 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