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Test Report No.:
30783046.003
Client:
MDG Computers Canada Inc.
2940 Bristol Circle, Oakville, Ontario L6H 6G4 CANADA
Test Object:
Desktop computer, “Tower”
Model No.:
Vx6850i; Vx6750i
Trademark:
-
Sample Ref. No.:
-
Serial No.:
prototype
Test Date and Location:
2007-10-26 TUV Rheinland Canada Inc., 1200 Sheppard Ave. East,
Suite 204, Toronto, ON, Canada M2K 2S5
Test Standard:
Test Result:
Page 1of 5
ISO 7779:1999 Acoustics - Measurement of airborne noise emitted by
information technology and telecommunications equipment
ISO 3744:1994 Acoustics – Determination of sound power levels of noise
sources using sound pressure – Engineering method in an essentially free field
over a reflecting plane
ISO 9296:1988 Acoustics – Declared noise emission values of computer and
business equipment
The test object described above
passed
;
failed
;
N/A
Tested by:
Reviewed by:
2007-10-29 S. Kraemer
2007-10-29
_____________________________________________
Date
Name
Signature
___________________________________________________
Date
Name
Signature
Other Aspects:
P. Morton
A-weighted sound power levels were determined according to clause 7 of ISO
7779:1999 from measurements of A-weighted sound pressure levels in
accordance with ISO 3744:1994. Declared noise emission values were evaluated
according to ISO 9296:1988
The declared A-weighted sound power levels were compared with the limits given
in the NMSO* specification section 7.0 (f) (i) as required by the client.
(* Canadian Federal Government National Master Standing Order)
The highest power model of a series was tested.
Attachment 1: Photographs
This test report only refers to the test sample described above and may not be duplicated in part without
the express permission of the Testing Centre. This test report does not permit the use of a test mark.
TEST REPORT NO.: 30783046.003
PAGE 2 OF 5
1. INSTRUMENTATION
Measurement Equipment
Sound level meter: Bruel and Kjaer model 2236
Calibrator : Bruel and Kjaer model 4231
Serial no.
Next calibration
2100721
2007-11-09
2130900
2007-11-09
2. TECHNICAL DATA
Description of test object
: Desktop computer, model number Vx6850i (tested);
Vx6750i (not tested, represented by Vx6850i)
Rated voltage and frequency
: AC115/230V 50-60Hz
3. TEST ENVIRONMENT
Description and dimensions
: Hemi-anechoic chamber, 8m X 4m X 4m high
Environmental correction K1
:
0 dB
4. ATMOSPHERIC CONDITIONS
Air temperature
Barometric pressure
Relative humidity
Wind velocity
:
:
:
:
25 °C
100.4 kPa
52%
not applicable
:
:
24 dB(A)
0 dB
5. BACKGROUND NOISE
Background sound level
Background noise correction K2
6. INSTALLATION AND OPERATING CONDITIONS
Description of placement and operating conditions: The equipment was placed on the floor in
the centre of the test chamber and operated under idling and operating (hard disk drive
accessing) conditions as required by the specification.
TEST REPORT NO.: 30783046.003
PAGE 3 OF 5
7. MEASUREMENT SURFACE AND MICROPHONE POSITIONS
10 microphone positions were located on the hemispherical measurement surface according
to ISO 3744:1994 annex B.1, with radius r = 0.5 m. The small radius was chosen because of
the low sound pressure levels to be measured.
COORDINATES OF MICROPHONE POSITIONS 1 - 10
[r = 0.5m]
Measuring point
x/r
y/r
z/r
1
2
3
4
5
6
7
8
9
10
-0,99
0,50
0,50
-0,45
-0,45
0,89
-0,33
-0,66
0,33
0
0
-0,86
0,86
0,77
-0,77
0
0,57
0
-0,57
0
0,15
0,15
0,15
0,45
0,45
0,45
0,75
0,75
0,75
1,0
TEST REPORT NO.: 30783046.003
PAGE 4 OF 5
Figure 1. Microphone array on the hemisphere
TEST REPORT NO.: 30783046.003
PAGE 5 OF 5
8. TEST RESULTS
Sound pressure level [dB(A)]
Microphone position
1
2
3
4
5
6
7
8
9
10
__
Surface avg. L’p
Idling
34.2
40.5
40.2
32.9
32.5
37.6
34.4
32.9
33.2
36.2
36.5
Operating
36.4
42.5
41.5
34.0
33.5
38.2
37.3
35.2
35.8
37.1
38.1
Condition
Measurement radius r = 0.5m
Measuring surface area, S = 1.6m2
Surface __
average L’p
Correction
K1
Correction
K2
Surface sound __
pressure level LpA
10 log
(S/S0)
Sound
power level
LWA [dB]
Idling
36.5
0
0
36.5
2.0
38.5
Operating
38.1
0
0
38.1
2.0
40.1
Condition
9. EVALUATION OF DECLARED SOUND POWER LEVEL
The declared A-weighted sound power level in bels is defined in ISO 9296:1988 as:
LWAd = 1/10 (LWA + K) [B]
where K accounts for measurement uncertainties and production variations. Since only one
sample (representative of a production batch) was submitted, K was estimated from values of
measurement uncertainty and production variation typical of computer equipment.
For a sample standard deviation of reproducibility SR = 1.5 dB and a sample standard
deviation of production Sp = 2.0 dB, the value of K calculated from ISO 9296:1988 is K = 3.5 dB.
The declared sound power levels for idling and operating modes are obtained by adding K to
the sound power levels determined above with the following results:
Sound power
level LWA
[dB]
K
[dB]
Declared Aweighted sound
power level LWAd
[B]
NMSA-specified
upper limit value
LWAd [B]
Result
Idling
38.5
3.5
4.2
4.5
Pass
Operating
40.1
3.5
4.4
4.8
Pass
END OF TEST REPORT