I’ve been working on this issue all week, hope in the right section. My tascam model 12 connects to my computer but cant get it working through Asio with daw controller. I am using adobe audition, I connect using Asio I cant get my mics recognized individually. Only channel I can use is 1 or 2 but every mic is used for both. I’m sure I started it off wrong during set up in some way or I set up my tascam to my hp incorrectly some how. Anything you need from me or help you can give will be great. Also, this if for my 4 mic podcast recording individually is key for me.
Welcome to the MRC community @dw43679!
Maybe @Mike can help you out with this as I think he owns a unit 
Hes the one that sent me here lol
Thanks for the screenshot @dw43679. It seems from there that you can select all the channels individually there from your recording selection menu.
If this isn’t working well for you then it may be worth to check the input on Audio Hardware and the Preferences menu. You can also have a look at Audio Channel Mapping which is also under Preferences for a list of all the channels on your TASCAM Model 12 desk that can be mapped.
If there’s still no luck take a look as ASIO4ALL which can solve many issues with inputs and especially multiple microphones.