section 4 - the acoustic characteristics of space

7/23/2019 Section 4 - The Acoustic Characteristics of Space

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The acoustic characteristics of space

Musical spaces

There are a number of factors that must be considered when building a recording

studio from scratch. Too much absorption in a room can be bad for mixingpurposes, and probably won’t combat the problem of leakage (the escapement

of sound). But rooms that are too lie will make it nearly impossible to create a

credible mix. The !oor of a

studio needs to be !oating on

a multitude of layers,

resulting in the stop of

resonance spreading. "tudios

should also hae at least an

outer wall and inner wall,

with more often than not,

some type of absorption in

between. #ny glass panels

should be doubles, with one

slightly at an angle $ helping

di%use the sound as it traels

through. #dditionally, the

doors in studios should be extra thick, in order to stop sound escaping, resulting

in a cleaner and more accurate mix and master.

The building of a studio is &ust one factor, not to mention the ambience and

re!ectie nature of the room. This is not only important for instruments beingrecorded but also for the mixing stages as well. #ll these rules and ways of

building a studio apply to multiple sound houses, for example, music enues and

the theatre.

#coustic characteristics

'irtually eeryone underestimates the importance of acoustic treatment. eople

usually spend all of their money on high end gear, thinking it’s the higher

priority, then after a month or two of unsuccessful pro&ects, they stumble upon

the real cause of their frustrations $ sound proong and acoustic treatments.

'ery often, musicians will use these two terms interchangeably, mistaking one

for the other, when really each one is completely di%erent. "oundproong is

intended to minimise the leel of sound that passes through the walls by

blocking them with heay dense building material. The benet of this is that you

can record wheneer you wish without worrying about you or your neighbour

disturbing each other whilst in action. #coustic treatment on the other hand,

aims only to control the re!ections within the room to make better sound

recordings. *xamples of acoustic treatments are+ bass traps, acoustic panels and

di%users.

# direct sound is uickly followed by early re!ections and then a gradual decayof reerb. The larger the room the more likely the reerb time will be longer, but



this will also be determined by how re!ectie the surfaces are. #lso, studios tend

to hae a -lie enddead end’ design $ absorptie features by the engineer, but

more ambience for the clients at the rear. Too much lieliness in a studio control

room will not allow you to mix e%ectiely. /pposing parallel walls in studios can

gie rise to a phenomenon called -standing waes’. These occur when sound is

re!ected back along its own path causing phase di%erences to interfere with a

room’s amplitude response. roblems that usually occur with this would be

increasing and decreasing olume leels at arious freuencies. The e%ected

freuencies will be those whose waelength is mathematically related to the

distance between the opposing surfaces (wall to wall, !oor to ceiling, any !at

surface parallel another !at surface).

#coustic treatment

#bsorption coe0cients are numbers between 1 and 2 which indicate how well a

specic type of material can absorb that certain source of sound energy.

3i%erent freuencies hae di%erent absorption coe0cients $ this would be a

factor to take account of when building a studio.

3ue to sound being omnidirectional, when playing music out of

monitorsspeakers, sound will re!ect o% walls. #s sound traels at extreme rates,

this causes for us as hearers to hear the direct sound source, as well as the

re!ections of what &ust happened a millionth of a second later. #s a result, this

could cause the mixing process to be a nag, as when played back o% the

monitors in the studio it sounds radio ready, but when placed in the car stereo

system, it doesn’t. 4urthermore, to sole this problem, acoustics such as+ skyline

di%users can help $ as they use their di%erent heights of wood in order to scatterthe sound re!ections across the acoustic source. 5oweer, a less expensie

approach can also be used, and this is simply by placing your speakers away

from any corner of a wall, and letting them sit on a speaker stand with possibly a

monitor isolation pad, in order to reduce the leel of ibrations. /erall, speaker

placement is ery crucial and can be extremely benecial in the outcome of your

pro&ects $ if placed right.

"pectral analysis is the analysis of a spectrum of freuencies.

6astly, eualisation is a deice circuit or piece of software that lets you control

the relatie amplitude of arious freuencies within the audible bandwidth. #s a

result, this can+ correct specic problems, oercome deciencies in the freuency

response of a microphone, and allow contrasting sounds from seeral

instruments or recorded tracks, and many more. There are two main types of *7+

Bell (or peak) *7 and "heling *7. "heling *7 refers to a rise or drop in a

freuency response. /n the other hand, the Bell *7 is the most common *7 and

is created by a peaking lter and as its name implies a peak8shaped bell cure

can either be boosted or attenuated around a selected centre freuency.

# graphic euali9er is a high8delity audio control that allows the user to see

graphically and control indiidually a number of di%erent freuency bands in astereophonic system. # typical graphic euali9er consists of seeral audio



lterampliers, each centred at a specic freuency in the audio range. Most

graphic euali9ers hae two identical sets of lterampliers, one for each

channel in a stereophonic system.

By #kai. M

section 4 - the acoustic characteristics of space

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