Audio on the iMac (Teach me some cool Garage Band tricks)?

Invest in an audio interface such as the Lexicon Alpha or M-Audio Fast Track. There are hundreds of options, but these are two that seem to meet your needs.

You are attempting to wire your setup with incorrect voltages and impedance levels. The guitar is mono instrument level, the iMac input is stereo line level, and the microphone is either very low voltage or no voltage at all (requiring an external power supply).
An inexpensive audio interface will solve all of these problems, and furthermore, give you more features such as multitrack recording.

In almost all cases, GarageBand is a better DAW than Audacity on a Mac. The user interface of Audacity is complicated and ugly and may give the illusion of being more featured, when in fact GarageBand has support for more useful features such as realtime AudioUnit plugins, MIDI, and time signature quantization.

Thanks @Vortico!

Interested in talking drum sequencers? Haven’t had a chance to play with drum tracks. However, I know I’ll be wanting do do my own custom kit and sequences. What’s the fast path to go from drum sequence concept -> mixed stereo drum track? It would be nice to have each piece of the kit on a separate track to give more mix flexibility. Is this feasible with the stock set of tools?

Sure! GarageBand has built-in drum sequencing capabilities, but I’ve never tried them out thoroughly. To use them in your project, add an instrument track, and load one of the factory drum patches found in the sidebar. Each sample is triggered by a MIDI note in the chromatic scale beginning at C3.

You will have almost no configurability, but this will get you started. If you want to use your own drum samples, you can try the plugin database search at KVRAudio for a near complete list of AudioUnit plugins you can buy or download.

GarageBand’s sequencer is terrible. What I would actually recommend for drum tracks is to download some one shot samples and arrange them over 3 audio tracks, cutting and pasting to get them to do what you want. That way you can compress and edit each parts of the tracks without having to deal with Garagebands template based master tracks.

My honest suggestion, though, is to start looking for something else. Garageband is great for simple recording and playing with (learning about compression, filters, etc.) but when you do ultimately move on to something like Logic Express or Ableton Live you’ll wonder how you ever fought with Garageband for so long.
When you do buy an audio interface such as the ones @Vortico mentioned, it’s a good idea to look into some other DAWs too; Garageband is a lot more difficult than it should be.

Just a follow up. I played around with Garage Band’s sequencer last night and didn’t find it all that bad. I was able to do exactly what I wanted, which was to put each individual drum from my “kit” onto a separate track. Further, I found that I could tap out the groove for each individual part on my keyboard and was then able to go in and fix up any little imperfections with the “piano scroll” editor. All in all, it wasn’t nearly as painful as I expected.

I then added a bass line using a similar technique, and while there is no substitute for a live player, the canned sound did not totally suck. It even had the added touch of that wispy sound of one’s fingers sliding up the strings between notes.

Kudos to the good folks at Apple.

Ok, just a follow up in the hopes that somebody is still following.

I plunked down around $150 for a 2 channel USB input (sorry, don’t recall the brand off hand as I am at work at the moment). This particular model sports two “hybrid” input jacks that accept either ¼” plugs or the 3 prong mic cables. I laid down some sweet guitar tracks and was thinking how this was $150 well spend. Then I went to do some vocals. I plugged in my Audio Technica mic and found that even if I cranked the input up all the way I still was getting barely audible input (along with a bunch of distortion).

Is there some sort of hidden config setting where I can crank up the input level in either the Garageband application or the iMac system settings?

@YoBob In the audio midi setup app found in your utilities there should be a little something like this.

The sliders should be set to around 15 DB by default; anything more than that will clip like a bitch on my interface. Play around with that if you want, but if it doesn’t work set it back to 15DB.

Also, make sure your mic doesn’t require phantom power, as most $150 interfaces don’t provide it.

If none of that works, you might just want to drench your vocals in compressor and gain plugins in garageband.

@dverhey is right. You most likely need +48v phantom power to use that mic. Did you own and use the mic previously to buying the interface? You can use an external mixer with phantom power or power supply to plug into the interface.

Thanks for the advice y’all. Turns out my mic was fried. Picked up a new Sennhizer on the way home from work. Much better!