I heard or read an interview with Iggy Pop once, and in it he said he would go around to different factories and shops in the Detroit area to listen to the sounds the machinery and equipment made, and then use those sounds to influence his music.
Nine Inch Nails helped popularize industrial rock by introducing conentional song structures to it(I like Reznor,just clarifying)-I wouldn't call them 'typical' examples of industrial music.Industrial rock can be traced back to early pioneers electro pop/experimental Kraftwerk to aaggressive noise like Throbbing Gristle and avant garde sounds like Cabaret Voltaire.
Listen to Closer by Nine Inch Nails; it's a good example of industrial. It has a lot of heavy yet subtle sounds.
No it's not the fact that bands use equipment or machinery to make the music. It means that the beats and sounds are heavier. Listen to Nine Inch Nails they seem to have a more Industrial Metal sound.
