HW1.1 Phil Cannon ECE301Fall2008mboutin - Rhea

Sound Files

• a. Hail Purdue! at normal speed.
• b. Hail Purdue! twice as fast.
• c. Hail Purdue! twice the frequency.

Matlab Code

%Phil Cannon 
%pjcannon@purdue.edu
%ECE301 HW1_1

%This file takes roughly 30 seconds to compile completely and will play
%three different versions of 'Hail Purdue'.  Note: When the wave files are
%created MatLab produces a warning, but it doesn't seem to do anything.

delta=0.00005;

%Declare notes and note lengths
%Taken from:
%http://it4musos.com/audio_workshop/guitar%20note%20frequencies.jpg
Eflat=311; E=329; F=349; Gflat=370; G=392;
Aflat=415; A=440; Bflat=466; B=494; C=523; Dflat=554;

E=.125;
Q=.25;
H=.5;
HQ=H+Q;
DotQ=Q+(.5*Q);

%Array of notes for 'Hail Purdue!'
%Taken from: 
%http://www.purdue.edu/bands/media/Sounds/aamb/Hail%20Purdue%20Piano%20Sheet.pdf
Notes = [Eflat, F, G, Aflat, Bflat, C, C, Dflat, Dflat, Dflat, Aflat, Bflat, B, C];
NLength = [HQ, Q, Q, DotQ, E, Q, Q, Q, E, E, Q, E, E, HQ];

%Part A.  Compiles 'Hail Purdue'.
c1=1;
for counter=1:(length(Notes))
    
    t=0:delta:NLength(counter);
    d=sin(2*pi*t*Notes(counter));
    
    c2=1;
    while c2<length(d)
        HailPurdue(c1)=d(c2);
        c1=c1+1;
        c2=c2+1;
    end
end
fprintf('Part 1 compiled...')

%Part B.  Compiles 'Hail Purdue', but twice as fast.
c1=1;
for counter2=1:(length(Notes))
    
    t2=0:delta:.5*NLength(counter2);
    d2=sin(2*pi*t2*Notes(counter2));
    
    c2=1;
    while c2<length(d2)
        HailPurduex2(c1)=d2(c2);
        c1=c1+1;
        c2=c2+1;
    end
end
fprintf('\nPart 2 compiled...')

%Part B.  Compiles 'Hail Purdue', but twice the pitch.
c1=1;
for counter3=1:(length(Notes))
    
    t3=0:delta:NLength(counter3);
    d3=sin(2*2*pi*t3*Notes(counter3));
    
    c2=1;
    while c2<length(d3)
        HailPurdueTrans(c1)=d3(c2);
        c1=c1+1;
        c2=c2+1;
    end
end
fprintf('\nPart 3 compiled...')
fprintf('Boiler up!\n')

sound(HailPurdue,1/delta);
sound(HailPurduex2,1/delta);
sound(HailPurdueTrans,1/delta);

wavwrite(HailPurdue, 20100, 'hw1_1a.wav');
wavwrite(HailPurduex2, 20100, 'hw1_1b.wav');
wavwrite(HailPurdueTrans, 20100, 'hw1_1c.wav');

Results

This problem took some time, but it was nice learning how to make and play Hail Purdue in Matlab. The only thing that bothered me was a warning produced in Matlab when using wavwrite, however it didn't seem to be doing anything noticeable.