Measuring a portable audio device’s response to excessive sound levels
Measuring a portable audio device’s response to excessive sound levels
复制标题
测量便携式音频设备对过高声级的响应
DOI：
--
复制
发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Iain Jackson
中科院分区：
文献类型：
--
作者：
P. Kendrick;T. Cox;B. Fazenda;Iain Jackson
这是一份报告，详细介绍了如何进行一系列测量，以量化一系列便携式录音机的非线性性能。一系列常见设备的性能进行了量化，包括：大炮550 D，埃迪罗r44，诺依曼U87 ai通过Focusrite 2 i4，舒尔SM 57通过Focusrite 2 i4，变焦H2，变焦H4，谷歌Nexus 4，苹果iPhone和索尼摄像机（vx 2000）。报告与攻击释放和存在的任何动态处理的阈值相关的参数，并且探测设备的任何非线性行为，例如削波，如果识别出任何非线性行为，则通过提取将输入电平与输出电平相关的增益曲线来对其进行参数化。
大多数器件都有某种形式的动态增益控制，以防止信号削波，但实现方式明显不同。一些设备有许多选项和设置，用于不同的情况，表明没有一种特定的方法适用于所有情况。被测系统的攻击和释放时间分别为5 ~ 17 ms和30 ~ 400 ms。一些设备也可能展示出非线性增益曲线，没有攻击或释放，但试图通过使用1.4和10之间的压缩比来限制可听失真。而其他系统则没有保护，并且在出现过高的声级时将表现出硬削波。
This is a report detailing how a series of measurements were carried out to quantify the non-linear performance of a series of portable audio recorders. The performance of a series of common devices is quantified including the; Cannon 550D, Edirol r44, Neumann U87ai via Focusrite 2i4, Shure SM57 via Focusrite 2i4, Zoom H2, Zoom H4, Google Nexus 4, Apple Iphone and a Sony camcorder (vx2000). Parameters relating to attack release and thresholds of any dynamics processing present are reported, and the devices are probed for any non-linear behaviour such as clipping, if any non-linear behaviour is identified it is parameterised by extracting the gain curve which relates input level to output level.
Most devices have some form of dynamic gain control to prevent signal clipping, but the implementations clearly differ considerably. Some devices have many options and setting for different situations indicting that there is no one particular method suitable for all cases. The attack and release times of the measured systems range from 5 to 17 ms and 30 and 400 ms respectively. Some devices may also demonstrate a nonlinear gain curve with no attack or release but which try to limit audible distortion by using a compression ratio of between 1.4 and 10. While other systems have no protection and when presented with excessive sound levels will exhibit hard clipping.