"the size of three tennis courts" and described by Spring as "a machine on the move". A vast electrical grid, composed of truss sections, chain motors, electrical cables and the control devices that linked electronically or mechanically with the performances happening, was hung from above; four video screens formed the backdrop of the stage. Other material included a mechanical bull and equipment designed for aerial movements. The sets were built in sections made by three companies. A permanent crew of one hundred persons, ranging from lighting, sound and carpenters to dancers, wardrobe and make-up, was hired. Monitor mixing was handled by four monitor engineers, with two of them for Madonna's monitors. Blake Suib, one of the engineers, commented that Madonna was a perfectionist, as she could tell when a sound coming from the speakers sounded bad or good during rehearsals. By suggestion of music director Pat Leonard, they tried out using 14 kHz of sound frequency in their live speakers, which was unusual to use at the time. They also came up with the idea of using isolated amplifiers to pick up the individual sound of each instruments. Suib commented that "the creative process of coming up with new ideas, implementing them, and then soberly evaluating their results was time-consuming but worth it". Dave Kob, FOH engineer for the tour, explained: "The show is extremely technical, extremely fast-paced, and the variety of music is amazing. [...] It goes from screaming heavy metal to techno dance, to Country and Western; there's even a flamenco hootenanny where everyone comes down front, beats on logs and plays acoustic guitars and pennywhistles. Then it goes back to 'Holiday' which is an old dance number. It keeps you steppin'. Madonna sings everything live. She's been that way from the beginning of her career, even with all the athletic dancing. She's a hard worker and she expects everybody else to work as hard or harder. I respect that. Designer Jean Paul Gaultier was signed up to create the costumes for the tour; his designs had a fusion of punk and Scottish fashions, geisha, cowboy and Spanish themes. These included torn shirts and zippered black pants, a nod to Madonna's early days; black wigs and white makeup which referenced the geisha aesthetic used on "Nothing Really Matters" (1999); leather chaps over jeans like the ones she wore on her "Don't Tell Me" music video, and a "hybrid"