Sound is usually measured with microphones responding proportionally to the sound pressure. 10 dB + 6 db = 16 dB Changing sound levels are perceptible roughly proportional to the logarithm of the power ratio (P I / P O). Spreadsheet for HVAC systems racket and sound attenuation calculation. Audio calculator sections. (Circular or Rectangular) Table 3a: The attenuation of mitred bends with short chord turning vanes or no turning vanes. The splitter / attenuator key goes programmed regarding your individual requests. Long coax cable: Loss 3 dB attenuation (reduction to half the level) High power 10 watt amplifier: Gain=30 dB (increase in signal level by a factor of 1000 times. Software Prosilencer is a program for sizing and selection of sound attenuators. E ür6ûÂ¥w ªSÆ`‹ù7èÄ£IÕ÷5 ?+yÐŽU7Ïë2UËD FK‘H( rê Ií»NKP^>Z‚n0D €dM ¢&Æx )‘cÈø(gpý+Nm³æ>n±²Ý¨ÅºÎ3ã6 Nsm. 1. Common source treatments include noise-attenuation control valve trims, inline. Solutions. We would like to show you a description here but the site won’t allow us. The restriction of the attenuator is defined in Pa of static pressure loss. kbe@kbeinternational. wg. Helmholtz resonators excel in muffling sounds when designing concert rooms or studios. The platform is built as a Microsoft Excel Add-In and contains tools for common acoustics calculations, mainly centred around mechanical noise, simplified environmental noise, and basic room acoustics. 4 mm; 1 ft = 0. sound attenuator calculation excel. Adjustable Attenuator. txt) or read online for free. Example - Sound Power Level. Heat exchanger load calculation. 4 Sound Attenuators 7- DUCT TRANSITIONS There are Three Distinct Stages to the Noise Control Process: 1- Source 2- Transmission 3- Reception It is correct, though impracticable, to propose that noise can be controlled at any of these stages. For sources of significant size, sound pressure levels must be input at source-to-receiver distances large enough to be sufficiently in the far-field , where inherent directivity is minimal. Lp = Sound Pressure (assumed to be equivalent to the mean time-averaged sound pressure level. Shop. How to calculate heat load for a house. For example, a manufacture might specify that 25 dB (A) reduction is obtainable at 10 feet, a 10 dB (A) reduction at 1 meter for so. Sound attenuation Sound attenuation is specified to ISO 7235, i. attenuator followed by a 6 dB attenuator provides 16dB of attenuation overall. 1/1 = 0. The Lay-In Service Reduces Project Risk. The formula is as follows:Range, mean and standard deviations for sound attenuation rates for confined bubble curtains achieved on WSDOT projects. Support & Software Software ProSilencer ProSilencer Software for sound attenuator selection. 1/08/2019 12:29:00 AM. Read more Product Documentation. Duct Noise Calculation Excel Sheet - Sound Attenuation Download : Duct Noise Calculation Excel Sheet - Sound Attenuation. R 2 = Z o /2 [10 dB/10 – 1] / [10 dB/20]. The “K” factor, also known as the “impedance factor” is commonly used with attenuators to. The word attenuation is used across many scientific disciplines and can refer to the gradual reduction in the strength of sound waves, seismic waves, light, electrical signals, and more. March 13, 2022. It's free to use, and you can email yourself the results. The ASJ model as defined in Equation 7 has been implemented in an Excel spreadsheet to calculate the expected sound propagation along the validation test. These attenuators deliver good acoustic attenuation properties across a broad spectrum of sound frequencies while maintaining low air flow pressure drops through the attenuator. Attenuators can be fixed, fully variable or variable in known steps of attenuation, -0. When sound propagates in such media, there is always thermal consumption of energy caused by viscosity. Airlfow regenerated noise 3. Expressed in dB: 20 x log (0. The higher the rating, the more effectively the HPD will reduce noise exposure. 249) Multiply the total of above by a safety factor of 1. Find the % of a total: Put the total in column A and number completed in B. Sound Power from Sound Pressure. And the brand name. Calculation of the sound level L 2, which is found at the distance r 2: Reference distance r 1 from sound source m or ft: Sound level L 1 at reference distance r 1 dBSPL: Search for L 2: Another distance r 2 from sound source m or ft: Sound level L 2 at another distance r 2 dBSPL: Sound level difference Δ L = L 1 − L 2 dB Most manufacturers of generator enclosures, therefore, standardize on certain levels of sound attenuation at some predetermined distance. xml ¢ ( ¬UËNë0 Ý#ñ ‘·¨q¹ „PÓ. An attenuator is an electronic device that reduces the power of a signal without appreciably distorting its waveform. This chapter provides basic sound and vibration principles and data needed by HVAC system designers. What is the best sound attenuation product you will recommend. Manually calculating simple L-pads and especially step attenuators to meet this condition can be, in a word, challenging. A duct, shown in Fig. Estimate the Sound Power Level from the Fan - LN Enter the manufacturer's sound power data or calculate the fan sound power. 63 15 17 78. Download Free Arabic and Kufi SHX AutoCAD Fonts. Acoustics — Determination of sound power levels of noise sources using sound intensity — Part 3: Precision method for measurement by scanning. sound attenuator calculation excel. Sound - Attenuation and Speed vs. R = (12. The aim of this program is to assist engineers to design HVAC systems for commercial and industrial buildings. Request an Estimate. The equation that gives an approximation of sound power from the sound pressure of a noise source is: Lw = Lp + 10*LOG (A/A0) Where: Lw = Sound Power Level. The pressure ratio formula is: PR = P. e. This excel sheet calculates the noise attenuation for air ducts in air conditioning and ventilation systems like air ducts, VAV boxes, air terminals (diffusers), etc. Now you're done with your resistors! The values should be R₁ = 76. As an added bonus, the results are modifiable and can calculate the other values. DZ-3 sound attenuators provide very efficient attenuation in the 500 to 4000 Hz frequency range. attenuation of duct and fittings, sound power splits, end reflection, insertion loss of insulated duct and fittings, system component generated noise and critical space / room. P, CC series circular attenuators priate) sound attenuation effects from the unit sound power (Lw). In this case: (33 - 7) / 2 = 13. source off maximum sound pressure level = nr 40 table 1 room and terminal effect fig. Microstrip Characteristic Impedance Calculator Using a Formula by Brian C Wadell Used for calculating the Zo of PCB transmission lines, showing the formula used. We are HVAC noise control experts. SOUND ATTENUATOR 21. The sound wave generated by these sources transfer its energy throughout the duct and to the occupant’s area as shown below. Sound level, loudness, and sound pressure are not the same things. Access Acoustic Calculator More technical support below Tools. NO. , lumped element systems. Read More. xls), PDF File (. Pressure Loss Spreadsheet. Ensure the sound attenuators are installed in the direction of airflow and as per approved material submittal. The model consists of purely acoustic finite elements. Download HVAC sound. The benefit of expressing signal strength (power) in dBm is: we can express both very large and very small power values (W) in a short range of number. Software also calculates the. Software also calculates the. Lp1 - sound pressure level at location 1 (dB) R1 - distance from source to location 1 (m, ft) R2 - distance from source to location 2 (m, ft) Example -. Spreadsheet for HVAC systems noise and sound attenuation calculation. d 2 = m = ft. Address: 6122 Benjamin Road Tampa, FL 33634Speed of sound in water at temperatures ranging 32 - 212°F (0 - 100°C) - Imperial and SI units. Attenuators are also known and referred to as duct silencers, sound traps or mufflers. We also undertake sound attenuator. The dBmap. The rating shows how effectively a device attenuates external noise. Original number is in A and the percentage to reduce by is in B. Attenuator Pressure Loss A sound attenuator restricts the passage of air flow through it. ) The silencer should not be included in the initial calculation. About this calculator. Typically, it is assumed to be equal. sound attenuator calculation excel. NF EN ISO 9613-2 Acoustics -- Attenuation of sound during propagation outdoors -- Part 2: General method of. Sound attenuator calculation excel. FUNCTIONS THAT HAVE NOT BEEN REPLACED ARE: Calculation of the whole duct system Cross-talk External noisE In this paper, a new open source acoustics calculation platform, Trace, is presented. Reading Borough CouncilSelect Your Language. 2. 4K 39. Calculating sound intensity with the inverse square law. 10. Noise and Attenuation Noise is usually defined as unwanted sound - noise, noise generation, silencers and attenuation in HVAC systems. Roomside. An attenuator can be symmetrical or asymmetrical in form and either balanced or unbalanced. The attenuator should match source and load impedances in addition to the desired attenuation. To avoid noise breakout problems the duct attenuation taken should be limited to approximately 15dB. Download 4 Types of Excel Calculator's. 5 63 125 250 500 1000 2000 4000 8000 LEQ (dB) 79. The operation principle of the reactive silencers is a combination of lambda/4- and Helmholtz-resonators. Download ASHRAE Heat Load Calculation Excel Sheet XLS. Then, the apical diffraction attenuation of reflected sound equivalent source S 1 between the sound source and the sound barrier is calculated in the same way. Add point sources, screening barriers, buildings and decibel receiver points with detailed frequency information. Calculating percent difference between 2 columns. 03 System effect Fresh air louver 0. In those cases, once sound engineers identify a problematic frequency, they design the proper resonator that absorbs that particular tone. for HVAC Systems. 2 40. This is the type of attenuator Nuuk describes on his excellent website to use with his Gainclone (pre). The load impedance must be used in place of speaker impedance, and can be any value desired. Download Free MEP Calculation Excel Sheets, AutoCAD Drawings, and Training Courses for HVAC, Firefighting, Plumbing and Electrical Systems Design. The Attenuators “K” Factor. Gentlemen, may I turn your attention to an Excel spreadsheet I created for the calculation of resistor values for stepped attenuators in shunt (i. 1 PurposeThis article aims to provide a detailed explanation of sound attenuator calculations, including the concept, factors affecting sound attenuation, and the calculation methods used. To calculate the airflow needed in a room, the pressure and temperature. The noise rating graphs for different sound pressure levels are plotted at acceptable sound pressure levels at different frequencies. Download. In its simplest form, a. where η is the dynamic viscosity coefficient of the fluid, ω is. Airtight construction shall be provided by use of a hichaf1dbchaf31505lochf1 duct sealing compound on the job site, contractor shall supply material and labor par }pard ltrparql li720 i0keepkeepn owidctlpar x0wrapdefaultfaauto in0. Duct Noise Calculation Excel Sheet – Sound Attenuation. Typical value for speed of sound is 343 m/s for temperature 20 o C. Sound Attenuator The use of Sound Attenuators that are accurately rated under operating conditions is a matter of prime importance for achieving effective and predictable noise reduction as well as substantial savings over conventional methods. The formula for determining fres: sound attenuator calculation excel. A backup generator set is an important line of defense for business owners. In analyzing sound propagation in ducts it is customary to simplify the problem into one having only two dimensions. Formula. etc. Roomside Calculation Sound Attenuators Tel: +974 44 500 118 - 44 500 119 - Fax: +974 44 500 117 - Doha, State Of Qatar DUCT VENTILATION AIR CONDITIONINGCo. Sound power levels or LwdB are determined by the following formula: LwdB = 10*Log10 (Lw/ LR) The reference power LR is one trillionth of a Watt or 10 -12 W. Ventilation Systems - Acoustic Calculation ProcedureMar 15, 2019 - Discover (and save!) your own Pins on Pinterest. com. The software allows the prediction of stacks directivity, of atmospheric sound absorption. 13. àÞå øcO S¿ä1¥ý{Æn‹ j UÍ&/gÎ9sfžÌVÖTKˆ¨½kØu=f 8é•vmÃ^_þ nY…I8. (1) can be transformed to express the difference between the received sound pressure level and emitted sound power level - the attenuation - as: Lp - LN = 10 log (D / (4 π r2. 5k ohm. Flexible Sound attenuator The Splitter / Attenuator Product Key. Reflective or Reactive silencers. Learn how to select the right sound attenuator for your project and benefit from. Its required insertion loss is the positive difference between the estimated resultant soundAcoustic Solutions - SAFIDIf you are looking for effective ways to reduce noise and improve air quality in your building projects, you may want to check out the acoustic solutions offered by SAFID. - where one value is a reference value. Then your percent change formula takes this form: = (C2-B2)/B2. Author: BCHF Last modified by: 160745 Created Date: 11/1/1999 8:09:00 PMWe would like to show you a description here but the site won’t allow us. ) 7 1. 03 Sand trap. You do the calculations and you get odd results. Spreadsheet for HVAC systems racket and sound attenuation calculation. 00002 Pa. temperature and frequency. An attenuator is. In the ZS box, type a value of 75 Ω. In order to further optimize the sound attenuator with regard to pressure drop, a part of the sound attenuator’s active section has been arranged outside the connection. etc. Install the sound attenuators in line with ductwork as per approved drawings. Directivity coefficient - D. 27 Volume damper Volume damper 0. Stud Type. 5dB, -1dB, -10dB, etc. There are two calculators, one to determine the values needed to obtain a given attenuation, and the other to work out the attenuation of a network you may find in a commercial (or DIY) crossover. A), Zallaq Sofitel resort ( Bahrain), command of military works ( Abu Dhabi schools), etc, are some of the few projects amongst many. There will also be an option at the end to download your U-value calculation result and BIM files. In this article, we will show you how. The sound attenuation in a rectangular 600 x 600 mm unlined duct is 0. Download ASHRAE Heat Load Calculation Excel Sheet XLS. Download HVAC sound and vibration Download HVAC system noise In analyzing sound propagation in ducts it is customary to simplify the problem into one having only two dimensions. to rate indoor noise like noise from air-conditioning equipment and similar. no. Sound attenuators are essential devices for reducing noise in HVAC systems. Bends provide attenuation as shown in Tables 3a and 3b. Also it enables designers to design sound attenuation for masonry wall rooms. Description. L. Download Free AutoCAD Blocks for HVAC Systems Design dwg. The ASJ model as defined in Equation 7 has been implemented in an Excel spreadsheet to calculate the expected sound propagation along the validation test. 2 Hz, and a static compression of 20～52 mm. To calculate the percent difference between two numbers correctly, carry out these steps. xls / . 1 SILENCER TERMINOLOGY OVERVIEW In a HVAC system, the potential noise sources are AHU, terminal units and room air outlets. 3 71. You have to create then an excel sheet for price calculation. Watch. 2. Heat load calculation formula australia. It is a very wide range, so, to handle these quantities more easily the unit usually used is the decibel (dB), which is a logarithmic scale relative to a reference level. Single, Double or Triple. Duct Noise Calculation Excel Sheet - Sound Attenuation. Please note that a key must contain ALL options and indication that you will be able then to calculate a price having only the code. ProSilencer is the follow-up to ProAc, however not with the exact same functionality. Sound pressure and sound power are best explained with an example. Develops templates for repeat projects. It shall include the following modules: AX-01, AX-02, AX-03, AX-04, AX-06 and AX-07. In analyzing sound propagation in ducts it is customary to simplify the problem into one having only two dimensions. Quite often, microwave engineers refer to the one-dB compression point, but two or three dB compression points are often important in power amplifier chains. Helmholtz resonators excel in muffling sounds when designing concert rooms or studios. 27 Volume damper Volume damper 0. Signal’s power level lower than 1 mW has negative dBm values, and the signals stronger than 1 mW have positive dBm values. Attenuation Estimate the attenuation in the system. Despite the stated NRR of 33, then, wearing the earplugs would only reduce noise exposure to an estimated 87 dB. The sound wave generated by these sources transfer its energy throughout the duct and to the occupant’s area as shown below. 9/12/2018 10:36:00 PM. Today. 28, 2001 Elementary Manual Ashrae. Sound Pressure Sound Pressure is the force of sound on a surface perpendicular to the propagation of sound. The total signal level in decibel from equal signal sources can be calculated as. 6 Return duct Sound attenuator Fire damper Sound attenuator 0. Support & Software Software ProSilencer ProSilencer Software for sound attenuator selection. 95 shares. 125 32 34 77. Lebanon - Naher El Mott, INDUSTRIAL CITY . What is Total Attenuation? Total Attenuation refers to the combined effect of various factors that cause a reduction in the intensity or strength of a signal as it propagates through a medium or along a transmission path. A. Calculate how many square metres of Louvre your building requires using the CS Louvre Area Calculator. Sound Frequency and Air Humidity The speed and attenuation of sound in moist air. Moustafa M. 1. The Pi attenuator consists of one series. Description The attenuator housing is made of galvanised sheet steel. Sound level calculation To calculate the relevant sound level the attenuator sound reduction must be substracted from the fan sound level. References 1 and 2 are herein referred to as ISO/ANSI1,2. 9/12/2018 10:36:00 PM. Performance parameters are installed for all signal op amps. Acoustic Enclosures / Acoustic Cabins. In the ZS box, type a value of 75 Ω. 8 Ω. 2. K = attenuation ratio - 1. The L-pad Attenuator is a simple resistive voltage divider network which can be used as a fixed passive attenuator to reduce the amplitude of a signal. The distance from person 1 to bus stand is RΓéü = 10 m. Note - Sound and noise usually are not pure tones. R = ( k * V) / ( T - (k * V) / A )Noise Attenuation in Rotary Heat Exchanges Sound attenuation vs. Roomside Calculation Sound Attenuators Sound attenuators are essential devices for reducing noise in HVAC systems. Add Safety factors Add safety factors - 3 dB is recommended. 35 dB/m) = 3. For a particular volume knob setting on my sound card embedded with a headphone pre-amplifier, I would like to determine the output in dB SPL from the headphones. 2 ScopeThe scopeWA reduced = reduced sound level in dB(A) using an attenuator. Input Voltage is the voltage level at the input of the circuit or system. Tag: duct, duct noise, duct noise calculation, noise, sound, sound attenuation. (), was used to calculate the attenuation of plane waves traveling in a waveguide in Sect. 3 kPa) Lp = 20Log(101,300/0. Elsayed. Sound power level attenuation in an elbow is caused by sound reflection. sound attenuator calculation excel. 1 of LAA• All Sound Attenuator units are designed to ensure airtight operations with low leakage factor of + 3 %. In its simplest form, a sound attenuator consists. The noise is determined by: air velocity duct size (cross. d 1 = m = ft. Download Electrical Load Calculation Excel Sheet. Its available to use on all versions of Microsoft Windows. Use in areas with potentially explo-Exposure calculators and ready-reckoners. I played out a calibration tone of 1 kHz of peak amplitude 1 V (RMS 0. A calculation is then used to convert the measured sound pressureand attenuator airways. But before we look at T-pad Attenuators in more detail we first need to understand the use of the “K factor” used in calculating attenuator impedances and which can make the reduction of the maths and our lives a little easier. 00002) = 194 dB RE 20µ Pa Note: 20µ Pa is another way to write 0. Suppose you have the last month prices in column B and this month prices in column C. 1 First adjust the given sound level by the A weighted adjustments given in Chp 3, Table 3. You have to read ISO 12354 standard. Attenuation in lined and unlined ducts at different sizes and frequencies are indicated in the table below. Use the calculator below to calculate the sound pressure level at distance. sound attenuator calculation excel. Give it a try!NRR Calculator Details. The restriction of the attenuator is defined in Pa of static pressure loss. Fans Static Head Calculation Sheet - Free download as Excel Spreadsheet (. Glass Performance. 083 or . The attenuation is measured in decibels (dB), which is a logarithmic unit of measurement that expresses the ratio of two values. We would like to show you a description here but the site won’t allow us. The proportion of sound absorbed by the surface is called the sound absorption co. Touch device users, explore by touch or with swipe. Hearing protection calculators. 8 dB 72. Above the cut-on frequency, the shape of the wave front is no longer plane, and a good attenuation can be easily achieved by placing absorbing material on the duct walls . then at distance. . The two basic approaches for controlling valve noise are source treatment and path treatment. All Sound Attenuator units are designed to ensure airtight operations with low leakage factor of + 3 %. At some power level, the gain response of the device will become reduced by a specific amount. Download Free AutoCAD Blocks for HVAC Systems Design dwg. Real World +4 dBFlexible Sound attenuator The Splitter / Attenuator Product Key. 8 dB . 4 Safty factor 10% Plenum 0. Bends provide attenuation as shown in Tables 3a and 3b. Engineering Noise Control (4th Edition) Theory and Practice. 1, is assumed to be infinitely wide (in the x dimension) and to have a height in the y dimension equal to h. Email: [email protected] would like to show you a description here but the site won’t allow us. Now we add all of these values together, log this value and multiply it by 10 to give the final dB (A) value. Flexible Sound attenuator The Splitter / Attenuator Product Key. Many installations require attenuation at paths of sound transmission such as radiator discharge and ventilation air intakes. It is an essential tool for architects, engineers, and designers who need to ensure that their building design meets acoustic requirements. xlsx. What is the best sound attenuation product you will recommend. L N = 10 log 10 ((0. Pi Attenuator Calculator for Excel. To avoid noise breakout problems the duct attenuation taken should be limited to approximately 15dB. Select "Unequal impedances" in the "Circuit type" box. Plenum as sound attenuator. Hi friends I am still struggling to understand the math behind ladder attenuators. Based on Excel, with an interface in French or English, the acoustic calculation software SILDIS ®, published by ITS (*), allows the prediction of the performance of many products and construction systems for soundproofing: in term acoustics, and when applicable, in terms of aeraulics. These broad data opinions usually represent an average rating for the. Check out more useful information about the distance attenuation calculator and get the manual steps to calculate the. (10 m) (0. LW is the power specified in Watt. Pasternack's RF Free Space Path Loss (FSPL) Calculators is the ideal measurement tool that allows loss or attenuation of signal strength calculations between two antennas. Because of their long time experience with KNC’s HVAC equipment vibration and architectural noise separation products and. Calculating A weighted sound level for a given spectrum of sound levels A-Weighted Sound Level f (Hz) 16 31. The Sound Attenuation Calculation Formula is a mathematical equation used to determine the ability of a material or system to reduce sound transmission. xlsx), PDF File (. Related Documents NC - the Noise Criterion Noise Criterion - NC - level is a standard uesd to describe the relative loudness of a space within a range of frequencies. door air loss duct weight & flange drilling pressure loss spreadsheet sound attenuation spreadsheet preliminary pipe. LW is the A-weighted sound power level of the air-regenerated noise in the duct at the attenuator outlet level, applicable to B x H = 1 m2. Some of the calculation results are comparable with some input data envisaged in standardized calculation: cf. Calculation of the sound level L 2, which is found at the distance r 2: Reference distance r 1 from sound source m or ft: Sound level L 1 at reference distance r 1 dBSPL: Search for L 2: Another distance r 2 from. Attenuator calculator PI Attenuator calculator T Bramham matching transformer Butterworth filter designer Cascaded Noise Figure calculator. The disruption of the sound pressure wave and the reduction of noise is called attenuation - Sound Pressure Level vs. 1 / 1) = -20 dB. Elsayed , he illustrates the sound, vibration and noise problems in HVAC systems and their solutions with examples. Typical applications are air conditioning ductworks, cooling towers, ventilation systems. Duct Noise Calculation Excel Sheet - Sound Attenuation. Sound level, loudness, and sound pressure are not the same things. كيفية حساب تخفيض مستوى الضوضاء في أنظمة التكييف، و إختيار كاتم الصوتThe tool below allows for calculation of the Lw of Industrial Generators (excluding the driver) based on the calculations in Engineering Noise Control. 3. The decibel (dB) is a logarithmic unit used to express the ratio of two signal values - like power, sound power or pressure, voltage, intensity etc. The sound attenuation in 10 m duct is. Calculate the loudest possible sound at standard atmospheric pressure (101. Airmaster is a renowned Sound Attenuators Manufacturers, approved by leading consultants in the region for various prestigious projects such as king saud university (K. The sound wave travels along the z direction (out of the page) and its sound pressure can be. The formula to calculate sound attenuation over a distance for a line source is: Lp (R2) = Lp (R1) - 10·Log10(R2/R1) Where: Lp (R1) = Known sound pressure level at the first location (typically measured data or equipment vendor data) Lp (R2) = Unknown sound pressure level at the second location. Signals - Adding Decibels The logarithmic decibel scale is convenient when adding signal values like. Selecting the proper Panl-Flow® Silencer will ensure adequate and economical sound attenuation for your. R1 = Distance from the noise source to location. B&K | Sound and Vibration Measurement | Brüel & KjærUse Excel as your calculator. IAC Acoustics Duct Silencer Catalog-2LR--. Some of the calculation results are comparable with some input data envisaged in standardized calculation: cf. 00002 Pa. The quietest fan powered terminal in the market is the TFS-F Fantom IQ™. Program for HVAC methods noise and sound attenuation calculated. Standard Construction Sound attenuator casing is constructed with 1mm pre-galvanized sheet steel with mastic filled Pittsburgh longitudinal joints. Δp tot =p s1(I) −p s1(II) (1. In this example , the following 1:1 octave bands have been measured: Frequency Hz 63 125 250 500 1000 2000 4000 8000. This pdf document introduces the features and benefits of various acoustic products, such as acoustic panels, acoustic baffles, acoustic doors and acoustic. scribes the measuring of sound attenuation as well as the measurement of minor loss coefficient. The sound pressure measured twice as much gives 6 dB more level. 2 56. A = Measurement Surface Area of the Source. By: Moustafa M. Under the condition of free sound field (free space), the sound wave of the point source follows the spherical divergence law, and the sound power level is used as the point source evaluation quantity.