Angelina Jolie

Is an oscilloscope required for making a synthesizer?

I want to build this analog synthesizer kit. (See link below). However, the website says one has to have an oscilloscope. Is that true? If so, what frequency? Is it possible to use a computer as an oscilloscope? (I have a BA in Math and another in computer science, a first year physics course and a high school electronics course. However, I have only build a few small circuits and only have a digital multimeter and a breadboard.)

http://www.musicfromouterspace.com/index.php?MAINTAB=CATALOG&CATPARTNO=SLMSMARKII_COMBO2&VPW=1277&VPH=731