Play with these formulas:
ASPD formulaDisplayed ASPD
ASPD = 200-(Delay*DelayDecrease)
* Delay = (250-AGI-(DEX/4))*(200-ASPD Base)/250
* DelayDecrease = 1-Speed Mod
Dual Wielding ASPD Base formulaASPD Base = 280-(1351/135000)*((200-ASPD Base Weapon1)*(ASPD Base Weapon1)+(200-ASPD Base Weapon2)*(ASPD Base Weapon2))
Note: For Dual ASPD Base of Sword, use 138 instead of 135.
Check this site for more informations about what ASPD Base's are about
http://irowiki.org/wiki/ASPDFor Speed Mod, it equals (100-ImprovementPercentages)/100. (Doppelganger Card gives 33%, Awake Pot gives 15%.)
I have kinda calculated the DD dual daggers case, your (Agi+(Dex/4)) needs to be 62.25 in order to just reach 190 ASPD.