Acoustic test according to the standard 9614-2 根据标准9614-2 的声学试验
Acoustic environment: 声音环境
The acoustic environment should as much as possible stay the same during the entire test. It is also important to reduce the extraneous intensity as much as possible before the test to insure as little variation as possible and a better quality in the measurement (disabling source of extraneous noise that are not necessary for the test, making sure the operator is aware of the problem of extraneous noise).
The extraneous noise should be more than 20dB less than the Lp measure on the surface.
在整个试验过程中，声音环境应尽量保持相同。 需要强调的是 ， 在试验之前应尽量降低外来声音强度以保证尽量小的误差和更好的测量质量（消除与试验无关的外来声源， 确保操作员意识到了外来声源的问题）。
外来声源应大于20dB， 但小于表面上测量到的Lp。
General test procedure: 一般的试验步骤
Criterion 1 Criterion 2
We have to follow this process to have a clear result. 我们应该按照以下程序得出明确的结果。
1. Measurement device
测量设备
To be able to proceed with this standard, we have to use an intensity device (expensive) as all the points and calculus refer to this kind of device.
为保证试验的进行， 我们应在所有点使用强度仪器（昂贵的）和与此设备相关的积分知识。
2. Evaluation of the temporal variation indicator
暂时变化指标的评审
After selecting a surface and separating it in segments, we measure the temporal intensity Inq (the intensity probe is in mode “instantaneous mode” for more than 100s (do not forget to note on the one-third octave band). Then calculate the temporal average intensity Inm, m=1 to M on a period T (see figure below). T has to be more then 1s and M is generally equal to 10.
在选择完子表面，并将其分为区段后， 我们测量其暂时强度Inq（强度探针处于“瞬间模式”下多达100s（不要忘记标注在1/3倍频带上））。 然后计算T（参见下表）时间段内暂时平均强度Inm, m=1到M。 T应多于1s， M一般等于10.
We then calculate the temporal variation indicator for different value of T and in increasing it by 0,5 or less using the equation:
然后我们计算不同T时间段内暂时的变化指标， 并使用以下等式逐渐增加0.5或更少。
With 且
And find the integration time TFT<0,6 that satisfy FT<0,6 然后发现积分时间TFT<0,6满足FT<0,6。
3. Definition of the measurement surface and segments: 测量表面和区段的定义
• • • • • • • • • • • • • • •
The measurement surface should be at more than 0,25m from the unit. 测量表面距离机组应大于0.5m
The length of each segment should be more than 0.2m. 每个区段的长度应大于0.2m
Use only straight line for the probe to have more accurate measure as we do it manually.
对于探针，应使用直线以得出比手动更加准确的测量。 The speed of the measurement shall be as constant as possible. 测量速度应尽量保持匀速。
Take particular attention to the opening as they should have a particular intervention in the measure.
着重注意开口， 因为此点将对测量产生极大的影响。
Put the unit on the ground and do not count this surface in the calculations. 将机组放置在地面上，不要将此表面包含在计算中。
The number of segment depends of the size of the surfaces. Each surface should be correctly segmented.
区段的数量取决于表面的大小。应对每个表面进行正确的分段。
The scanning road shouldn't be too long (not more than 1m) so the precision of the measure is not shot down by the displacement. It’s better to divide the surface in two.
扫描不能太长（大于1m），这样，测量精度不会因为移位而降低。 最好将表面分为两段。
To have better precision on the measure, it's better to keep the scanning road horizontal as much as possible (because we do the measurement manually).
指定表面的区段应在一个方向。为得到更加精确的测量，扫描路径应尽可能为横向（因为我们将手动测量）。
A drawing of the surfaces and the repartition of the segments on them shall be put in the report.
表面的图纸和区段的分布应包含在报告中。
• • • • •
(see the complement at the end for more information) 欲知更多信息，请参见文后的补充。
4. Determination of the scanning duration:
扫描时间的确定
For each surface element (composed of more than one segment), calculate the scanning minimal duration with the equation:
对于每个子表面（至少有一个区段）， 使用以下等式计算扫描的最小持续时间。
NS: number of segment on the surface element Ns： 子表面的区段数量
Put these values in the report. 将这些数值记录到报告中。
5. Criterion 1:repeatability of the measure
标准1： 测量的重复性
For each surface element, after having made two scans (finish a scan completely before doing the other), verify the equation:
对于每个子表面，在进行完两次扫描（在完成一个扫描后， 在完成另一个）后，验证以下等式
LIn(1): normal intensity level of the first scan LIn(1): 第一次扫描的正常强度水平
s: incertitude given by the following table. S： 下表给出的不确定性因数
One-third-octave band centre frequencies (Hz) 1/3倍频带中心频率（Hz） 50 to 160 200 to 315 400 to 5000 6300
Standard deviation s (dB) 标准偏差（dB） 2 1,5 1 2 6. Criterion 2: measuring device adequacy control 标准2： 测量设备适当性控制
For this criterion, we have to, first, calculate the pressure-intensity rate FpIn with the equation: 对于此标准， 我们应首先根据以下等式计算压力-强度率FpIn
With 且
• Lp: average acoustic pressure calculate by: • Lp: 以下等式计算出的平均声压
✓ ✓ ✓ ✓ ✓
• LIn average normal acoustic intensity calculate by: • LIn 通过以下等式计算的平均正常声强
p²j: average pressure on each segment p²j: 每个区段上的平均压力 p0=20µPa
N: number of segment N： 区段数量
✓ Inj: average normal intensity on each segment ✓ Inj: 每个区段上的平均正常强度 ✓ I0= 10^-12 W.m-2
We then calculate Ld with the equation: 我们应使用以下等式计算Ld
Where 其中：
• K is the bias error factor and for our grade of accuracy its value is 10dB • K 为偏移误差因数，对于精度级别来说，其值为10dB
• δpl0: difference between Lp and LI when the probe is placed so LI is null. The equation is: • δpl0: 当探针放置时，LI归零时， 比较Lp 和 LI 之间的不同。等式为：
We then compare Ld and FpIn for each frequency band. 然后，比较每个频率带Ld 和 FpIn。
7. Other important test: the non-returning indicator （negative）
其他重要的试验： 非回归性指数
For this test, we have, first, to calculate the Fp|In| with the equation: 对于此试验， 我们应首先使用以下等式计算Fp|In|
• • • •
Lp is the same as in point 6 Lp是相同与6中的Lp相同。
L|In| is the average normal acoustic intensity’s modulus’ level calculate with: L|In|平均模式声音强度的模块水平，通过以下等式计算：
✓ |In|j: normal acoustic intensity’s modulus’ average value measured on each
segment.
|In|j: 在每个区段上测量的正常声音强度模块平均值。 We can now make the calcul: 现在，我们可以进行计算：
The test shall be positive as the formula shows, and in this case, no matter how large the extraneous source is , it will not affect the measurements carried out after.
试验结果应如以上公式所示， 且在此情况下，不管外部声源的是大是小，它将不会影响到以后的测量。
8. Action to put in place if the different criterion are not accepted: 如果不同的标准不被接受， 应采取的行动
a. Action A: 行动A：
Augment the scan duration and/or reduce the temporal variability of the parasitic(interfering ) intensity or make the measure during a time with less variability
增大扫描时间和/或降低寄生(干扰)强度的暂时性变化， 或在很少变化的时间内进行测量。
b. Action B: 行动B
Modify the speed, duration and/or the path of the scan 更改速度，持续时间和/或扫描路径
c. Action C: 行动C
Modify the surface’s element and/or the measurement’s surface. 更改子表面和/或测量表面
d. Action D: 行动D
If there is some parasitic noise and/or of strong reverberation, reduce the average distance between the source and the measurement surface but it shouldn’t be less than 0,25m. Without any parasitic noise and/or strong reverberation, augment the distance between the source and the measuring surface but not more than 1m.
如果有寄生噪音和/或强烈的反射， 降低声源和测量表面的平均距离。但不应小于0,25m.如果没有寄生噪音和/或强烈的反射，增大声源和测量表面的距离， 但不应大于1m。
e. Action E: 行动E
Protect the measuring surface from the parasitic noise with a screen or take some action to reduce the acoustic reflection on the source.
使用屏保护测量表面免受寄生噪音的影响， 或采取一些措施，降低声源的反射。
9.
of it: 表面选择和分段
Selection of the surface and the segmentation
The surface measurement should be cubic and all surface’s elements have to be square: 选择的子表面应为立方体，表面应为方形：
The numbers represent the surface element. 数字代表了子表面
For the scanning, we take the surface element and we cross-rule it: 对于扫描，我们选择子表面并横断之。
1, 2: scanning rode
1， 2指的是扫描路径，3是区段。 3: segment
Δx,Δy: side of the segment. Δx,Δy: 区段边缘
The ratio of Δx and Δy have to satisfy the formula: Δx 和 Δy的比例应符合以下公式：
The longest side has to be less than half the minimal distance between the surface’s element and the source. On all the measuring surface, the ratio between the biggest segment’s area and the smallest should be less or equal to 1,5
长边应小于子表面和声源之间最小距离的一半。 在所有的测量表面上，较大区段面接和最小的区段面积应小于等于1,5。
All the results have to be compiled in the data sheet (only the approved measures are necessary). 所有的结果必须在数据表中编辑（只有批准的测量是必要的）。
