声学楼论坛信息发布区自由交流室 → 外行支持阿龙-翟的实效频宽论


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主题:外行支持阿龙-翟的实效频宽论

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  发帖心情 Post By:2009-7-31 13:39:08 [显示全部帖子]

友情引用管老师的话:

“如果一个学生的考试成绩很不好,说他是个好学生也是不对的,好学生的分数也不能太低。同样,如果电声器材的物理测试结果很差,那么这台设备就肯定是不好的,没有必要再作听音评价。”







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帅哥哟,离线,有人找我吗?
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  发帖心情 Post By:2009-7-31 15:24:29 [显示全部帖子]


至于实效频宽,并不是严格概念。再友情引用一段:

21.2 Effective frequency range
21.2.1 Characteristic to be specified
The range of frequencies, bounded by stated upper and lower limits, for which the frequency
response of the loudspeaker in accordance with 21.1.2, measured on the reference axis with
a sinusoidal signal is not more than 10 dB below the sound pressure level averaged over a
bandwidth of one octave in the region of maximum sensitivity or a broader bandwidth stated
by the manufacturer, shall be specified. Sharp troughs in the response curve, narrower than
1/9 octave (one-third of 1/3 octave) at –10 dB level shall be neglected in determining the
frequency limits.
21.2.2 Method of measurement
The effective frequency range may be obtained from the frequency response described in
21.1.1, measured with sinusoidal signals only.
21.3 Transfer function
21.3.1 Characteristic to be specified
The sound pressure amplitude level and phase versus frequency shall be specified, measured
under free-field or simulated free-field conditions, at a stated position with respect to the
reference axis and point, for a specified constant voltage at the loudspeaker terminals. Unless
otherwise stated, this voltage shall be 1 V.
The signal level used shall ensure that the measurement result is unaffected by non-linearity.
The sound pressure amplitude level is normally expressed as the equivalent sound pressure
level. In presenting the phase as a function of frequency, phase shift related to propagation
delay between loudspeaker and microphone shall be removed.
21.3.2 Method of measurement


这后面就无所谓了——按某些人的说法,怎么测试无所谓,觉得好就是好了。


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  发帖心情 Post By:2009-7-31 19:39:17 [显示全部帖子]

回“相对论”:

    如果经验主要限于录音行业,在这里倒的确是外行了。当然,有您捧一捧,阿龙会很感动,心情会很好。票友之间也可以惺惺相惜么。但是也仅限于心情了。

    电声的问题在于门槛低,人员良莠不齐。叫个外行做显示器,怎么都不会亮;但是叫个外行做个音箱,怎么都可以响。现阶段大家要求不高,能响就行了,于是满街都是“大师”、“奇才”。当然,不论谁都能评价几句“音质”;好多人爱屋及乌,仿佛对硬件和理论也懂行。结果发展出好多“声学”评论家,都是“懂设备”的人。其实,因为这个就觉得自己能谈理论、谈测试,就错了。你所说的,工程师天天都在想。你以为是模糊的地方,行业内其实讨论过;而且很多已经讨论明白了——如谐波测试。你说不好测的东西,其实已经有人做过测试,且发过文献了——如主客观指标的对照。


    生活中您可能做甲方习惯了,生活中也是乙方满足甲方。但是技术的事情,该怎样就是怎样,不随甲方好恶而有所变化,正如它不随阿龙的“评测”而变。按照阿龙跟您的电声技术跟理论修养,在这里只能被拍。不管声学楼里有多少不专业的人,它始终是个专业论坛。

 


 

[此贴子已经被作者于2009-07-31 21:54:07编辑过]

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