PRESONUS Central Station Plus Owner's Manual page 25

Owner's Manual
3.3.2 85 dB SPL Standard Reference 85 dB SPL 标准参考
This method of speaker calibration references a specific "standard" meter
reading to a certain acoustic level. This is the most technical, least subjective
method and is good for studios where a specific type of audio is produced or
where an industry-standard audio level exists (such as for film or broadcast).
One of the most common calibration standards (and the one presented here)
is -20 dBFS referenced to 85 dB SPL.
NOTE: dBFS means "decibels full scale" and is associated with decibel
amplitude levels in digital systems where there is a finite maximum available
level (such as in standard PCM encoding). The maximum level possible is
referred to as "0 dBFS." In digital systems with analog outputs (such as digital
interfaces), the analog-to-digital
and digital-to-analog converters (ADCs and DACs) are referenced so that 0 dBFS
equals a certain amount of analog voltage. (For example, a 0 dBFS tone
playing at unity gain from a FireBox measures +18 dBu, while a 0 dBFS
from a FireStudio Projectat unity gain measures +10 dBu.) It is important to
know your digital devices'0 dBFS referenceto preventclipping and to aid in
proper calibration.
这种扬声器校准方法是将一个特定的 "标准" 仪表读数与某个声级相参照。
这是技术性最强、主观性最弱的方法，适合于制作特定类型音频的演播室
或存在行业标准音频水平的地方（如电影或广播）。最常见的校准标准之
一（以及这里介绍的标准）是-20 dBFS，参考85 dB SPL。
注意：dBFS的意思是 "decibels full scale"，与数字系统中的分贝振幅水平
有关，其中有一个有限的最大可用水平（如标准PCM编码）。可能的最大
电平被称为 "0dBFS"。在具有模拟输出的数字系统中（如数字接口），模
数转换器和数模转换器（ADC和DAC）的基准是0dBFS 等于一定量的模拟
电压。(例如，FireBox 在统一增益下播放的0 dBFS音调测量为+18 dBu，
而FireStudio 项目在统一增益下播放的 0 dBFS 测量为+10 dBu)。了解你的
数字设备的0dBFS 参考值是很重要的，可以防止削波并帮助你正确的校准。
1. "Zero" the Speaker, Main, Cue, and Phones
levels by turning them fully counterclockwise.
2. Select the TRS1 Main Source and Speaker Output A.
3. Turnyourprimarymonitoringsystem's(connectedtoSpeaker
Output A) input level to its lowestsetting. Consult your monitor
system's user manuals or the manufacturer's Web site for
more information about adjusting the input or amplification
level.
4. Remove all effects processors (EQs, compressors, reverbs, etc.)
from the signalpathandplay500Hzto2.5kHz,bandwidth-limited
pinknoiseat -20 dBFS through your primary audio source outputs.
If you are calibrating a subwoofer, use 40 Hz to 80 Hz,
bandwidth-limited pink noise.
Youshould not hear the test tone. If you do, turn down
the speaker volume and repeat Step 1.
Calibration
Calibrating Speaker Levels 3.3
3
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