Buffer Spectrum

Hi, yesterday I tried to make some audio visualization not by midi, but by frequency analysis. I used the spectrum of the Audio Input and made some parameters variations of a shape. Then, the problem is that the spectrum give so many values, and they are not stable at all, they change so fast that the shape looks like "nervous". Also if you download of the many tutorials of how to make a sound spectrum, or frequency analysis, you can see that the bars are never really still, i mean they continue to move also if you send the auido by line in. Thats cause the spectrum gives so many values and they change so fast.

Someone know how to fix that?

Thank you jaco