Can someone tell me wtp "dubstep" actually is?

Touhou Rock and Metal? Sec. Coming up.

[spoiler="幻想の結界" - 彩音 ～xi-on～]
[video=youtube;-dDussny3Rs]http://www.youtube.com/watch?v=-dDussny3Rs[/video][/spoiler]

[spoiler="フラワリングナイト" - 彩音 ～xi-on～]
[video=youtube;FXeJJqSB-BU]http://www.youtube.com/watch?v=FXeJJqSB-BU[/video][/spoiler]

[spoiler="Holy Butterfly" - CROW'SCLAW]
[video=youtube;r8tGh0_vXDM]http://www.youtube.com/watch?v=r8tGh0_vXDM[/video][/spoiler]

[spoiler="亡き王女の為のセプテット" - 高瀬]
[video=youtube;3Wm7QeIRbp8]http://www.youtube.com/watch?v=3Wm7QeIRbp8[/video][/spoiler]

[spoiler="Lunatic Phase" - ELECTRIC RED]
[video=youtube;RQvV2p_6-fo]http://www.youtube.com/watch?v=RQvV2p_6-fo[/video][/spoiler]

[spoiler="Master of Time with the Luna Dial" - Sonic Hispeed Omega]
[video=youtube;ZwqfkJV3Z4U]http://www.youtube.com/watch?v=ZwqfkJV3Z4U[/video][/spoiler]

[spoiler="Septette for the Dead Princess" - Sonic Hispeed Omega]
[video=youtube;w64mv78HgTM]http://www.youtube.com/watch?v=w64mv78HgTM[/video][/spoiler]

[spoiler="Cavalrymaid" - IRON ATTACK!]
[video=youtube;dKcaK8kw2PI]http://www.youtube.com/watch?v=dKcaK8kw2PI[/video][/spoiler]

Sec, getting more, I have to look in my media library to remember the songs I enjoyed.

EDIT: Too many metal songs I like, I only put one up though. Actually, I'll try getting some more from YT, but there's too many Metal songs I like.