本帖最后由 vic0561 于 2023-5-28 21:10 编辑
看你的截图里面有我说过的听音能力这件事和个体的听力水平听音技巧听音环境等因素有关，我这个观点应该是客观的。下面给出一个例子，当然这件事听说过，但是不好完全确定真伪，因为没有得到权威资料的确认，但是Bart Locanthi 这个人应该是真的，我下面的例子似乎能够证明在几十人两万次不太普通的耳朵都听不出差别时，Bart Locanthi 应该算是为数不多真正的金耳朵了，当然他应该没听过电源线的差异。有特殊听音能力的人应该是有的，因为人人都有差异，极限能力和经验不同，起码理论上是存在这种可能的，能否找到是另一回事。当然一个产品要确定什么样的标准，以谁为目标客户，这是与商业策略成本等市场经济因素相关的事情了，例如音响电源线是否真的需要那么高的精度，这个也与商业因素有关，和欣赏音乐关系我看就没有那么大。我泡家电论坛找乐之余也是力图提供一些有意义的信息。
故事如下：
"A good example is the listening tests conducted by Swedish Radio (analogous to the BBC) to decide whether one of the low-bit-rate codecs under consideration by the European Broadcast Union was good enough to replace FM broadcasting in Europe. Swedish Radio developed an elaborate listening methodology called “double-blind, triple-stimulus, hidden-reference.” A “subject” (listener) would hear three “objects” (musical presentations); presentation A was always the unprocessed signal, with the listener required to identify if presentation B or C had been processed through the codec.The test involved 60 “expert” listeners spanning 20,000 evaluations over a period of two years. Swedish Radio announced in 1991 that it had narrowed the field to two codecs, and that “both codecs have now reached a level of performance where they fulfill the EBU requirements for a distribution codec.” In other words, Swedish Radio said the codec was good enough to replace analog FM broadcasts in Europe. This decision was based on data gathered during the 20,000 “double-blind, triple-stimulus, hidden-reference” listening trials. (The listening-test methodology and statistical analysis are documented in detail in “Subjective Assessments on Low Bit-Rate Audio Codecs,” by C. Grewin and T. Rydén, published in the proceedings of the 10th International Audio Engineering Society Conference, “Images of Audio.”)After announcing its decision, Swedish Radio sent a tape of music processed by the selected codec to the late Bart Locanthi, an acknowledged expert in digital audio and chairman of an ad hoc committee formed to independently evaluate low-bit rate codecs. Using the same non-blind observational-listening techniques that audiophiles routinely use to evaluate sound quality, Locanthi instantly identified an artifact of the codec. After Locanthi informed Swedish Radio of the artifact (an idle tone at 1.5kHz), listeners at Swedish Radio also instantly heard the distortion. (Locanthi’s account of the episode is documented in an audio recording played at workshop on low-bit-rate codecs at the 91st AES convention.)How is it possible that a single listener, using non-blind observational listening techniques, was able to discover—in less than ten minutes—a distortion that escaped the scrutiny of 60 expert listeners, 20,000 trials conducted over a two-year period, and elaborate “double-blind, triple-stimulus, hidden-reference” methodology, and sophisticated statistical analysis?
大致说就是，瑞典电台设想用一种低码率的压缩格式来代替FM广播。为了确认这一压缩格式的声音是否足够好，他们做了广泛的盲听测试，牵涉到60个有经验的试验者（expert listeners）进行了总共20000次的“听”。最后盲听测试的结果似乎表明这种压缩格式不会对音质造成可闻的劣化。最后瑞典电台基于盲听测试的结果，决定采用这种压缩格式来播放。做出这个决定后，瑞典电台把一盘经过这种压缩格式处理的音乐磁带寄给一位专家——已故的Bart Locanthi。这位先生是数码音频领域内的权威人物。然而这位Locanthi没有采取盲听的方式，只是用传统的试听方式，10分钟内就发觉这种压缩格式其实是有损音质的，并且指出了它的具体失真。在他指出问题之后，瑞典电台的试验人员们马上也注意到了这个失真！
为什么一个有经验的听者，Bart Locanthi先生，能在10分钟内找出问题，而60个有经验的听者，按照严格的盲听原则，在2年的盲听时间中，进行了2万次的聆听，却无法找出这个问题？"
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狗仔卡
发表于 2023-5-28 21:07
