffer good reverberation,essentially RT variation only

• in-line systemsearly reflection manipulation,RT quality dependent on the reverberator

• microphone configurationhas significant influence on enhancementcapabilities

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Remember

• there is more to acoustics than justRT60

• acoustics should not be noticed

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worth reading

Design Criteria for Acoustic EnhancementSystems

Ben Kok, Wim Prinssen6th ICSV, Copenhagen, July 1999

Variable Acoustics means Variation ofReverberation Time – does it?

Ben KokNAG-DAGA, Rotterdam, March 2009

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THANK YOU

ben@benkok.comwww. benkok.com

www.linkedin.com/in/benkok