# Why does the standard waveform from audio out get distorted when I reduce the amplitude?

In my attempt to generate a standard sine wave out of a sound card, I started using matlab which has a function soundsc for scaling the output

 t = 0:1/48000:10;
y = sin(1000*2*pi*t);
soundsc(y,48000,[a b]);


It's ok when my a and b are -1 and 1 respectively. When I try to make them even -0.9 and 0.9 respectively, the standard sine wave of 1Khz gets distorted, why?

Are our sound cards not able to handle standard sounds?

soundsc(y,48000,[-2 2]);