PCM DECODING : effect of different sample frequency

I Used “resample” command to see the effect of changing the frequency of

9-bit quantized signal for the following casses ( fs=44100, fs=2000 and fs=300)

on both the size of the data and the sound quality while decreasing the sample frequency

I can't hear the sound for fs = 300 because it gives me Error using sound (line 76) Device Error: Invalid sample rate please if you know how solve this problem help me , Thank you

another thing , I don't notice a very big difference between fs=44100 and fs=2000 why ?!

fs=44100;     
ts=1/fs;      
t=0:ts:4-ts;  

x1 = audiorecorder(fs, 16, 1); 
disp('Start speaking.') 
recordblocking(x1, 4);
disp('End of Recording.');

m=getaudiodata(x1);        
m1=resample(m,2000 , 44100);  
m2=resample(m,300 ,  44100);

n9=9;                
L9=2.^n9;            

delta2=2.00001.*max(abs(m))/L9;         
delta4=2.00001.*max(abs(m1))/L9;        
delta8=2.00001.*max(abs(m2))/L9;        

mqfO= delta2.*floor(m/delta2)  + delta2/2;      
mqf1= delta4.*floor(m1/delta4) + delta4/2;      
mqf2= delta8.*floor(m2/delta8) + delta8/2;      

sound(mqfO,fs);    
pause(5)
sound(mqf1,2000);     
pause(5)
sound(mqf2,300);