How to save samples from audio files?

I have the following code for a digital signal processing problem with the file

[x,Fs] = audioread('speech_tait(2).m4a');
sound(x,Fs)
plot(x)
xlabel('Time')
ylabel('Audio Signal')
info = audioinfo('speech_tait(2).m4a');
t = 0:seconds(1/Fs):seconds(info.Duration);
t = t(1:end-2);
L = 1000; 
VoicedSpeech = x(L:0+ L-1);
UnvoicedSpeech = x(L:0 + L-1);

%subplot(2,1,1);
% x1 = linspace(0,7);
% y1 = VoicedSpeech;
% plot(x,y1)
% 
% subplot(2,1,2);
% y2 = UnvoicedSpeech;
% plot(x,y2)

I need to save 100 samples from the voiced segment (first spike) of the speech into a MATLAB vector called VoicedSpeech and save 300 samples from the unvoiced segment (second spike) of the speech into a MATLAB vector called UnvoicedSpeech, then use the subplot command to plot the two signals, VoicedSpeech and UnvoicedSpeech, on a single figure.

The commented part always gives me an error about having the wrong vector length.

Answer 1

[Walter Roberson]

L = 1000; 
VoicedSpeech = x(L:0+ L-1);

When L is 1000, then the : expression is 1000:0+1000-1 which is 1000:999 which is going to be the empty vector.

You need to analyze the signal in x to figure out where a long-enough voiced segment starts, and extract 1000 from there, and where a long-enough unvoiced segments starts and extract 300 from there.

vp =  appropriate value for where the voiced segment starts
VoicedSpeech = x(vp:vp+L-1);