Using iphone musical apps on my mac?

You could try and connect the headphone out of the iPhone to the line input of the macbook and then in GarageBand create a basic (audio) track. Then click on the Input settings, and set the input to the stereo line in; problem with that will be setting the iPhone’s output levels such that you won’t overload the input (which is tricky because the iPhone’s output is amplified).

A better solution if you’re trying to do a quality recording is to invest in one of those iPod dock devices, such as the Apple iPhone dock. If it has a line out jack on the dock (the iPod docks did, not sure if the iPhone ones do too), then you take the line out from the dock, and connect to the MacBook the same way as described above. That way, you’re going line out of the iPhone (not amplified) to line in on the MacBook, eliminating the chance of distortion. No level setting from the iPhone, except the output level from inside the NLog Synth app’s volume level.

An even “more” pro solution is to get a dedicated audio interface (USB audio interface, for example), and then run the iPhone through that rather than direct line-in, but I’m not sure how “clean” a signal you’re trying to do. If it were studio quality recording you’re after, I would suggest that approach.

worked perfectly. thanks! i’m not really looking for high quality recordings at the moment just trying to create and have fun with it. the latter is definitely something for me to think about. thanks once again!