There is a program out there for dual-login called AuMulti developed by fr0zeN,
but it requires you to pay for the paid version of the program in order to use the dual-login function =(.
But don't worry, let me share a method i found that we can use to dual-login auditionsea but it only works on windows vista (i don't know why, i think its uac).
Basically you have to copy your AuditionSEA folder (~2.19gb).
If you want to open 5 accounts, you have to copy and paste 5 of such folders to any directory in your computer.
In my case, i paste it into "C:\" and rename the folder to Audition2, Audition3 and so on.
The default folder will look like this:
In the other folders, just rename the patcher which you use to launch the game to anything else.
The uac shield will disappear at the bottom right of the icon and will look like this
I renamed mine from Patcher._xe to wwgrhj
Just put the shortcut to the respective patchers in the desktop.
First, launch the patcher with the uac shield.
A uac msg will appear, prompting Allow or Cancel right? Allow and log in an account with that patcher.
Now launch another patcher which you have renamed (w/o uac shield), no uac msg should appear, just click 'Game Start' and a 2nd Audition will appear!
And there, you can log in a 2nd acc now.
For subsequent accounts, launch the other renamed patchers.
End result will look something like this:
If you have a stable fps of 60 in window mode, you should be able to open up to 3-4 accs before you start to lag bad (depending on your computer).
The in-game fps will decrease naturally as you open up more accounts.
You can use this to tag exp if you have the time and money but i seldom tag x.X .