APPLICATION NOTE Sales & Application DEWESoft Slovenia

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1 Sales & Applicatin DEWESft Slvenia Abstract: This applicatin nte shws a measurement with DEWESft sund pwer measurement system and GRAS 67HA Hemisphere. The bject under test was a standard ntebk, the measurement was dne accrding t ISO 3744 in a semi-anechic chamber.1101 Key-Wrds: sund pwer, sund level, micrphne, ISO 3744, hemisphere 1. INTRODUCTION Test Criteria - Nise Emissin We use a nise level gauge (Vltcraft SL-300 r similar) and a standard test setup t measure the emissins f a test mdel. The gauge is fixed 15 cm frm the ntebk and is secured against vibratins emanating frm the test mdel. The measurements are taken in db(a) (Decibel). The fllwing are ur test categries: Idle Minimum: minimum nise emissin while laptp is idle (Windws pwer plan: "Energy Saving" Medium: Average nise emissin recrded while laptp is idle (Pwer Plan: "Energy Saving") Maximum: Highest nise emissin measured while the laptp is idle (Pwer Plan: "High Perfrmance") High System Use Medium: Average nise emissin while the cmputer is running at high level f system use. (3D Mark 2006, Pwer plan: Pwer Plan: "High Perfrmance") Maximum: Highest pssible nise emissin while the system is under heavy lad (Pwer Plan: "High Perfrmance", 100% CPU and GPU usage - thanks t Prime95 and Furmark) The fllwing may help the reader better understand the results:

2 In a quiet rm, the human ear can hear backgrund nise, which shuld amunt t arund 28 db. A cnversatin at a nrmal vlume ranges at 60 db. All these values are dependent n the distance frm the surce f the nise. This is why we fix ur gauge int place at a cnstant distance frm ur test mdels. This allws us t get clear results which can be cmpared with each ther. The measurements are presented graphically and can be judged subjectively: Under 30 db: barely audible Up t 35 db: audible but nt distracting. Ideal level f nise emissin fr a laptp running ffice prgrams. Up t 40 db: clearly audible, and might be distracting after a while Up t 45 db: might disturb the user if s/he is in a quiet rm. Still acceptable while playing games. Over 50 db: ntebk emissins ver this level are uncmfrtably lud 2. MEASUREMENT SETUP 2.1 Used equipment Data acquisitin system SIRIUSi-HD-ACC, USB-based 16 channel IEPE/Vltage unit Sensrs and transducers 10 micrphnes GRAS Type 26CA (scaling: -40/-55 mv/pa) GRAS 67HA 1m CCP hemisphere kit (diagnal: 2716 mm, height: 1283 mm) 10 BNC cables (10 meters) 2.2 Used sftware DEWESft X2 DSA package Sund Pwer plugin

3 2.3 Phts f setup APPLICATION NOTE 2015

4 2.4 Hemisphere kit setup We used the hemisphere kit frm GRAS with 10 micrphnes and a radius f 1.36 meters. The distance frm the sund surce t the micrphnes was 1 meter. The grid is very simple t assemble if yu fllw the attached instructin manual. It tk us apprximately 30 minutes t prepare everything. First we had t put tgether the metal sticks and attached them tgether, t get a nice hemisphere structure. The next step was t put the micrphnes in the right psitins accrding t the standards. The grid supprts 10 r 20 micrphnes, s we had t select the right psitin fr micrphne munting. The psitins had t be the same as in standards and they are already predefined with small screws f different clrs. We used 10 BNC cables that were 10 meters lng, s that measurement equipment was utside f the semi-anechic rm. This is very imprtant fr reducing backgrund nise t minimum. Micrphnes had TEDS chip, and were calibrated in the factry. The whle data acquisitin prcess tk us apprximately 10 minutes. We measured laptp in three different states and the minimum measurement time fr ne measurement is 20 secnds (accrding t standard). 2.5 Sund Pwer setup The accrding setup was chsen frm the drpdwn menu (ISO 3744, hemisphere), 10 micrphnes are munted arund the sund surce in 1m radius, in the table yu see the exact psitins (x, y, z). Barmetric pressure was measured and entered, the K1 (backgrund measurement) crrectin methd was additinally selected.

5 2.6 Measurement screen The SundPwer-Plugin in DEWESft guides us thrugh the prcedure. At first the backgrund nise measurement is dne, with sund surce (laptp) switched ff. Then the laptp is switched n, cnfigured t idle mde r high system use, and the measurement is perfrmed. Accrding t the standard data has t be cllected fr at least 20 secnds fr each step. The green actin buttns allw interactin (Acquire backgrund, start acquisitin). The text bxes belw shw status messages and warnings. On the left side there are the 10 ctave plts f all micrphnes, n the right yu see the three graphs f the result: n tp, mst imprtant: Sund Pwer, fllwed by Sund Level and the crrectin data. 3. RESULTS AND REPORT The nise levels f the 17-inch ntebk are very gd. It is always audible because the fan never stps spinning. The nise is very lw during idle at 32 db(a). In this scenari, the fan speed is mre r less cnstant and therefre very cnvenient fr ffice use. The hard drive can be a bit disturbing with the clatter f the read/write heads, we measured 37.6 db (A) during high activity. When we demand the highest perfrmance f the 17R, the nise rises up t 40.4 db (A) (stress test CPU+GPU-FurMark). When we just play a game r run 3DMark 2006, we measured a mderate 36.4 db (A). In these cases the speed f the fan is als cnstant and there is n annying pulsating.

6 SOUND POWER LEVEL REPORT Prject number: Prject descriptin: SPL f laptp with pwer supply Date f measurement: Cmpany: Dewesft d... Reprt versin: 1.0 Standard: ISO 3744 Lcatin f measurement: Respnsible persn: Dewesft Machine type: Laptp Machine descriptin: Length [m]: 0.27 Width [m]: Height [m]: 0.41 Fan speed [RPM]: 3963,00 Additinal infrmatin: Laptp was running under perfrmance test FurMark (same as in Appendix A) High-precisin sund pwer meter: Dewesft Measuring amplifiers: Sirius ACC Hemisphere: GRAS (1 m) Micrphnes: GRAS Data recrding and analysis sftware: DEWESft X2 SP3 Calibratr: GRAS calibratr

7 Micrphne psitin: hemisphere Radius [m]: 1 Number f micrphnes: 10 Type f rm: semi-anechic Weather: sunny Temperature [ C]: 22 Pressure [kpa]: 1000 Relative humidity [%]: 45 Measurement duratin [s]: 20 K1 [db]: 1,30 K2 [db]: 0,00 Sund Pwer Level [db(a)]: 40,4 Frequency [Hz] Lw (avg) [dba] , , , , , , , , , , , ,22

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