%---------------------------------------------------------------%
%------ 2) Plotting a few seconds of an audio signal  ----------%
%---------------------------------------------------------------%

[y,fs,NBITS] = wavread('wavefile.wav',[1000,751000]);
y = y(:,1);                             %converting waveform to mono
sound(y,fs);
magPlot(y,fs,'Frequency Spectrum');
wavwrite(y,fs,'NatePaternoster-Lab7-2.wav');

%---------------------------------------------------------------%
%------ 3) Plotting a few seconds of an audio signal  ----------%
%---------------------------------------------------------------%

% a. Using summation of sums of input x and impulse response h

x = [0, 0, 0, 1];           % x and h are vectors
h = [1, 1, 1, 1];
y = convolve(x,h);
z = conv(x,h);

% b. Using convolution theorem and FFT

x1 = [0, 0, 0, 1];           % x1 and h1 are vectors
h1 = [1, 1, 1, 1];
y1 = convolve2(x1,h1);
z1 = conv(x1,h1);

% c. Comparing the two methods of convolution

[input,fs] = wavread('snare1.wav');
[impulse,fs2] = wavread('room_impulse.wav');
input = input';
impulse = impulse';

tic;
output_a = convolve(input,impulse);
toc;

tic;
output_b = convolve2(input,impulse);
toc;

soundsc(output_b,fs);
output_b = 0.04*output_b;
wavwrite(output_b,fs,'NatePaternoster-Lab7-3');