MySQL beta at CHEARSdotinfo co uk

Lesson 2

声波 级 a 物理 quantity 测量 with 乐器

响度 a 心理物理学 感（觉） 感知（认为） by the 人类 耳 / 脑 mechanism

Decibel one-tenth of a 贝尔 which is the 算法 of the 比 of any two power-like quantities

算法 common 对数 to base 10 of a 数 is the exponent of 10 that yields that 数

When these 音 are reproduced on a 扬声器 you will notice that changes in head 位置 change the 响度 of the 声波 due to 间 效果 For this reason keep your head in one 位置 during each test Of course if you are 聆 on 耳机 间 声学 have no 效果（效应）

A change of 10 dB is often considered to be a 加倍 of 响度 or cutting 响度 in half

A 10-dB change in 级 is less noticeable at
 100 赫兹（he zi） but very prominent at 1000 赫兹（he zi） The 最小 可辨别 级 change depends both on the 频率 and the 级 of the 声波