Ok, maybe you just have to on your speaker louder. I had made a
test using a normal mp3 and mosquito mp3 at a sampling frequency of
44khz, normal human can hear 20hz to 20khz.
From normal discrete signal we had is sin(2*pi*f*t) t is realated
to the sampling frequency (fs) which is 1/fs = T, T/N =t.
N is the sampling rate.
From the analog signal, I can see that it is within human ear
range, therefore shouldn't be any problem. 
