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Rip CDs at Mach 2 on a Mac Pro Apps
I've got a huge collection of music, and I still haven't ripped all my CDs; in addition, I constantly buy new CDs, and rip them as soon as I get them. So when I got my new Mac Pro, I was hoping that the iTunes import speed would be substantially higher than on my previous Mac, an iMac G5.

A hint last year mentioned one way to speed up ripping, and there are others: turn off error correction (but risk getting diginoise in your music files), and quit extraneous applications to make sure that iTunes gets as much CPU time as possible.

But with a Mac Pro, another option is available: add a second optical drive. The built-in DVD burner reads CDs at up to 32x; this translates, on my Mac Pro, to an average of about 15x ripping in iTunes. So I bought a cheap CDR drive (not a DVD/CD drive) that reads CDs at up to 52x. The results are stunning: I now rip CDs at an average of over 30x, hitting over 40x at the end of the disc. (Ripping speeds are always slower at the beginning of a CD, because the CD itself turns at the same speed, but since there is less data per revolution near the middle, at the beginning of the CD, the drive simply reads less data.)

The only downside to this is the noise that the drive makes; but at less than 2 minutes per CD, it's more than acceptable.

And, before you ask, you cannot rip two CDs at the same time, at least not with iTunes. However, if you use an additional ripping program, you should probably be able to rip one with iTunes and the other with that program. I haven't tested that.
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Rip CDs at Mach 2 on a Mac Pro
Authored by: sjmills on Oct 27, '06 08:18:59AM

CDs and DVDs don't spin at a constant rate. They need to spin faster when reading the inside and slower when reading the outside. This is because the data rate must be constant (equivalent pits are the same length on the inside as they are on the outside). Or maybe I didn't understand what the OP was saying.



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Rip CDs at Mach 2 on a Mac Pro
Authored by: kirkmc on Oct 27, '06 08:32:13AM

I don't think the spin speed changes (at least not for sequential reads such as those that occur when importing music, or when copying one big file from a CD); I can hear when the speed changes, and that doesn't happen.

Also, if that were the case, you wouldn't see different import speeds in iTunes between the beginning and the end of a CD. Import speeds are always faster - as much as twice as fast - at the end of a CD.

Kirk



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Read my blog: Kirkville -- http://www.mcelhearn.com
Musings, Opinion and Miscellanea, on Macs, iPods and more



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Rip CDs at Mach 2 on a Mac Pro
Authored by: kirkmc on Oct 27, '06 08:36:19AM
From http://arstechnica.com/reviews/1q99/truex52-1.html:

"Newer drives are CAV, or Constant Angular Velocity, drives. With CAV, the rotational speed of the disc is constant. Since the data track has a smaller radius on the inside of the disc, if speed remains constant as the read head moves inward, the amount of data read during a rotation of the disc will be smaller than at the outside of the disc. Thus we get a range of speeds. A typical 40X CAV drive is really a 16X-40X drive--16X at the inside, 40X at the outside. Few manufacturers go to great lengths to point out this fact, publicizing only the highest rate."

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Read my blog: Kirkville -- http://www.mcelhearn.com
Musings, Opinion and Miscellanea, on Macs, iPods and more

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Rip CDs at Mach 2 on a Mac Pro
Authored by: Unsoluble on Oct 27, '06 01:41:48PM

Interesting to see that the newer drives run at a constant speed. Not sure when they changed that, but I've got a Discman here from a few years back that has a little window in it, and you can quite easily see the rotational speed changing drastically from start to finish.



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Rip CDs at Mach 2 on a Mac Pro
Authored by: dethbunny on Oct 27, '06 02:25:35PM

It depends on the needs of the drive. If you play an audio CD in a computer, it'll keep playing at a constant data rate, while spinning more slowly at the end. Think of it this way - if the drive can spin at 5000 RPM and read data at 15X (totally made-up numbers there) in the middle, why artificially slow down to keep reading at 15X all the way through? Why not spin at 5000 RPM all the way, and reap the speed gains as the tracks get gradually longer? That's what modern drives do. Since it's generally desirable to read data as fast as possible, they maintain a constant angular velocity that is always as fast as a particular disc can be reliably read.



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A primer on CLV vs. CAV
Authored by: Lectrick on Oct 27, '06 08:34:02AM
http://en.wikipedia.org/wiki/Constant_linear_velocity

CD's use CLV (Constant Linear Velocity) which basically means that the same amount of track per second (1.2 meters/s) passes under the read head no matter where the head is on the CD. So I'm not sure why iTunes rips faster towards the end of the CD.

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In /dev/null, no one can hear you scream

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A primer on CLV vs. CAV
Authored by: j-beda on Oct 27, '06 09:35:15AM

<I>CD's use CLV (Constant Linear Velocity)</><P>
Deeper digging in wikipedia shows that audio playback uses CLV, but it looks like high speed CD-ROM drives use "constant angular velocity" or some sort of "zoned" CLV, thus allowing for higher data rates for data on the outer tracks of the CD.



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A primer on CLV vs. CAV
Authored by: dethbunny on Oct 27, '06 02:17:57PM

The disc is recorded in CLV, but most any high-speed drive reads (and likely writes) in CAV. The limiting factor for a high-speed drive is vibration caused by disc balance issues. The more RPMs, the more the disc will wobble. The drive spins as fast as it can while still reading data accurately.

As the track is physically longer toward the outside of the disc, more data can be read per revolution. Since the drive is always spinning as fast as it possibly can and still read reliably, more track, and thus more data, goes by the read head toward the outside. Thus you get much better data rates toward the end of the disc than toward the beginning.



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Rip CDs at Mach 2 on a Mac Pro
Authored by: Anonymous on Oct 27, '06 09:40:52AM

52x CD readers are spinning at the maximum rotational speed. Because the disc is stamped at CLV to achieve highest data density, the data will rip faster at the END of the disc.

If it spun any faster, your CDs would break.



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Rip CDs at Mach 2 on a Mac Pro
Authored by: kirkmc on Oct 27, '06 10:06:02AM

Is this really the limit for CD drives? Are you sure?

If so, rats! I was looking forward to a 128x CD drive... :-)

Kirk

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Read my blog: Kirkville -- http://www.mcelhearn.com
Musings, Opinion and Miscellanea, on Macs, iPods and more



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Rip CDs at Mach 2 on a Mac Pro
Authored by: dethbunny on Oct 27, '06 02:21:01PM
CD drives have been stuck at about 52X for five years or more now. It seems the one hope of making them faster is no longer a factor - Kenwood TrueX drives were very very fast, quiet, and achieved speeds of 72X plus by splitting the read laser and simultaneously reading something like 7 tracks' worth of data.

http://www.techreport.com/reviews/2000q3/kenwood72x/

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Rip CDs at Mach 2 on a Mac Pro
Authored by: drewk on Oct 27, '06 09:55:12AM

While iTunes will not import multiple CDs in parallel, it WILL do them in serial and automatically.

Go to Preferences / Advanced / Importing. With the "On CD Insert" pulldown, select "Import CD and Eject."

iTunes will rip the CD as soon as you stick it in and then eject it. With two fast CD drives your can do a pile of CDs in very little time.



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Rip CDs at Mach 2 on a Mac Pro
Authored by: swammifool on Oct 27, '06 10:23:32AM

You can rip from both drives at once if you create a second user and switch back and forth bewteen them using fast user switching, with each instance of iTunes ripping each CD. You most likely dont want to make them rip automatically if you do it this way, but using the two-user system, I ripped about 800 CD's in a marathon session one day on a MDD. Just FYI.



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Rip CDs at Mach 2 on a Mac Pro
Authored by: kirkmc on Oct 27, '06 10:24:57AM

That almost deserves a hint of its own!

Kirk

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Read my blog: Kirkville -- http://www.mcelhearn.com
Musings, Opinion and Miscellanea, on Macs, iPods and more



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There need to be a better way...
Authored by: themacthinker on Oct 27, '06 10:36:15AM
I think there need to be a better documented way on how to burn natively on os x.

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Rip CDs at Mach 2 on a Mac Pro
Authored by: Electricbacfac on Oct 27, '06 03:47:17PM

The bit about data on the rings of cd's is incorrect. As you proberbly know, they read centre out. However the shorter rings at the centre contain exactly the same amout of data as the longer outer rings.



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Rip CDs at Mach 2 on a Mac Pro
Authored by: kirkmc on Oct 28, '06 12:12:19AM

Sorry, that's totally wrong. The pits and grooves are the same size across the disc. So, just like on LPs, there is a different amount of "data" where the circumference is shorter. Since CDs are read from the middle out, there is less data per "ring" at the beginning than at the end.

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Read my blog: Kirkville -- http://www.mcelhearn.com
Musings, Opinion and Miscellanea, on Macs, iPods and more



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Rip CDs at Mach 2 on a Mac Pro
Authored by: dsomar on Oct 29, '06 09:37:32PM
Yes, but what I really want to know is, can you now rip two CDs at once? Does anyone know if this is possible on one machine? Apple or Win, but preferable Apple...

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