The following tutorial shows you the step by step guide on how to get MP3 from your favorite CDs as iPhone Ringtone on Mac
First, Get music from your CD on Mac for free in iTunes.
Step 1. Insert your CD to your Mac or iMac.
Step 2. Open iTunes to import CD songs .
After you open iTunes, you'll be notified automatically “ if import the CD songs to iTunes library”. Of course, you can also click “Import CD" to get CD songs.

Before importing CD songs to iTunes library, you can also set some import settings by the showed "Import Setting" button , there are five encoder ways for selecting.
After choosing the Encoder, Click "OK" to finish the Import Setting.

Step3. Get the songs from CD.
You can find the songs of your CD in Music items of iTunes Library, then you can use those songs to make iPhone Ringtone on Mac.
Now let’s see how to convert songs from CD in iTunes Library to iPhone on Mac.
Having found the CDs songs in the iTunes Library, now you can make your preference ringtone for your iPhone on Mac, even Snow leopard in the following simple steps.
Want to Make CD MP3 as Ringtone for your iPhone, what you need is iPhone Ringtone Maker for Mac, just download it from its websites.
Step1. Add the CD songs into iPhone Ringtone Maker
After open Ringtone Maker, double click the Music item on the left interface or just drag directly to the program for making ringtone.

Step 2: Trim CD songs for your iPhone ringtone
Drag and drop the slide bar to appoint the start point and end point for your iPhone ringtone length. Alternatively, you can type exact time value into time-setting box. You can choose to preview the whole audio or video or just the trimmed part.
Step 3: Generate iPhone Ringtone
After trimming, click "Start" button to generate the ringtone. The edited ringtone will be saved on ringtone category of your iTunes.
You can also Make Free iPhone Ringtone with iTunes with complicated steps.