## The tremolo effect (Underwater), the vibrato effect and the Echo/reverberation effects can be applied to group of frequencies just as it can to a single frequency.

### engineering

##### Description

(Q3) The tremolo effect (Underwater), the vibrato effect and the Echo/reverberation effects can be applied to group of frequencies just as it can to a single frequency. On the piano, the F-Major chord is made up of the notes F, A, and C which correspond to the frequencies 349.228 Hz, 436.682 Hz, and 523.271 Hz respectively. Create three sine waves at these frequencies and add them together to synthesize the chord. Use a sample frequency of 44100 Hz and normalize the amplitude of the result to 1. Use the MATLAB® function Sound to listen to your chord. Create a cosine wave at 5 Hz with amplitude 0.3.

a) Using your cosine function to modulate your F-major Chord, create a tremolo effect. Plot the frequency content of the original chord with tremolo effect using FFT. Use the sound function to play first the original F-major Chord sound, afterwards Play the tremolo effected F-Major chord after a 4 second pause.

b) Using your cosine function to modulate your F-major Chord, create a vibrato effect. Plot the frequency content of the original chord with vibrato effect using FFT. Use the sound function to play first the original F-major Chord sound, afterwards Play the Vibrato effected F-Major chord after a 4 second pause.

c) Using an attenuation factor of 0.75, create a cascaded echo or reverberation effect of the F-major chord allowing the sound to be reverberated 4 times with the shortest delay time about a tenth of the longest delay time, making sure that all 4 four delays are mutually primed not to produce artificial resonances. Plot the frequency content of the original chord the final reverberation using FFT. Use the sound function to play first the original F-major Chord sound, afterwards Play the Echo after a 4 second pause.