27 51 20 (16822) - Centralized Sound Masking System
Section Cover Page | |
| Section 27 51 20 |
|2010-11-15 Centralized Sound Masking System |
Use this Section to specify a centralized electronic sound masking system generating masking sound from speaker assemblies strategically located above conventional suspended acoustic tile ceilings. Each speaker assembly generates a diffuse and unobtrusive sound with a spectrum shape designed to mask speech and unwanted noise.
This Master Specification Section contains:
.1 This Cover Sheet
.2 Data Sheet – Reference Documents
.3 Specification Section Text:
1. General
1.1 Related SectionRequirements
1.2 Detail Drawings
1.3 Reference Documents
1.4 Description of the Centralized System
1.5 Performance Requirements
1.6 Submittals for Review
1.7 Quality Assurance
1.8 Coordination
1.9 Warranty
10. Performance Verification by Minister
2. Products
2.1 Acceptable Manufacturers
2.2 Noise Generator(s)
2.3 DSP Sound Masking Audio Processor
2.4 Power Amplifiers
2.5 Sound Masking Speaker Assembly
2.6 Equipment Cabinet
7. Accessories
3. Execution
3.1 Delivery, Storage and Protection
3.2 Installation of Equipment and Speaker Assemblies
3.3 Installation of Wiring
3.4 Identification
5. Cleaning
6. Testing, Adjusting and Balancing
7. Demonstration and Training
8. Schedule
3. Detail Drawings:
27 51 20.01 Centralized Sound Masking Spectrum and Tolerances
27 51 20.02 Schematic Diagram
1. General
1.1 RELATED Requirements
.1 WASTE MANAGEMENT AND DISPOSAL: SECTION 01 74 19
.2 Basic Electrical Requirements: Section 26 00 05
.3 Electrical Starting and Testing - General Requirements: Section 26 08 10
1.2 DETAIL DRAWINGS
.1 THE FOLLOWING DETAIL DRAWINGS ARE APPENDED AND FORM PART OF THIS SECTION.
Number Title
27 51 20.01 Centralized Sound Masking Spectrum and Tolerances
27 51 20.02 Schematic Diagram
1.3 reference Documents
.1 AMERICAN NATIONAL STANDARDS INSTITUTE (ANSI):
|.1 |ANSI S1.4-1983(R2006) |Sound Level Meters |
|.2 |ANSI S1.11-1-2004(R2009) |Octave-Band and Fractional Octave-Band Analog and Digital Filters |
.2 American Standards for Testing and Materials (ASTM):
|.1 |ASTM E1374-06 |Standard Guide for Open Office Acoustics and Applicable ASTM Standards |
|.2 |ASTM E1573-09 |ASTM E 1573-02 – Standard Test Method of Evaluating Masking Sound in Open Office |
| | |Using A-Weighted and One-Third Octave Band Pressure Levels |
1.4 description of the centralized system
.1 A DSP-BASED, DISTRIBUTED SOUND SYSTEM TO INCLUDE THE FOLLOWING:
.1 Strategically located speaker assemblies above the suspended ceiling system in areas indicated.
.2 Speaker assemblies generating unique, diffuse and unobtrusive sound with spatial and temporal uniformity, and having a spectrum shape designed to mask speech and low level, unwanted noise.
.3 Minimum system components: speaker assemblies complete with 70.7 Volt audio transformers; power amplifiers; DSP-based, dual channel audio processor with either built-in or separate pink noise generators; equipment cabinet; related wiring and accessories including any required conduit.
.4 All areas to be masked using two (2) independent audio channels feeding alternate speaker placements. Signal input to each channel to be random pink noise.
1.5 PERFORMANCE REQUIREMENTS
.1 PROVIDE SOUND MASKING IN ACCORDANCE WITH THE SYSTEM DESCRIPTION TO ALL AREAS INDICATED ON DRAWINGS AND/OR SCHEDULE. SOUND LEVEL PERFORMANCE SHALL COMPLY WITH THE FOLLOWING ONE-THIRD OCTAVE SOUND PRESSURE LEVELS AND TOLERANCES:
| | | |
|1/3 Octave ISO |1/3 Octave Band | |
|Centre Frequency |Sound Pressure Levels |Tolerances |
|(Hz) |(dB) |(± dB) |
| | | |
|125 |44 |± 3 |
|160 |43 |± 3 |
|200 |42 |+2-3 |
|250 |41 |+1-2 |
|315 |40 |± 1 |
|400 |39 |± 1 |
|500 |37.5 |± 1 |
|630 |36 |± 1 |
|800 |34.5 |± 1 |
|1,000 |33 |± 1 |
|1,250 |31.5 |± 1 |
|1,600 |30 |± 1 |
|2,000 |28 |± 1 |
|2,500 |26 |± 1 |
|3,150 |24 |± 1 |
|4,000 |22 |± 1 |
|5,000 |20 |± 1 |
|6,300 |17 |+1-2 |
|8,000 |14 |+1-2 |
Note: The above values are graphically illustrated on detail drawing 27 51 20.01.
.2 Spatial Average Overall Sound Pressure Levels: Minimum 43 decibels and maximum 45 decibels, A-weighted (dBA).
1.6 submitals for review
.1 REFER TO SECTION 01 33 00: SUBMITTAL PROCEDURES.
.2 Product Data: Manufacturer’s information sheets with specification and warranty information for all specified products.
.3 Schematic Design and Loudspeaker Layout: Schematics of the equipment components and their interconnection and including loudspeaker quantity and location on project plan drawings.
1.7 quality assurance
.1 THE SOUND CONTRACTOR MUST BE AN AUTHORIZED OUTLET OF THE EQUIPMENT THEY ARE BIDDING AND FULLY EMPOWERED TO SUPPORT THEIR WARRANTY.
.2 All system components shall be installed by a qualified sound system installer with a minimum five (5) years experience installing centralized sound systems.
.3 Sound level adjustments shall be done by an approved manufacturer representative, acoustical consultant or trained contractor with measurement equipment having the minimum standards outlined in Section 3.6.8.
1.8 coordination
.1 REFER TO SECTION 01 31 13: PROJECT COORDINATION.
.2 Coordinate the work with ceiling installation and mechanical duct routing.
1.9 warranty
.1 PROVIDE A WRITTEN WARRANTY THAT ALL PRODUCTS INSTALLED SHALL BE FREE FROM DEFECTS IN PARTS OR ASSEMBLY FOR A MINIMUM 2 YEAR PERIOD FROM DATE OF ACCEPTANCE.
1.10 PERFORMANCE VERIFICATION BY MINISTER
.1 MINISTER WILL APPOINT AND PAY FOR SERVICES OF TESTING AGENCY OR UTILIZE HIS OWN FORCES TO TAKE MEASUREMENTS TO VERIFY THAT THE INSTALLED SOUND MASKING SYSTEM MEETS SPECIFIED ACOUSTICAL PERFORMANCE REQUIREMENTS.
.2 Performance verification will be performed after Interim Acceptance of the Work,
.3 Verification by Minister will be performed with mechanical systems shut down in area being tested.
2. Products
2.1 Acceptable manufacturers
.1 ACCEPTABLE COMPONENT MANUFACTURERS INCLUDE, BUT ARE NOT LIMITED TO THE FOLLOWING: DYNASOUND, DBX, CROWN, PEAVEY, TOA, QUAM, ATLAS SOUND.
2.2 noise generator(s)
.1 RANDOM NOISE GENERATION WITH CONSTANT ENERGY PER OCTAVE BANDWIDTH (PINK NOISE) AND SPECIFICALLY DESIGNED AS A NOISE SOURCE FOR ENGINEERED SOUND MASKING APPLICATIONS.
.2 Minimum Spectral Purity: +/- 0.1 dB from 20 Hz to 20 kHz.
.3 Noise Repeat Time: no less than 200 minutes.
.4 Noise generator(s) can either be independent components with CSA approved power supply or internally built within the sound masking audio processor.
3. DSP SOUND MASKING audio PROCESSOR
.1 TWO CHANNEL DPS-BASED AUDIO PROCESSOR, WITH OR WITHOUT BUILT-IN PINK NOISE GENERATOR. SIGNAL PROCESSING CAPABILITIES SHALL INCLUDE BAND-PASS FILTERS, PARAMETRIC EQUALIZERS, ONE-THIRD OCTAVE EQUALIZERS AND INDEPENDENT MATRIX FOR CHANNEL-TO-CHANNEL MIXING.
.2 Nominal line level output of +4 dBu.
.3 High-Pass and Low-Pass filters with variable frequency and slope per channel.
.4 One-Third Octave Band Filters: per channel and to ISO standard centre frequencies from 20 Hz to 20 kHz.
.5 Parametric Filters: per channel with selectable Q and level. Parametric filters shall work in combination with the one-third octave filters.
.6 Frequency Response @ + 4 dBu: +/- 0.5 dB from 20 Hz to 20 kHz, minimum.
4. POWER AMPLIFIERS
.1 MULTIPLE SIGNAL, DUAL OR FOUR CHANNEL, SOLID STATE, EIA RATED,
.2 Minimum Power Output: one (1) Watt per speaker on each channel load,
.3 Bandwidth: minimum 20 Hz to 20,000 Hz +/- 1 dB.
.4 Total Harmonic Distortion: less than 0.1% at full rated power.
.5 Constant Voltage Output: 70.7 Volts; transformer to be internal.
.6 Gain: manually adjustable and incremental to at least 1 dB.
.7 Power Supply: self-contained and CSA approved.
.8 Mounting: standard EIA, 480 mm rack.
5. SOUND MASKING SPEAKER ASSEMBLY
.1 COMPLETE SPEAKER ASSEMBLY WITH CONICAL LOUDSPEAKER, 70.7 VOLT AUDIO TRANSFORMER, PERFORATED STEEL BAFFLE AND STEEL BACK BOX WITH ACOUSTIC DAMPING MATERIAL.
.2 Conical Speaker Size: minimum 100 mm; maximum 200 mm.
.3 Speaker Sensitivity; minimum 90 dB @ 1 Watt/1 Metre
.4 Power Handling; minimum 8 Watts RMS
.5 Speaker Dispersion: minimum 100 Degrees at -6 dB Points
.6 Audio Transformer: 70.7 Volt, mounted to speaker frame with primary power taps at 0.25, 0.5, 1, 2, 4 Watts.
.7 Enclosure: 0.6 mm minimum thickness sheet steel with perforated baffle and sound damping material.
.8 Mounting: three or four point chain suspension.
6. EQUIPMENT CABINET
.1 EIA COMPLIANT 280 MM WALL-MOUNTED RACK OF 1.6 MM STEEL CONSTRUCTION
.2 Hinged back for component cabling access and hinged front security door,
.3 Height and depth to provide fixed mounting for all equipment plus adequate ventilation space to maintain a constant maximum operating temperature below 29 degrees Celsius for all equipment.
2.7 ACCESSORIES
.1 SPEAKER WIRE; COPPER, TWISTED PAIR, INSULATED JACKET, AWG SIZE TO PROVIDE NO MORE THAN 1 DB LINE LOSS PER CHANNEL RUN.
.2 Speaker Mounting Chain: light steel chain capable of supporting at least three times the speaker assembly weight.
3. Execution
3.1 delivery storage and protection
.1 PROTECT ALL EQUIPMENT FROM MOISTURE DURING SHIPPING, STORAGE AND HANDLING.
.2 Deliver in manufacturer’s original unopened and undamaged packages with manufacturer’s labels legible and intact.
.3 Protect any pre-finished exposed surfaces with impact-resistant wrapping.
3.2 INSTALLATION OF equipment and speaker assemblies
.1 SUSPEND SPEAKER ASSEMBLIES THROUGHOUT THE EXPOSED CEILING AREA IN ACCORDANCE WITH MANUFACTURER’S INSTRUCTIONS AND IN A LAYOUT PATTERN THAT WILL ENSURE THE REQUIRED ACOUSTICAL PERFORMANCE.
.2 Suspend speaker assemblies with mounting chains securely fastened to structure. Ensure that there is no strain on electrical wiring.
.3 Mount speaker enclosure with grille facing up to reflect sound from the exposed ceiling structure. Avoid mounting which could result in generation of vibration noise or distortion.
.4 Install equipment securely inside equipment cabinet. Equipment cabinet location will be determined by Architect in consultation with Sound Masking Contractor.
.5 Provide surge protection for all DSP-based equipment and ground audio system to building power supply ground.
3.3 installation of wiring
.1 AVOID DAMAGE TO CABLES. PROVIDE ADEQUATE CABLE STRAIN RELIEF.
.2 Run speaker cables parallel and perpendicular to building lines. Attach wiring to top of structural elements in a non-obstructive fashion. Secure every 3 meters and at changes in direction.
.3 For multiple speaker wire pairs, connect each speaker wire pair to connectors on terminal blocks located behind centralized cabinet equipment.
3.4 identification
.1 LABEL ALL OPERATOR CONTROLS, SWITCHES, AND PANELS WITH P-TOUCH LABEL MAKER USING EXTRA STRENGTH ADHESIVE TAPE. MARK FINAL SETTINGS ON OPERATOR CONTROLS.
3.5 cleaning
.1 ENSURE THAT EMPTY PACKAGING IS REMOVED.
.2 Ensure that any material waste is removed.
.3 Ensure the product is clean and presentable where required.
3.6 TESTING, ADJUSTING AND BALANCING
.1 SCHEDULE TESTING, ADJUSTING AND BALANCING WORK TO BE DONE AFTER ABOVE CEILING MECHANICAL AND ELECTRICAL WORK AND SUSPENDED ACOUSTIC CEILING SYSTEM ARE COMPLETE .
.2 Calibrate measuring microphone and related test equipment prior to testing.
.3 Test, adjust, and balance system with mechanical system and other noise generating equipment shut down in areas receiving sound masking.
.4 Test, adjust, and balance system until sound spectrum and sound levels meet specified performance requirements. Adjust settings of, relocate, or add additional system components, if and as required.
.5 Upon completion of tests, perform walk-through verification of areas to be covered by sound masking. Adjust and re-test areas having abnormal characteristics or levels.
.6 Tests and Test Methods:
.1 Test to determine 1/3 octave band sound pressure levels at minimum of one reading per 350 m2 of floor area to be sound masked.
.2 Test to determine spatial averaged, A-weighted, overall sound levels at minimum of one reading per 100 m2 of floor area to be sound masked.
.3 Position measuring microphone 1.2 meters above floor and minimum 1 meter away from any sound reflecting surface during testing. Position microphone in locations representative of each area to be sound masked.
.7 Measure Sound Pressure Levels using the Equivalent Continuous Sound Level (Leq) mode for a minimum interval of 15 seconds using a manual sweep.
.8 Test Equipment:
.1 Sound Level Meter: to ANSI S1.4, Type 1 or better.
.2 One-Third Octave Band Filter: to ANSI S1.11, Class II or better.
.3 One-Third Octave Band, Real Time Audio Spectrum Analyzer: to ANSI S1.11-2, Class II, Type E or better.
.4 Accuracy of Acoustic Calibrator: within ±0.3 dB at 25°C.
3.7 demonstration and training
.1 DEMONSTRATE OPERATIONAL SYSTEM TO CLIENT BY WALKING THE SPACE.
.2 Demonstrate functionality of the system to the Owner or Owner’s representative.
.3 Train Owner representative to maintain system, as required.
3.8 Schedule
.1 PROVIDE SOUND MASKING COVERAGE IN THE FOLLOWING ROOMS AND AREAS:
.1 [ ]
END OF SECTION
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