Many people want to bring records, cassette tapes, and other types of audio, into their computers and save them as MP3 or AAC files for later listening. Audio Hijack Pro is very useful for doing this, and we've outlined the steps for doing it here. With these instructions, you can important any audio into your computer.
First, you need to get the output of the audio device (your stereo, a microphone, etc.) into your Mac. Fortunately, almost all Macs have a Line Input port.* In most cases, you'll need a stereo mini-jack (1/8") patch cable coupled with a 1/8" to 1/4" adapter, like these from Radio Shack. No matter where you go, total cost to get the audio from your stereo to your computer should be under $10. Once you have the cables, just plug one end into the output of your stereo (the headphone jack works nicely) and the other into your computer's Audio In port.
Once you've done this, open up Audio Hijack Pro. Make a new Session, and set the Source Type selector, in the Input tab, to Audio Device. Select the proper audio device from the Select menu on the right - in most cases, this will be "Built-in Audio: Line In". Finally, adjust the Recording tab as desired, setting the file type and entering the desired tags.
Now you're ready to hijack and record. Click the Hijack button, and press Record. Then, start the audio playing from your source, and it will be recorded. That's about all there is to it. When you're done, turn the hijacking off, and disconnect the input device.
Assorted Notes:
-For recording audio off a record or cassette, using the Split button will seamlessly create a new audio file each time you hit it. Hit it in between tracks, and you'll wind up with different files for each song. You can also try using the Silence Monitor in the Recording tab to automatically split between tracks. Try the Analog preset to start, or experiment with a Custom setup.
-Many people also want to remove noise on the signal. As you may know, AH Pro supports VST and AU plugins in the Effects tab. With the low pass filter, you may be able to remove some hiss from cassettes. Other plugins such as Excitifier may allow you to improve audio fidelity. Experimenting o your taste will likely enable you to get the results desired.
However, if you're planning to do a lot of audio importation, you may wish to invest in a more professional solution. Check out Bias Inc's SoundSoap VST plugin. It'll plug right in to AH Pro and clean up all kinds of artifacts. It's not cheap at $99, but it will almost certainly serve your purpose.
*If your Mac doesn't have an audio input jack, you can use Griffin's iMic to gain an audio input.