耳机佩戴对声音的影响

2019-07-30 00:32 作者:鬼斧神工119 0人读过 | 我要投稿

前几天的文章提到，对于音箱系统而言，由于音箱的SPL受到房间和自身影响，在空间中的分布也不同。在一般的房间内，即便在比较标准的听音位（等边三角形顶点），人头位置轻微变化（1~4cm，例如换器材前后两次所做的位置略有不同）可以在某些频段引起约1~2dB的差别，以百分比计，这约为不同RCA信号线之间差别的200000倍。

而对于耳机而言。前后两次佩戴的轻微差异同样会引起可闻的差别。其实业内有两篇经典的研究。

Scientific listening tests on headphones are difficult to conduct owing to the challenges in controlling listening test nuisance variables and their inherent biases. They include sighted and tactile biases, leakage effects, consistent fit across listeners, and auditory memory loss accrued from large time gaps between comparisons between different headphones. This is particularly challenging for in-ear (IE) headphones where a good seal is needed for good bass performance below 500 Hz [1].

科学的耳机听音测试是很难进行的，因为在控制听音测试时会受到讨厌的变量和人们固有的偏见的挑战。它们包括视觉和触觉的偏差、漏泄效应、听者之间的一致性以及切换不同耳机之间的时间间隔过大而导致的听觉记忆丧失。这对入耳式耳机尤其具有挑战性，因为在500赫兹以下的低音性能需要良好的密封环境。

在之前的虚拟耳机讲解中就曾提到泄露对于耳机声音的影响，我也经常在我的测评文章中提到泄露的影响，那么这种影响究竟有多大？

Headphone leakage effects can have a profound effect on low frequency performance of headphones. Deviations of 20 dB or more in the headphone response can easily result from varying amounts of leakage.

耳机的泄露效应会对耳机的低频表现产生很大的影响。对于不同程度的泄露很容易产生20dB以上的差别。

耳机泄露效应的基本原理相对简单易懂。当耳机戴在头上时耳罩创造了一个封闭的环境。泄露多多少少都会存在，在有些极端情况下，泄露。

So-called “open back” headphones do not include an acoustically impermeable barrier behind the driver, and thus have a large leakage component.

所谓的“开放式”耳机在耳机单元后面没有隔音屏障，因此本身就具有较大的泄露。

Leakage effects are very difficult to fix using any type of fixed electrical filter. If the headphone has poor fitment and high leakage then it often can have highly variable low-frequency response for even a single user. In other words, the response is not consistent as the user moves them around on their head, or from user to user.

泄露效应无论用任何固定的滤波器都难以修复。如果一个耳机的佩戴较差并且泄露较高，那么它的声音在低频部分就会有较大的变化，即便是对于同一个用户。换句话说，当耳机在用户的头上移动到不同位置时，或者对于不同的用户而言，耳机的响应都是不同的。

其实以上内容我在我一年前的第一个live里就有相关描述。

The leakage effects caused by an incomplete seal of the cushions to the head can be particularly difficult to account for. Differences in head shape/size, pinna size etc. can interact with the headphone yoke and cushion mechanical design in a complex manner. Commonly used measurement techniques are not well suited to measuring real world leakage. Some methods which use a flat plate or conical shaped fixture [5], attempt to eliminate all leakage in the interests of repeatability. This works best for headphones with little or no inherent leakage, but will over-represent bass output for many other headphones.

这段。。我真的不想翻译了，我懒。。。

每个耳机内均装有微型麦克风，测量耳机在实际人耳内的响应。仅测量在50Hz~2kHz的频响。

Each headphone was measured at the blocked canal of each subject 6-8 times, over two measurement sessions on separate days. Subjects removed and replaced the headphones for each measurement repeat and were instructed simply to put the headphones on as they normally would.

每款耳机在每名受试者已经堵住耳道的状态下测量6-8次，在不同的日期进行两次测量。受试者在每次重复测量时都会取下并更换耳机，并且只需按照正常的方式戴上耳机即可。