live room construction guide

7/31/2019 Live Room Construction Guide

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Live Room Construction Guide

Page 1 of 22Copyright 2011 Glenn Stanton. All Rights Reserved. No duplication without written permission.

Table of Contents

1 Preparation .................................................................................................. 31.1 Existing HVAC ....................................................................................... 31.2 Existing Plumbing .................................................................................. 31.3 Existing Electric ..................................................................................... 31.4 Existing Windows.................................................................................. 41.5 Existing Doors ....................................................................................... 41.6 Existing Walls ........................................................................................ 41.7 Existing Floor ......................................................................................... 51.8 General .................................................................................................. 5

2 Layout ......................................................................................................... 52.1 HVAC ..................................................................................................... 52.2 Live Room ............................................................................................. 6

3 Overhead Insulation .................................................................................... 64 New HVAC System ..................................................................................... 65 Overhead HVAC Duct.................................................................................. 66 Wall Framing ............................................................................................... 7

6.1 Live Room ............................................................................................. 97 Electric ........................................................................................................ 9

7.1 Live Room ........................................................................................... 108 Other Wiring .............................................................................................. 11

8.1 Live Room ........................................................................................... 119 Wall Insulation ........................................................................................... 1110 Ceiling Framing ....................................................................................... 1211 HVAC Silencers ...................................................................................... 12

11.1 Live Room ........................................................................................ 1212 Insulation ................................................................................................ 1213 Drywall ................................................................................................... 1314 Doors & Windows .................................................................................. 13

14.1 Live Room ........................................................................................ 1415 Acoustic Treatments .............................................................................. 14

15.1 Live Room ........................................................................................ 1616 Wiring Termination ................................................................................. 1717 Paint & Stain ........................................................................................... 1818 Flooring ................................................................................................... 1819 Trim ........................................................................................................ 1820 Equipment .............................................................................................. 19


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21 Acoustic Measurements ........................................................................ 1922 THEORY ................................................................................................. 2023 Calculations ............................................................................................ 22


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Get plenty of non-hardening silicone caulk.

1 PreparationThe preparation steps ensure the proposed space has been correctly

configured to ensure that maintenance or emergency access to infrastructure

components is retained, potential impact or infrasonic noise, and vibration

sources are reduced, and potential isolation reduction points are treated.

Additional steps include clean up and finishes that would be difficult or messy

to perform later.

IMPORTANT: All work should be done in accordance with building codes,

community by-laws, and common sense. When in doubt, have a licensed

expert review and/or assist in the alterations and construction. Ensure all work

is done under building permits as necessary to avoid fines and potential

insurance coverage loss.

1.1 Existing HVACMechanical equipment (such as HVAC blowers, laundry machines, pumps,

dehumidifiers, etc) should have isolation mounts installed to decouple them

from the existing floor, walls, or framing. Silencer techniques such as damping

or filtering should be used to reduced encasement noises or noise generatedby air movement (such as an HVAC room air supply through a wall or door), if

the noises are potentially intrusive in the studio space.

Existing duct work should have proper isolation mounts and decoupling

segments added to reduce noise transfer. Duct board or liner should be used to

shield ducts which could pick up or transfer sound between the studio and

other spaces.

1.2 Existing PlumbingExisting plumbing that may require access to valves, meters, building

penetration, clean outs, etc should be re-routed where possible to ensure thatnew construction does not impede maintenance or emergency access. Pipes

should be properly suspended on isolating hangers to reduce structure borne

noise and vibration. Plumbing without air absorbers should be corrected to

avoid banging in the supply pipes. Drain pipes should have damping material

wrapped on them to reduce ringing or general noise levels.

1.3 Existing ElectricExisting electrical boxes, access panels, lighting, outlets, and safety devices

should be re-routed or removed in preparation for the new construction. In the


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wall outlet boxes which will be retained should be covered with putty pads

(inside the wall) to seal them air tight. Conduits which cross room boundaries

should be split and re-connected with a soft decoupling connector. Lighting

boxes should be sealed where air leakage represents a path where isolation

would be reduced. Ensure wiring is in good and operating condition and is

wired to code. Ensure the wiring will not vibrate by adding additional wire

fasteners as needed.

1.4 Existing WindowsRemove live room windows and resize openings to fit new glass blockwindows. Ensure the windows seal correctly. Ensure any egress windows are

fully functional. Seal any gaps around the windows to ensure they are air tight.

1.5 Existing DoorsRemove live room doors and resize openings to accommodate new doors.

Close off existing block wall door between live room and office. Ensure the

remaining doors seal correctly. Ensure the doors are fully functional. Seal any

gaps around the doors to ensure they are air tight. If replacing the doors,

ensure the framing for the new doors is in good shape. If enhancing the doors,

add additional wall studs on each side to ensure good structure support for the

added weight.

1.6 Existing WallsExisting walls should have any interior GWB (if framed) removed to avoid a

third leaf condition or in preparation for enhancement. Block and concrete walls

should be inspected to ensure structural soundness, sealed, and prepared as

needed to support the new construction.

For block walls, ensure they are sealed and in good shape. Ensure any framing

is properly attached and does not vibrate or shake. Seal (with caulk) any

attached framed walls to ensure they are air tight.

Identify locations for the isolation mounts (angle brackets attached to the

existing walls) to ensure they are structurally sound enough to stabilize the new

walls.

Seal any and all air gaps between rooms and floors. Ensure any fire stops or

other safety assemblies are restored or installed as required by building codes.


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1.7 Existing FloorIf you are planning on using acid wash, stains, and sealant to finish a concrete

floor, then ensure the floor is reasonable level and smooth, cracks are filled and

sealed, old paint and glue are removed and the floor is clean. For this type of

treatment, it can get messy so doing the staining is best done before other

work.http://www.concretenetwork.com/staining-concrete/has a decent set of

articles on staining concrete floors.

Remember its concrete it will take a lot of abuse so just protect it from

scratching during construction and youll be fine.

Moisture control is important so ensure the floor actually stays dry by laying a

plastic sheet on it overnight to see if any moisture collects. If it does collect

moisture you will need to fix that before proceeding.

1.8 GeneralIn general, the goal of the preparation phase is to move items out of the way in

order to preserve maintenance access, isolate and seal the surrounding walls,

ceiling, and floor, and correct noise sources from mechanical equipment.

If you can see light, or air can get through it, then its not sealed.

2 LayoutSo now youre ready to begin. The first step is to take painters tape and layout

the floor plan of the new live room, paying attention to spaces between walls,

door and window openings, and treatment placement. The goal is to ensure the

design drawings are mainly correct and that the layout actually works for you.

This is very inexpensive to do (although it does take a few hours) and can

eliminate a lot of rework later (when it is expensive) by getting a feel for the

new space and how it will work for you.

You want to use a wide tape (2) for the walls and treatment frames. Use thin

tape (1/2) (preferable another color also) to layout overhead objects such as

vents, treatments, lights, and other divisions.

2.1 HVACRun thin tape to layout the approximate location of the new duct soffit in the

room. Layout HVAC to all rooms to ensure proper duct bends are incorporated.
http://www.concretenetwork.com/staining-concrete/http://www.concretenetwork.com/staining-concrete/http://www.concretenetwork.com/staining-concrete/http://www.concretenetwork.com/staining-concrete/


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2.2 Live RoomThe live room has a new entry door which replaces the existing door. Ensure

the location where the new walls will change height is correct in relation to the

overhead ducting. This room has a number of broadband composite absorbers

spaced around the room. Mark the location of the overhead vents, treatments

(absorbers), and lights using the thinner tape. Run a thin tape line to mark out

the path for the audio and network wire conduit.

3 Overhead InsulationOnce the layout is complete, we ready to add insulation into the overhead roof

space. Ensure the overhead trusses / joists have minimally R30 insulation in

available spaces between trusses. Do not pack the insulation tightly. It is more

effective to have the air space than to cram the space full of insulation.

4 New HVAC SystemNOTE: Installation of the new HVAC system should be in accordance with

professional advice from a licensed HVAC engineer, the manufacturers

recommendations, and all applicable building and safety codes.

The new HVAC system should be isolated from the roof through the use of

isolation chassis, Kinetics (or equiv) pads, or other commonly used isolation

mounts to decouple the new unit from the floor, walls, and other structures.

Pipes, ducts, wiring, exhaust vents, etc should all be decoupled as necessary to

prevent conduction of vibration to the building structure or the duct system.

The HVAC unit and ducting should be configured for the lowest possible air

velocity (preferably 200FPM, but up to 350FPM is acceptable) for approximately

800-1000CFM air flow.

The new HVAC unit should have cooling, fresh air exchange, pressure relief,

etc in accordance with the latent and live loads for the locale, as well as provide

correct system pressure, velocity, and dehumidification.

5 Overhead HVAC DuctInstall the main HVAC ductwork. The ducts are quite large and would be

difficult to install after the ceiling is put in place, and to ensure the trusses/joists

clear the new duct work, installing it first enables adjustments to be made to

the inner wall and ceiling assemblies.

The duct should be superduct (duct board or lined duct, or equiv.) to ensure

that sound transfer within the duct is minimal.


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Ducting should be mounted from the overhead floor joists using isolation

mounts to ensure the duct does not contribute to structure borne noise

transfer. NOTE: this assumes the structure is capable of support the duct.

Openings in the duct can be cut after the inner ceiling joists are in place to

ensure proper placement of openings and silencers.

Corners in the duct should use turning vanes to ensure smooth air flow.

Pressure relief, dampers, and other duct equipment should be installed at this

time. Devices requiring maintenance or replacement should be installed in the

HVAC closet of at the opening points as the studio construction will not permit

future access.

The return duct will terminate into the living space outside the studio in order to

facilitate return for the rest of the basement. This return is approximately over

the existing wall door.

6 Wall FramingWall framing is all 2x6 (or better) construction with studs 24 o.c. and a single

bottom plate, and two top plates. Blocking is used between studs to ensure

rigidity as the walls are load bearing (supporting the 3 new drywall layers as

well as acoustic treatments, etc).

Example of inner ceiling supported on truss framing.


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All trusses/joists will have 1/8 felt tape on their face to help decouple drywall

from the framing. Felt tape is adhesive or stapled 24 o.c.

Example of inner wall on floor and floating floor.

All walls rest on 1/4-3/8 Neoprene rubber (or Sorbethane, Sylomer, or equiv)

to decouple the walls from the floor. The top plates of the walls have a layer of

rubber as well to decouple the ceiling joists from the wall.

All inner walls are stabilized with isolation clips (such as Mason Industries WIC

or Pac-International isolation mounts). There should be a clip used every 8, or

minimally 2 per wall. Check with the manufacturer instructions. This includes

the wall-to-wall mounting between the live and control rooms. Mounting can be

stud-to-stud, or in the case of block wall, use an L angle bracket attached to

the block or concrete wall to provide attachment for clip.


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Example of Mason Industries isolation mount WIC installed between existing

block walls and new stud walls.

Doors and windows use 2x10 headers. Doors have 3 studs on each side to

ensure support for extra heavy doors.

Effectively all wall framing is standard construction except that the door and

window framing is stronger than typical. All stud wall assemblies are designed

to be isolation walls and will support multiple layers of drywall, insulation, and

be sealed airtight.

6.1 Live RoomThe live room wall framing has two (2) different levels one level for the HVAC

soffit enclosure to block the sound transfer to the existing HVAC duct, and a

taller level for the section above the new HVAC ducting.

Example of soffit for HVAC duct

7 ElectricElectrical wiring is important to ensure easy access to power, with clean

grounds and placement conducive to room usage.

A new sub panel should be installed. 50 amp or better such as D-Square.

All wiring will be 3 conductors #12 AWG Romex or BX with an additional

ground wire run for star grounding at the sub panel and new ground stake.


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Star ground should terminate in a separate (small) panel to ensure single

ground point before being attached to main panel and earth ground (not

technical ground).

Outlets and wall penetrations should be staggered to avoid direct paths

between openings. All penetrations (outlet, switch, and other boxes) should be

encased with putty pads to ensure airtight seal.

Example of star ground arrangement.

7.1 Live RoomThe live room as 3 wall switches placed just inside each entry door. Eachswitch controls a set of track lights to enable a change in the lighting level

without using dimmers. On each side of the live room door are quad power

outlets. On the long walls is quad power outlets.

Overhead are track lights to avoid significant penetration in the ceiling drywall.


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8 Other WiringOther wiring includes audio cabling (snakes, discrete cables), coaxial cable

(television and video), network cables (CAT6E), fiber optic cables, USB and

Firewire (IEEE1394), video monitor or keyboard extensions, speaker wires, and

wiring for smoke and CO detectors, safety and monitoring equipment, etc.

Audio cables (snake cables) should be run through conduit if future expansion is

planned. Audio cables must be separated from electrical and other wiring by 2

or more and should not run in parallel (crossing at right-angles is OK). When

running conduit, a cable pull line should be run to ensure new cables can bepulled through. Quality cabling is important for sound quality. Using

Conduit for audio cables should be mounted on the wall and run just below the

soffits to mask it and avoid penetrations.

digital wire

snakes is preferable for audio because of its lower capacitance.

Any penetration of the drywall will need to be sealed thoroughly. Conduit

should have sections which decouple the conduit between rooms to ensure

that noise and vibration is minimized. Conduit above the rooms should be

suspended with isolation mounts.

Speaker wire should be in conduit and fully separate from audio cables.

All audio and other cable terminate to panels in each room. Good quality

termination (XLR, TS, TRS, RJ-45, etc) should be used.

8.1 Live RoomThe live room audio panels should be located in a position convenient to allow

cables to be connected from anywhere in the room while minimizing cables

that lay across the floor.

9 Wall InsulationThe wall insulation can be installed after (or before) the wiring is completed(depending on how the electrician prefers to work) but by installing the

insulation after, the wiring is easier to inspect and clean up (drill scraps etc),

and there will be less disruption to the insulation.

R19 insulation should be used all round. FSK or unfaced insulation batts can be

used. The important point is to ensure the insulation will be in contact with the

drywall layers.


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10 Ceiling FramingThe ceiling framing is based on roof trusses in accordance with building code.

this may be 24 or 48 o.c. and strong enough to support 20lb/ft2 dead weight

5x 5/8 drywall layers plus ceiling treatments etc.

All joists will have 1/8 felt tape on their face to help decouple drywall from the

framing. Felt tape is adhesive or stapled 24 o.c.

11 HVAC SilencersIt is important to the isolation of the space that the HVAC penetration into therooms is indirect to prevent sound transfer, is decoupled, to avoid structure

borne vibration and noise, and preserve most of the duct area to ensure low

velocity air flow.

NOTE: if you cannot achieve complete silence, then opt for balanced HVAC

noise (i.e. a good quality noise rather than inconsistent or rumbling etc noise).

Commercial products are recommended when possible. It is also possible to

build silencers using MDF (for mass), duct liner (for insulation), and building

them to fit in-between the new ceiling joists so they can be properly sealed.

The silencer is attached to the underside of the main ducts, or in the case of

the returns in the live room, in a smaller duct to preserve the flow from the

living space. If using commercial silencer tubes, remember the penetration into

the room must be encased in a mass enclosure to preserve isolation.

All registers should be diffusive and quiet. When choosing between diffusive or

quiet, choose quiet.

11.1 Live RoomThe live room has 6 supply and 6 return vents on each of the respective duct

soffits. The soffits turn 90 degrees toward the middle and then 90 degrees up

to the main ducts overhead. The connection between main ducts and soffit

ducts is flexible duct to avoid structure transfer of sound.

12 InsulationWith the duct, framing, wiring, and silencers in place, its time to put in the

insulation. R30 is used all around for the ceiling. R19 is used in the walls. There

should be air space. Air space is good

Insulation can be FSK or un-faced insulation batts. Insulation should be installed

to ensure it will firmly contact the inner drywall.


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13 DrywallThe drywall is the isolation mass. It is multiple layers of 5/8 drywall. The

trusses support 3 layers and then the isolation clips and hat channel attached to

the trusses through the drywall then support 2x drywall layers. Stagger the

corners of the wall drywall. Leave about 1/4 of space to allow for sealing

components. Add backing rod and caulk to seal between edges. Repeat per

layer. Stagger each layer to ensure seams do not line up. Seal each layer with

spackling mud. Perform finishing steps on last layer only.

It is important to have the layers staggered to ensure the walls and ceilingremain as decoupled as possible while sealing airtight and not leaving gaps

where the mass would be significantly reduce (thus losing isolation value).

The drywall mud can be smoothed by using a damp fine scrubber brush (with a

handle) and a bucket of water. This speeds up smoothing out the mud by

feather and significantly reduces dust.

The entry between the live room and other rooms need to have the gap (which

should have the rigid insulation in place) covered with cloth or jamb extensions.

This traps any insulation particles and keeps the rooms from contacting each

other. The room side of the entry is trimmed with wood as desired.

14 Doors & WindowsDoors and windows are holes in the isolation that has so far been built. To

reduce the impact of doors and windows on the isolation, the doors and

windows must have approximate the same mass as the walls, and be fully

sealed to ensure no air passes through.

All doors will be solid core, or if the door has glass, the glass will be heavy,

double-glazed with a minimum of 1/2 between panes. Doors with glass should

be set back to back with other glass doors to ensure effective isolation. NOTE:

professional grade acoustic isolation doors with windows are available fromcompanies like Overly. The door should have seals which ensure a positive seal

when closed. This can be achieved by layering the seals, using magnetic or

spring loaded seals, and cam hinges to raise and lower the door onto the seals.

Windows should be exterior grade (or acoustic isolation grade even better) and

be doubled-glazed with a minimum of 1/2 between panes.

All glass should be the laminated type.


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Solid core doors (assuming theyre commercial or residential type) should be

enhanced with the addition of lead sheet (if possible) and 3/4-1 MDF to

increase the mass.

Door frames should be sealed tightly to the wall frame to ensure no air can

pass through in the event of gaps in the trim or drywall edges.

14.1 Live RoomThe live room has three doors. The main entry door is a solid core door. The

side entry door into the office room can be a window or solid core door. The

center door (facing the hallway) is a solid core door. These doors should be very

heavy to ensure minimum sound transmission.

15 Acoustic TreatmentsThe acoustic treatments are the second key component in the live room

assembly process. Isolation blocks sound, acoustic treatment controls the

sound to create a balance in the frequency response and to control time

domain related artifacts (reflections, echoes, etc).

The treatments consist of broadband composite absorbers which act upon the

pressure of the sound wave to attenuate a given set of frequencies. Typically,

these absorbers work on 50hz and up, with high frequencies often being

absorbed in excessive of low frequencies (care must be taken to balance the

amount of high frequency absorption in contrast to low frequency absorption).

Example of a broadband composite absorber.


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There are Schroeder diffusers which are based on mathematical principles to

create diffusion through phase attenuation. These devices can be quite

effective and often very cool looking. Quadratic Residue Diffusers (QRD),

Skyline, and other types are available. RPG is an excellent source of these

types of products.

Example of the QRD porous absorber ceiling treatment.

Finally, the room itself has acoustical properties based on its size, dimensional

ratios, materials, etc. By defining a good set of room ratios, building materials,

and construction techniques, its possible to have a decent sounding room

before any additional treatments are added.

NOTE: when constructing acoustic treatments with frames that will be covered

with cloth, its a good idea to paint the frames the same (or close) color as the

cloth to hide the frame as much as possible.

The porous absorbers are constructed of 2x2 frames to enable maximum

exposure of the 4 rigid insulation.

NOTE: all cloth should be flame retardant or treated with flame retardant.

A gobo can be used to provide bass absorption and reduce reflections off the

instruments and provide a bit of isolation.

The gobos are a 2x6 frame with 4 rigid insulation covered with cloth. A top

plate is added and stained to match other wood in the room. The back of the


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gobo has a 3/4-1 MDF panel which acts as a membrane panel for very low

frequencies.

NOTE: a gobo tends to be very heavy. You can use a wide trim plate

underneath, or angled support brackets, to support the gobo.

Using furniture sliders on the bottom of the gobo can make moving it easy

but the bottom of the gobo should have 3/8 Neoprene rubber or carpet pad to

enable it to seal to the floor.

Example of the gobo.

The upper short walls are a deep porous absorber with a layer of heavy rigid

fiberglass and then filled with pink insulation. This will provide significant bassabsorption as well as high frequency absorption.

15.1 Live RoomThe live room primarily uses QRD-porous diffuser/absorbers on the ceiling and

broadband composite absorbers spaced evenly around the room.

The live room has absorption soffits on the top of each short wall. Additional

absorbers can be added if needed to trim the room response.


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Amplifier risers are used to isolate the bass and guitar amps from the floor of

the live room. Gobos can be placed in front of the amps to reduce their volume

in the room and thereby helping to prevent bleeding between micd

instruments.

The drum kit sits on a massive floating floor filled with sand which has

significant damping and which isolates the drum kit from the floor (a significant

reduction in flanking or structure borne sound).

Alternatively, a decoupled drum riser or amplifier riser can be added to further

reduce any transfer.

Example of drum riser.

NOTE: the drum riser shown here is square. It is more likely that a 5x8 or

5x7 drum riser will be adequate and easier to place in the room.

16 Wiring TerminationWith the rooms constructed and the initial treatment completed, its time to put

the wiring termination in place. Power outlets are attached to the wires,

switches are put in, and the non-electric wiring is terminated to the appropriate

panels such as network, telephone, coax, video, fiber optic, USB and Firewire,

as well as the audio cables.

Wire termination often requires the right tools to press fittings on the ends of

cables, soldering, and testing. Testing is important to ensure proper


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performance of the cables as well as ensuring electrical safety. NOTE: If you

dont have experience doing this, then this is one of those items where hiring

someone with all the tools and experience will improve your chances of

successfully having all the wires actually work when you are done.

Audio cables typically will be terminated to a patch panel in each room so that

you have maximum flexibility in organizing the connections to the mix desk as

well as staying organized during a recording session where you might have 20-

30 microphones and audio inputs, as well as capturing MIDI singles or using

ReWire devices between synths and rack equipment or older PCs.

17 Paint & StainPaint the walls and ceilings.

Color is important to the overall feel of the space and can help provide the right

mood as well as improve visibility of television, monitors, and assist with

reducing reflections in windows (dark colors tend to be less intrusive than

bright ones). Also, creating a neutral level can be helpful if using video or photo

editing where non-neutral colors could impact your interpretation of the colors

on the screen.

I prefer good quality paints like Benjamin Moore or Dutch Boy, and stain likeMinwax, but let your experience guide you. Low VOC may also be important

since the rooms are sealed and the vapors will be coming out of the surface for

a while. Use multiple coats to ensure a good finish.

Pre-staining the trim and boards can simplify life as well and then just do touch

up once you put them into place.

18 FlooringWhen installing the flooring, be sure the flooring does not touch the walls.

Leave a gap on the edges and plan to hide it with trim.

Do not use carpeting unless you are trying to create a deader space in one half

of the live room. Best bet is to have some 8x6 or 7x5 carpets you can roll

out/up as needed.

19 TrimThe trim around doors, window, and the floor should be installed to cover gaps,

and in the case of non-coupled assemblies (like the floor and walls, or ceiling

and walls) ensure the trim is attached to only one or the other of the

assemblies and enough to hide gaps.


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20 EquipmentInstall the equipment and furniture. Get the electronics racked, wired, and

connected to the wall panels.. Tables, lamps etc.

21 Acoustic MeasurementsOnce the room is finished, its time to take some acoustic measurements to

determine if there are any remaining adjustments to be made. Your ears can

tell you a lot about the space. Does it sound good? If not, there may be some

frequencies that need to be tweaked. Some may be due to the room

characteristics, some may be due to the equipment needing some EQ, and

some may be due to your ears hearing things differently than before.

If you have enough ear training to recognize the problem frequencies, thats

great! If not, then using a program like Room EQ Wizard can help to determine

what the listener is hearing in terms of frequency, energy, and time.

Once the measurements are made, determine if EQ will help, or if the room

needs further adjustments. If something is dipping or the RT60 is too long

(large bass levels on a certain frequency) then the room is the likely culprit. If

something is peaking then it may be the room, equipment adjustments (stuff

happens), or it may something that can be fixed using a little bit of EQ acrossthe mains (a touch too much 250 Hz for example).

Room problems will need additional treatments depending on the problem.

Broadband problems need broadband treatment, single or small frequency

ranges need point solutions such as a panel trap, a Helmholtz resonator (a tube

type), or alterations in the absorber configuration (which is why we use screws

or hidden fasteners instead of nails to hold the treatments to the walls).


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22 THEORY# Real sound isolation is achieved with massive construction, an airspace and

elimination of any structural connections that may transmit sound.

Unfortunately, it is very difficult to properly isolate sound when building a studio

in an existing residence; mainly because of the common lightweight, wood

frame construction and the presence of windows (it's important to fill windows

with materials comparable to the rest of the wall). For new construction, you

should specify walls with a high STC. An appropriate STC for a home studio

depends on the specific activities taking place within the studio. Most likely, it

would require an STC of 60 or more. Although STC is a good rating for speech

frequency, it does not consider the low frequency sounds.

# Achieving the optimum interior acoustic environment involves protecting the

live room from noise (noise within the space and noise transmitted into the

space) and controlling the reflections within the space.

# Assuming all transmitted noise is controlled, the primary noise concern is

from the HVAC system (heating, ventilation and air-conditioning). All mechanical

equipment must be controlled to a very quiet level (NC 20-25).

# Note: Absorption and diffusion materials only help the interior acoustic

environment and do not help with isolation.

# It is important to examine the ratios of the room's dimensions in addition to

the room's reverberation time and any potential problematic reflection (such as

from concave, reflective surfaces or peaked/domed ceilings). Certain room

dimension ratios are better suited than others for achieving a rich acoustic

environment. The goal is to find ratios that allow even distribution of sound

across the frequency spectrum. When this happens, tones are reinforced

equally and the least amount of "coloration" occurs. Colorations largely

determine the quality of sound in a smaller. These colorations, caused by room

resonances (modes), can degrade the quality of music and speech, creating anunnatural and monotonous emphasis at certain frequencies.

# Assuming any transmitted noise is controlled, the primary noise concern is

from the HVAC system (heating, ventilation, and air-conditioning). All

mechanical equipment should be controlled to about NC 25-35. Excessive

HVAC noise is best addressed in the design phase, as it is difficult to control

after construction. A system upgrade might be the only post-construction

solution.


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# It is not necessary to cover every surface in the studio with a sound

absorbing material. This would create an acoustically "dead" environment with

too much bass sound. To create the optimum acoustic environment, a balance

of absorption and diffusion should be considered. There are several

commercially manufactured products for both absorption and diffusion.


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Page 22 of 22

23 CalculationsThese calculations are the approximate characteristics of the design.

From Measurements

ratio size m sqrt(2) even ok coprime 38% 42% 58% 62% 38% 42% 62%

h 1.00 11.25 3.43 1.23 FALSE TRUE h-w TRUE 4.28 4.73 6.53 6.95 6.15 6.86 10.37 h

w 2.22 25.00 7.62 0.57 FALSE TRUE l-h TRUE 9.50 10.50 14.50 15.45

l 3.16 35.50 10.82 0.00 FALSE TRUE l-w (h) FA LSE 13.49 14.91 20. 59 21.94 9.36 10.45 15. 80 w

bolt ebu iec >5% walker 9. 17 9. 25 9. 49 level

FALSE FA L SE FA L SE TRUE FALSE 2. 13 2. 30 3. 13 delay (ms)

2. 85 2. 93 3. 17 level

15.59 17.15 24.85 delay (ms)

ax 1st ~note ax 2nd ~note ax 3rd ~note ax 4th ~note ax 5th ~note ax 6th ~note

h 50.17 G1 100.34 G2 150.51 D3 200.68 G3 250.85 B3 301.03 D4

w 22.58 F0 45.15 F1 67.73 C2 90.31 F2 112.88 A2 135.46 C3

l 15.90 #N/A 31.80 B0 47.70 F#1/Gb1 63.60 B1 79.50 D#2/Eb2 95.40 F#2/Gb2

vol surf edge area perimeter T(ms) r (ms) Dc mfp Dc(2)

ft 9984 3136 287 888 121 11.28 251.21 15.90 12. 73 4. 99

m 282.73 291.37 87.48 82.45 11.24 23.70

rt60 eyring millington Fc Fs Fc2 davis B fs unsupp dif fract ray

0.79 0.70 0.78 132.97 105. 39 110. 76 301. 03 2. 80 9 9. 75 15 .90 200. 68 399. 02

0.35 ~note ~note ~note ~note 6.22 ~note ~note ~note ~note

C3 G#2/Ab2 A 2 D4 G2 #N/A G3 G4

ratios diatonic phidev modes df lineal phideal phidev2

h-w 2.22 iii 0.43 1494 0.09 71.75 16.94 h 4.02

w-l 1.42 +IV 0.14 27.41 w 1.70

h-l 3.16 III 1.09 44.34 d 6.25

first reflection

live room construction guide

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