How do I play my guitar through Garageband using the MacBook Pro Dual Audio Out/In?

I've tried iMic but found it very noisy, the sound seemed thin and it seemed to pick up external sounds as well, so for example if I knocked the iMic slightly I could hear the knock in my headphones. It worked but the sound was so low quality I gave up on it eventually. I haven't tried anything since but I do intend to get a more expensive adaptor at some point.

Your computer has no audio in (the 1/8" jack is not a combined in/out port), so you do need an audio interface to get the sound of the guitar into it.

I copied this from the MacBook Pro spec page "Support for Apple iPhone headset with remote and microphone".

So it may have audio in but not the usual type.

Still a interface is by far the best way to go.

I use an iMic from Griffin Technology. In the US, they seem to retail for about $25, so way less than £50. I'm not a super audiophile, but I researched it a bit before buying it, and in my (admittely rare) use of it, it has seemed to work fine.

First of all, yes, an external audio interface is most of the time better than the built in ports/microphones.

However there seems to be some confusion about that single audio jack on the MacBook Pros (I guess that's the one you have).

It is a single 1/8" jack and although it has a headphone label on it, you can use it as an audio input. The Sound tab in the System Preferences has a popup menu where you can select if you want to use that port as a Sound Output (for headphones) or as a Sound Input (plugin your keyboard or guitar).

Please note that the options on this Sound settings window is "dynamic". Usually it only lists the Built-in Microphone as the single input device. When you plug in your guitar and select the Sound Input, then it switches and displays now "Audio line-in port". (that's what you see on my screenshot).

So technically you play your guitar through GarageBand by just plugging it straight into your MacBook Pro with a 1/4" to 1/8" cable. The signal is week, so you might want to crank up all the level settings.

Hope that helps

Edgar Rothermich

http://DingDingMusic.com/Manuals/

'I may receive some form of compensation, financial or otherwise, from my recommendation or link.'

That's only true for older models, in for at least two years MBPs haven't had this dual input/output.

The screenshot (with the dual input) is from my MacBook Pro 13" that I bought January 2012.

Edgar: I stand corrected.

Edgar:

I can attest that your solution works on my MBP (2011) as well. It's both audio in/out, and I can use them simultaneously with the right gear (iPhone headphones, aux in/out splitter, etc.).

However..

I need some tips on how to set up guitar recording and playback with headphones.

Set up #1. I just plug in my acoustic electric guitar to my MBP directly with an 3.5 mm 4-Pin aux cord (with an 3.5 mm Mini to 6.3 mm 1/4 inch headphone adaptor in the guitar jack). Then I switch the Sound setting to use Audio port for Input. This form of set up feeds power to my guitar (I think) so the guitar mic works, allowing me to record on Garageband.

This setup would be adequate, but my acoustic is louder than my MBP speakers, thus any of the sweet pedals can't be adjusted properly. What I need is my headphones and guitar to use the same jack. So I got a splitter.

Set up #2. I use a 3.5 mm 4-Pin to 2x 3-Pin 3.5 mm Headset Splitter Adaptor - M/F. The splitter is plugged into the audio port.

The guitar connection is sort of the same as #1, but the aux cord is plugged into the microphone side of the splitter and my headphones are plugged into the headphone jack of the splitter. This fully functions in recording and headphones when I turn on my built-in guitar tuner, but then it automatically shuts off for the battery.

Unlike #1, #2 set up doesn't automatically work to power my guitar, but like I said, it only works as long as my tuner stays on. There must be a way (a setting, or something) to make this set up work.

I know this is complicated, but it's been fun figuring out how all these things function. I'm almost there, but I could use some fresh ideas on how to combine the functionality of #2 with the power of #1.

iMic has been great for me, combined with some good headphones and a macbook pro i'm in heaven. you have to activate the midi in Applications > Utilities to make it work, if I recall correctly:

Record with iMic in GarageBand - Apple Support