Sound effects Our project Background & techniques Applications Methodology Results Conclusion

artificially created or enhanced sounds› Delay › Multiple Echo › All pass Reverberation › A Natural Sounding Reverberation › Flanging › Equalizer

plays audio after the delay time from several milliseconds to several

seconds Analog delay Digital delay is used by electric guitarists

Reflection of sound infinite number of echoes in music may produce unpleasant

effect

result of the many reflections of a sound

sound source stops but the reflections continue

number of systems developed to simulate reverberation

simple DSPs use multiple feedback delay circuits

Impulse response of a room

"whooshing" sound created by mixing a signal with a

slightly delayed copy of itself considered a particular type of phasing

effect

allows the user to magnify or dampen any frequencies

Many equalizers change up to 20 different frequency bands

various effects on pre-recorded sound› Delay › Multiple Echo › All pass Reverberation › A Natural Sounding Reverberation

audio file manipulated in visual dsp++

Output produced on sound card

musicians have been using different techniques

Some of these were found by accident effects have not changed much in the

past few years from analog signal processing towards

digital signal processing very precise and easily reproduced

effects

In movies and theaters To make voice listened better in

different environments in a recording studio gives you greater choice of sounds better control over different devices

used For improving the quality of music

Delay:

Open a file in read mode… int R=5000; for(i=0;i<R;i++)

y[i] = x[i];

for(j=R;j<xlen;j++) y[j]= x[j]+x[j-R];

Multiple Echo:

H(Z) =  Z-R / (1 - alpha * ( Z-R))

int R=5000; int aa =0.5; for(i=0;i<R;i++) y[i] = x[i];

for(j=R;j<xlen;j++)

y[j]= x[j]+(aa*x[j-R]);

All pass Reverberation:

A Natural Sounding Reverberation: Schroeder's Reverberator

input

output

Different sort of effects and filtering techniques

Sound effects are done digitally allowing for a wider variety of manipulation

By the application of DSP, sound quality can be improved