Audio K7 is not a common word (I guess)

[jmuheim]

...a little like when you had to find the beginning of a song on a audio K7.

I don't think that this is a common word in english. I had to google it to know what it is. Better call it "audio cassette".

[qtnc]

Oh, sorry. I believed that it was a quite common abbreviation. I have changed it on the original tutorial book now.