Rip CDs Better and Faster

While many people get music from digital sources--the iTunes Store, eMusic, Amazon.com and other on-line vendors--a lot of us still buy CDs. In addition, many people have never gotten around to ripping their CD collections. Ripping CDs can be a chore, and ideally you want to rip as fast as possible, but it's not always easy to do so. Here are some tips for ripping CDs, and a way to get faster ripping speeds for your discs.

What affects ripping speed

There are two main variables when ripping CDs: your optical drive and your processor(s). The speed of the former has the greatest effect on CD ripping. I recently downgraded from a Mac Pro to a Mac mini, and the only lament I have is the speed of the internal SuperDrive in the mini, which reads CDs at up to 24x. With the Mac Pro's ability to hold a second optical drive, I had added a 52x CD drive, and ripping CDs in iTunes was very quick: I would get up to 40x, compared to a maximum of 20x on the Mac mini.

Ripping speed is shown in iTunes, at the top of the window, as an "x" speed. (1x is about 150 KB per second, or the speed at which data is read when listening to an audio CD.) I see figures from about 5x to 20x on my Mac mini, and these numbers increase as ripping progresses. This is not because iTunes gets better as it goes on, but simply because of the way CDs and drives work. When you copy data from them, CDs spin at a constant speed, or "constant angular velocity." Unlike LPs, which are read from the outside in, CDs are read from the center to the edge. Since the speed is constant, less data is read at the beginning of the CD than at the end, hence the increase in data throughput during the ripping process.

(Image Caption: iTunes shows you the speed at which it is converting audio data: here, it is ripping at 11x, or 11 times the speed at which data is read when playing back an audio CD. The "Time Remaining" is the amount of time estimated to rip the current track.)

Getting up to speed

The main way to improve the speed of data input is to get a faster drive. If you rip a lot of CDs, or are just getting around to ripping a big collection, it's a small expense to get either a second drive (if you have a Mac Pro) or an external drive that's faster than what came stock in your Mac. You can get external drives that read CDs at up to 48x, or internals that go to 52x.

Naturally, you won't get the maximum speed: with a 52x drive, I got up to 40x, meaning that near the end of a CD, iTunes would show me throughput of around 40x. But this speed increase is relative at the beginnings of CDs as well; you'll rip perhaps twice as fast with a drive like that overall. (The difference between the maximum read speed of 52x and iTunes' processing speed of 40x simply meant that the processors--or the way iTunes uses them--couldn't keep up with the data stream.)

The other variable that affects ripping speed is your processor(s). With a Mac Pro, iTunes never went to more than 100% of CPU time (that's considered to be 100% of one core, not of the four available cores; about one-fourth of the maximum). With the Mac mini, I get about the same processor hit: a maximum of around 100% (or half what the Mac mini can handle). With a faster Mac, only the most processor-intensive operations will slow down ripping, but if you have a slower Mac, working with other apps that hit the processor hard will slow down iTunes' ability to convert music files.

There's one other variable, that's more or less inexplicable. I've noticed, over the years, in a number of Macs, that Apple's SuperDrives tend to be very inconsistent. As I write this, I'm ripping a CD at about 10x, and the SuperDrive in my Mac mini is hardly making any noise. I've been ripping a box set of Schubert piano sonatas, so all the CDs are similar, and in some cases the ripping speed is fast, and the SuperDrive spins noisily, but in other cases it just goes slowly. I've had much more consistent results with other drives, notably second or external drives. If you plan to rip a lot, think of the cost of a second drive (around $60 for an external; half that for an internal drive if you have a Mac Pro), and the time you can save. While most listeners may not have dozens of CDs to rip at a time, fans of classical music and jazz, who buy box sets, may have piles of discs to rip, and saving a few minutes on each disc can make a difference.

Finally, iTunes can have an effect as well. Many users have reported faster or slower ripping speeds as new versions of iTunes have been released. These reports suggest that the speed problems are sporadic, but enough users have problems that you'll see complaints in forums. You may want to check whether you have Use Error Correction When Reading Audio CDs checked in iTunes' preferences (General: Import Settings). I always leave it checked, to make sure my rips are as reliable as possible, but in same cases this can slow down importing.

What about you? What type of ripping speeds do you see with iTunes, and on which kind of Mac?

Senior contributor Kirk McElhearn writes about more than just Macs on his blog Kirkville.

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