Help in audio visual performance

Hi all, I have read the tutorial made by Masato Tsutsui talking about Audio Visual performance (http://audiovisualacademy.com/avin/en/software/maxmspjitter-masato-tsutsui-audio-part-2/).
The tutorial is quite difficult for me as I am just a beginner of Max, and I just followed the steps but not understanding all of the steps he made.

I find problems in controlling the "graphic" generated by the sound input. As the graphic travels, the x-axis is working well but the graphic is not working perfectly on the y-axis, as it exceeds the range of the y-axis (ie. the wave jumps across the boundaries of the upper and the lower limit).

I try to solve the problem of controlling the movement of y-axis by decreasing the size of the graphic, but the result is not desirable. As the x-axis is also decreased, then the wave could only travel a very small distance on x-axis. Also, the wave becomes not too visible when the size of wave is decreased.

I would like to know is there any method to deal with controlling the graphic...? regarding controlling the movement in y-axis, my patch is attached for the reference. Sorry for my poor english proficiency and I am so worried about this as I am going to perform with this patch in a few weeks.