reverberator

Add reverberation to audio signal

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描述

Thereverberator系统对象™ adds reverberation to mono or stereo audio signals.

To add reverberation to your input:

创建reverberatorobject and set its properties.
Call the object with arguments, as if it were a function.

To learn more about how System objects work, seeWhat Are System Objects?

Creation

Syntax

混响= Reverberator

Reverb = Reverberator（Name,Value)

描述

混响= Reverberatorcreates a System object,reverb，这将人工混响添加到音频信号中。

Reverb = Reverberator（Name,Value)sets each propertyNameto the specifiedValue。Unspecified properties have default values.

例子：Reverb = Reverberator（'PreDelay',0.5,'WetDryMix',1)creates a System object,reverb, with a 0.5 second pre-delay and a wet-to-dry mix ratio of one.

Properties

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Unless otherwise indicated, properties are不可否认，这意味着您在调用对象后不能更改其值。呼叫时锁定对象，然后releasefunction unlocks them.

If a property istunable, you can change its value at any time.

For more information on changing property values, seeSystem Design in MATLAB Using System Objects。

`PreDelay`—Pre-delay for reverberation (s)
`0`(default) |real positive scalar

Pre-delay for reverberation in seconds, specified as a real scalar in the range [0, 1].

Pre-delay for reverberationis the time between hearing direct sound and the first early reflection. The value ofPreDelayis proportional to the size of the room being modeled.

Tunable:Yes

Data Types:single|双倍的

`HighCutFrequency`—低通滤波器截止（Hz）
`20000`(default) |real positive scalar

Lowpass filter cutoff in Hz, specified as a real positive scalar in the range 0 to $(\frac{S a m p l e R a t e}{2})$ 。

Lowpass filter cutoffis the –3 dB cutoff frequency for the single-pole lowpass filter at the front of the reverberator structure. It prevents the application of reverberation to high-frequency components of the input.

Tunable:Yes

Data Types:single|双倍的

`Diffusion`—混响尾
`0.5`(default) |real scalar

混响尾部的密度，在[0，1]中指定为真实的正标量。

Diffusion与混响尾部密度建立的速率成正比。增加Diffusionpushes the reflections closer together, thickening the sound. ReducingDiffusion创建更多离散的回声。

Tunable:Yes

Data Types:single|双倍的

`decayFactor`—Decay factor of reverb tail
`0.5`(default) |real scalar

混响尾部的衰减因子，在[0，1]中指定为真实的正标量。

decayFactor与反射耗尽能量所需的时间成正比。要建模一个大房间，请使用长长的尾巴（低衰减因子）。要建模一个小房间，请使用短尾巴（高衰减因子）。

Tunable:Yes

Data Types:single|双倍的

`HighFrequencyDamping`—High-frequency damping
`0.0005`(default) |real scalar

High-frequency damping, specified as a real positive scalar in the range [0, 1].

HighFrequencyDamping与混响输出中高频的衰减成正比。环境HighFrequencyDampingto a large value makes high-frequency reflections decay faster than low-frequency reflections.

Tunable:Yes

Data Types:single|双倍的

`WetDryMix`—Wet-dry mix
`0.3`(default) |real scalar

湿干的混合物，在[0，1]中指定为真实的正标量。

Wet-dry mixis the ratio of wet (reverberated) to dry (original) signal that yourreverberator系统对象outputs.

Tunable:Yes

Data Types:single|双倍的

`SampleRate`—Input sample rate (Hz)
`44100`(default) |positive scalar

Input sample rate in Hz, specified as a positive scalar.

Tunable:Yes

Data Types:single|双倍的

Usage

Syntax

audioOut = reverb(audioIn)

描述

example

audioOut= reverb(Audioin)adds reverberation to the input signal,Audioin, and returns the mixed signal,audioOut。The type of reverberation is specified by the algorithm and properties of the reverberator System object,reverb。

Input Arguments

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`Audioin`—Audio input to reverberator
column vector|N-by-2矩阵

Audio input to the reverberator, specified as a column vector or two-column matrix. The columns of the matrix are treated as independent audio channels.

Data Types:single|双倍的

Output Arguments

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`audioOut`— Audio output from reverberator
N-by-2矩阵

Audio output from the reverberator, returned as a two-column matrix.

Data Types:single|双倍的

Object Functions

To use an object function, specify the System object as the first input argument. For example, to release system resources of a System object namedobj，使用此语法：

release(obj)

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Specific to reverberator

`CreateAudiopluginClass`	Create audio plugin class that implements functionality of系统对象
`parametertuner`	Tune object parameters while streaming

Midi

`configureMIDI`	Configure MIDI connections between audio object and MIDI controller
`disconnectMIDI`	Disconnect MIDI controls from audio object
`getMIDIConnections`	获取音频对象的MIDI连接

Common to All System Objects

`clone`	创建重复系统对象
`isLocked`	确定是否系统对象正在使用
`release`	Release resources and allow changes to系统对象property values and input characteristics
`重置`	重置内部状态系统对象
`步`	Run系统对象algorithm

例子

collapse all

Add Reverberation to Audio Signal

Open Live Script

Use thereverberator系统对象™ to add artificial reverberation to an audio signal read from a file.

创建dsp。AudioFileReaderandaudioDeviceWriter系统对象s. Use the sample rate of the reader as the sample rate of the writer.

fileReader = dsp.AudioFileReader('Funkydrums-44p1-stereo-25secs.mp3','SamplesPerFrame'，1024）;DeviceWriter = AudioDeviceWriter（'SampleRate'，fileReader.mamplater）;

Play 10 seconds of the audio signal through your device.

ticwhiletoc <10 audio = filereader（）;DeviceWriter（音频）;endrelease(fileReader)

Construct areverberator系统对象with default settings.

混响= Reverberator

混响= Reverberatorwith properties: PreDelay: 0 HighCutFrequency: 20000 Diffusion: 0.5000 DecayFactor: 0.5000 HighFrequencyDamping: 5.0000e-04 WetDryMix: 0.3000 SampleRate: 44100

Construct a time scope to visualize the original audio signal and the audio signal with added artificial reverberation.

scope = timescope(。。。'SampleRate',fileReader.SampleRate,。。。'TimeSpanOverrunAction','Scroll',。。。'TimeSpanSource','property',。。。'TimeSpan'，3，。。。“ BufferLength”,3*fileReader.SampleRate*2,。。。'YLimits',[-1,1],。。。“ showgrid',true,。。。'ShowLegend',true,。。。'标题','Audio with Reverberation vs. Original');

Play the audio signal with artificial reverberation. Visualize the audio with reverberation and the original audio.

while~isDone(fileReader) audio = fileReader(); audioWithReverb = reverb(audio); deviceWriter(audioWithReverb); scope([audioWithReverb(:,1),audio(:,1)])end释放（filereader）版本（设备沃特）版本（范围）

调节混响参数

Open Live Script

Create adsp。AudioFileReaderto read in audio frame-by-frame. Create anaudioDeviceWriterto write audio to your sound card. Create areverberator处理音频数据。

frameLength = 1024; fileReader = dsp.AudioFileReader('Rockdrums-44p1-stereo-11secs.mp3',。。。'SamplesPerFrame',frameLength,'PlayCount',2); deviceWriter = audioDeviceWriter('SampleRate'，fileReader.mamplater）;Reverb = Reverberator（'SampleRate'，fileReader.mamplater）;

Callparametertunerto open a UI to tune parameters of theoctaveFilterwhile streaming.

parametertuner(reverb)

在音频流循环中：

在文件中阅读音频框架。
Apply reverberation.
Write the frame of audio to your audio device for listening.

While streaming, tune parameters of the reverberator and listen to the effect.

while~isDone(fileReader) audioIn = fileReader(); audioOut = reverb(audioIn); deviceWriter(audioOut); drawnow限制% required to update parameterend

作为最佳实践，请释放一旦完成的对象。

release(deviceWriter) release(fileReader) release(reverb)

提示

TheCreateAudiopluginClassandconfigureMIDI功能映射可调属性compressorto user-facing parameters:

Property	Range	Mapping	Unit
`PreDelay`	[0, 1]	linear	s
`HighCutFrequency`	[20, 20000]	日志	Hz
`Diffusion`	[0, 1]	linear	没有任何
`decayFactor`	[0, 1]	linear	没有任何
`HighFrequencyDamping`	[0, 1]	linear	没有任何
`WetDryMix`	[0, 1]	linear	没有任何

Algorithms

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添加混响的算法遵循板级混响拓扑[1]and is based on a 29,761 Hz sample rate.

The algorithm has five stages.

以下算法的描述是用于立体声输入的。单声道输入是简化的情况。

Stereo-to-Mono

A stereo signal is converted to a mono signal: $x [n] = 0.5 \times (x_{R} [n] + x_{L} [n])$ 。

Preconditioning

A delay followed by a lowpass filter preconditions the mono signal.

The pre-delay output is determined as $x_{p} [n] = x [n - k]$ ,那里的PreDelayproperty determines the value ofk。
The signal is fed through a single-pole lowpass filter with transfer function

$L P (z) = \frac{1 - α}{1 - α z^{- 1}},$

where

$α = \exp (- 2 π \times \frac{f_{c}}{f_{s}}) 。$
- f_cis the cutoff frequency specified by theHighCutFrequency财产。
- f_sis the sampling frequency specified by theSampleRate财产。

解相关

The signal is decorrelated by passing through a series of four allpass filters.

Allpass过滤器是形式的

$A P (z) = \frac{β + z^{- k}}{1 + β z^{- k}},$

whereβis the coefficient specified by theDiffusionproperty andk是延迟如下：

ForAP₁,k= 142.
ForAP₂,k= 107.
ForAP₃,k= 379。
ForAP₄,k= 277.

Tank

The signal is fed into the tank, where it circulates to simulate the decay of a reverberation tail.

The following description tracks the signal as it progresses through the top of the tank. The signal progression through the bottom of the tank follows the same pattern, with different delay specifications.

The new signal enters the top of the tank and is added to the circulated signal from the bottom of the tank.
The signal passes through a modulated allpass filter:

$M o d u l a t e d A P_{1} (z) = \frac{- β + z^{- k}}{1 - β z^{- k}}$
- βis the coefficient specified by theDiffusion财产。
- kis the variable delay specified by a 1 Hz sinusoid withamplitude = (8/29761)*SampleRate。To account for fractional delay resulting from the modulatingk，使用Allpass插值[2]。
The signal is delayed again, and then passes through a lowpass filter:

$L P_{2} (z) = \frac{1 - φ}{1 - φ z^{- 1}}$
- φis the coefficient specified by theHighFrequencyDamping财产。
该信号乘以指定的增益decayFactor财产。然后，信号通过Allpass过滤器：

$A P_{5} (z) = \frac{β + z^{- k}}{1 + β z^{- k}} 。$
- βis the coefficient specified by theDiffusion财产。
- k被设定为1800for the top of the tank and2656for the bottom of the tank.
The signal is delayed again and then circulated to the bottom half of the tank for the next iteration.

A similar pattern is executed in parallel for the bottom half of the tank. The output of the tank is calculated as the signed sum of delay lines picked off at various points from the tank. The summed output is multiplied by0.6。

Wet/Dry Mix

The wet (processed) signal is then added to the dry (original) signal:

$y_{R} [n] = (1 - κ) x_{R} [n] + κ x_{3 R} [n],$

$y_{L} [n] = (1 - κ) x_{L} [n] + κ x_{3 L} [n],$

在哪里WetDryMixproperty determinesκ。

参考

[1]Dattorro, Jon. "Effect Design, Part 1: Reverberator and Other Filters."Journal of the Audio Engineering Society。卷。45，第9期，1997年，第660-684页。

[2] Dattorro, Jon. "Effect Design, Part 2: Delay-Line Modulation and Chorus."Journal of the Audio Engineering Society。卷。45, Issue 10, 1997, pp. 764–788.

Extended Capabilities

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用法注释和限制：

System Objects in MATLAB Code Generation（MATLAB编码器）

Audio Toolbox Documentation

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reverberator

描述

Creation

Syntax

描述

Properties

PreDelay—Pre-delay for reverberation (s)0(default) |real positive scalar

HighCutFrequency—低通滤波器截止（Hz）20000(default) |real positive scalar

Diffusion—混响尾0.5(default) |real scalar

decayFactor—Decay factor of reverb tail0.5(default) |real scalar

HighFrequencyDamping—High-frequency damping0.0005(default) |real scalar

WetDryMix—Wet-dry mix0.3(default) |real scalar

SampleRate—Input sample rate (Hz)44100(default) |positive scalar

Usage

Syntax

描述

Input Arguments

Audioin—Audio input to reverberatorcolumn vector|N-by-2矩阵

Output Arguments

audioOut— Audio output from reverberatorN-by-2矩阵

Object Functions

Specific to reverberator

Midi

Common to All System Objects

例子

Add Reverberation to Audio Signal

调节混响参数

提示

Algorithms

Stereo-to-Mono

Preconditioning

解相关

Tank

Wet/Dry Mix

参考

Extended Capabilities

C/C ++代码生成生成C和c++代码使用MATLAB®编码器™。

See Also

Audio Toolbox Documentation

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Try MATLAB, Simulink, and Other Products

`PreDelay`—Pre-delay for reverberation (s)
`0`(default) |real positive scalar

`HighCutFrequency`—低通滤波器截止（Hz）
`20000`(default) |real positive scalar

`Diffusion`—混响尾
`0.5`(default) |real scalar

`decayFactor`—Decay factor of reverb tail
`0.5`(default) |real scalar

`HighFrequencyDamping`—High-frequency damping
`0.0005`(default) |real scalar

`WetDryMix`—Wet-dry mix
`0.3`(default) |real scalar

`SampleRate`—Input sample rate (Hz)
`44100`(default) |positive scalar

`Audioin`—Audio input to reverberator
column vector|N-by-2矩阵

`audioOut`— Audio output from reverberator
N-by-2矩阵

C/C ++代码生成
生成C和c++代码使用MATLAB®编码器™。