% ECE 1250 S12 Lecture 1
%
% PowerPoint presentation: Sound Overview
%
% The Matlab¨ desktop:
% 1) Current Folder (put code here and Matlab¨ will find it)
% 2) Workspace (shows what values are stored by Matlab¨ in named variables)
% 3) Command History (previous commands, use arrow keys, too)
% 4) Command Window (type commands into the glorified graphing calculator that is Matlab¨)

% Housekeeping:
% 1) Use Preferences in MATLAB menu to set print format to compact
% 2) Change current folder to Desktop so Matlab can find files
% 3) >> pwd   % print current directory
% 4) Use Set Path under File Menu to add desired folder to where Matlab¨ looks for files (remember to Save before you Close the Set Path window)

% Cool things Matlab¨ can do:
>> load handel   % load a snippet of Handel's "Messiah"
>> sound(y)      % play the snippet of "Messiah" stored in variable "y"
>> plot(y(1:200))  % Shows us what the sound waveform looks like
>> y = y(2000:4048)*0.3;  % extract a portion of the sound waveform
>> sound(y)        % "ah" sound
>> plot(abs(fft(y(2000:4048))))   % Shows the frequencies in the "ah" sound
% Our goal in the labs will be to analyze sounds and then create a sound effect.

% Matlab¨ works like a calculator, but everything is typed out:
>> sin(pi)     % pi is built-in constant.
% The answer should have been zero, but Matlab¨ is numerical and rounds off.  Be careful.
sqrt(-1)         % The square root of -1 is imaginary.  Matlab¨ is okay with that.

% Some things not in the early part of the book but Very useful:
% 1) Put a semicolon ; at the end of a command to suppress printout.  Very handy
%    huge arrays you don't want to see.
% 2) Use the >>diary on  and >>diary off  commands to create a file containing
%    a transcript of your Matlab¨ session, input and output.