MySQL beta at CHEARSdotinfo co uk

Lesson 9

In 錄/录 a voice in a 间 there is no escaping the 声学 效果(效应) of the 环境 The 声波 is contained by the 表面 of the 间 and size 形状 and proportions of
the 间 and the 吸收 and 反射 特征 of the 表面 测定(确定) the 声波 领域(野外) in the 间

With the 声筒(麦克风) close to my lips the 直 声波 主宰 The 声波 反射 from
the walls floor and ceiling is weaker because
it travels farther and some 声波 能量 is lost at each 反射 The greater the 声筒(麦克风) 距 the more the 间 效果(效应) 主宰

I will hold the 声筒(麦克风) at a 持续 距 from my lips so that the 直 声波 will be unchanged

By walking toward the plywood the 声波 反射 from it will 增 the closer I get

The 整体 效果(效应) can be simulated for easy 研究 by using a 延迟 设备 In the 跟随 例如 a voice 信号 is 合并 with the same 信号 延迟 one-half of a thousandth of a second or one-half 毫秒 with respect to the 直 声波

Voice 色 result any 时间 a 声波 组成 is 合并 with itself 延迟 a bit The plywood 反射体 provided such a 延迟 with a single 声筒(麦克风) A hard table top close to the 声筒(麦克风) can do the same thing

If the same 声波 撞击 two 声筒(麦克风) separated at a 距 and the outputs of the two are 合并 wild 频率 响应/反应 变动 will result At 频率 at which the two components are in 相位 the 信号 add giving a 6-dB 峰 At 频率 at which they are out of 相位 they cancel resulting in a 30- or 40-dB 谷 in 响应/反应 Down through the 可听 频谱 these 峰 and 谷 剧烈 change our 通常 uniform 响应/反应 and this is what changes the character of the 声波 This is commonly called a 梳状 滤器 because the 频率 响应/反应 峰 and 谷 look like a 梳状 when plotted