%read the audio file x samples, output Fs
[x,Fs]= audioread('Guitar_notes.wav');
%take the fourier transform
xdft = fft(x);
xdft = xdft(1:length(x)/2+1);
% create a frequency vector
freq = 0:Fs/length(x):Fs/2;
%locs is now in frequency
[pks,locs] = findpeaks(20*log10(abs(xdft)));
%finds the peaks within the range of the fundamental frequency of the notes
indesiredrange = locs > 150 & locs < 500;
%gets the subsets within range
pks_subset = pks(indesiredrange);
locs_subset = locs(indesiredrange);
figure(1)
semilogx(freq,20*log10(abs(xdft)))
hold on
plot(freq(locs_subset), pks_subset, 'or')
hold off
xlabel('f(Hz)');
title('FFT of signal')

[pks,locs] = findpeaks(20*log10(abs(xdft)), freq);