A Speedmod is a modifier in several music games like In The Groove, Beatmania, Dance Dance Revolution or O2Jam. A lot of Speedmods look like "x3" or "x 2.5".
When you play a song the notes of the songs will be displayed according to the BPM of the song (Beats per minute).
After you used a Speedmod the scrolling speed of the displayed notes will increase or decrease, but it won't change the BPM of the song.
Many players are using Speedmods to increase their playing skill and timing.
Song BPM = 150
Scrolling Speed = 150
Speedmod 0.5x = 150 BPM, Scrolling Speed = 75
Speedmod 2x = 150 BPM, Scrolling Speed = 300