Interface: M-Audio M-Track (2-channels) USB interface
If I plug my headphones into the interface I hear the bass perfect, but I can only hear the app music through the laptop speaker...so I can have one ear off the headphones and do it like that, but that's a bit annoying. When I tried your fix and plugged the headphones into the laptop I hear everything through the headphones but the bass is delayed.
I'm thinking this is something with the app because there's no delay at all when I record in Garageband, so it's not a physical set up thing.
I've also done it just using the laptop mic without the USB interface, and plugged into an amp, and that's fine, the timing seems pretty good.