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Juggler · Jun 22, 2002, 02:31 AM

Is there any software that reduces the speed of the cd-rom? My new ibook's cd-rom is extremely noisy when playing back audio cd's. I suspect that, being just audio, the cd does not need to spin that fast. But how to slow it down?

Is it my imagination or playback of audio cd's becomes noisier after you burn your first cd?

As you can tell, I have a combo drive. My ibook is the newest 700 Mhz model.

Thanks!,
Juggler.

rjenkinson · Jun 22, 2002, 03:16 AM

i was under the impression that audio CDs are played at 1X.

anna katzner · Jun 22, 2002, 05:47 AM

(caution: this may be complete BS)

i guess you're using iTunes to play your Audio-CDs.

maybe using the "old-style" AppleCD Audio-application (OS 8-9) might help?

(it's not installed by default anymore, but you will (probably) find it in the "CD Extras"-folder on the "iBook Install CD" (OS 9) that came with your iBook)

i remember seeing "AppleCD Audio" somewhere on an installer-cd and thinking: "hey, nice, that old thing's still there...: ) "

(i can't test it right now, as that particular CD is in my office but i just checked my CD-Archiver ("CDFinder", nice proggie by the way) and it's definitely on the install-CD that came with my iBook/600/combo)

so maybe iTunes reads/renders Audio-CDs differently than the old-style "AppleCD Audio"...

...but then again - this could be (see above) <img border="0" title="" alt="[Wink]" src="wink.gif" />

hth, anna

wunderkind · Jun 23, 2002, 12:54 AM

Juggler, is a Combo drive in your iBook from Toshiba or from Sony?

I have the one from Toshiba and it is very loud - discussed <a href="http://forums.macnn.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=13;t=003605" target="_blank">here</a> .

From what I read on Apple discussion boards, Toshiba drive is very good at playing DVDs, but loud with audio CDs. In contrast, Sony drive is very quiet, but skips DVDs.

Juggler · Jun 24, 2002, 01:45 AM

Following your advice folks, I booted into OS 9 and tested an audio CD with iTunes. What I found out is that the noise disappears!

It is not completely quiet, of course, but its descent (much quieter than in OS X). What this suggests is that the problem is not with the CD-drive itself but rather with the operating system.

This is probably good news for us iBook 700 Mhz owners since, if we bug Apple enough, maybe they will correct the problem with a software update.

Another observation: When in OS X, and judging only from the noise, it seems that the CD drive spinning speed is the same when importing songs from and when only listening to an audio CD. This confirms that OS X is spinning the CD at more than 1x, even when it is only performing audio playback.

Answering wunderkind's question, my CD combo drive is Toshiba. Judging from his remarks above, Apple must have screwed-up the configuration files for the Toshiba but not for the Sony driver.

Juggler · Jun 24, 2002, 01:51 AM

In conclusion, it seems that the following are true:

In 700 Mhz iBooks with Toshiba CD drives, Mac OS X is spinning the audio CDs unnecessarily fast (maybe 3x - 5x).</li>
This is a software issue because in OS 9 the same Toshiba CD-drive spins at normal speed (1x).</li>
Every iBook 700 Mhz owner is going to complain to Apple and they will fix the problem in a future system update.
</li>

Of course, it would be interesting if other iBook owners (with Toshiba drives) can reproduce the difference in CD audio playback spinning speed when in OS 9 versus X, as I am reporting. <img border="0" title="" alt="[Wink]" src="wink.gif" />

[ 06-24-2002, 01:52 AM: Message edited by: Juggler ]

Dan Szwarc · Jun 24, 2002, 07:15 AM

I believe you'll find that the CD spins at more than 1X because of the digital audio playback (started with the DA PMsa few years ago).

Since Apple has eliminated the Ananlog-in side of Macs, they also eliminated ordinary analog playback of audio cds (where the CD-ROM does the D-to-A conversion and outputs an analog signal to amplifier circuitry). So to read the digital data and convert is to analog through the computers circuitry the CD spins at more than 1X.

Is it necessessary to spin at more than 1X? I'm not sure. Could Apple quiet these puppies down? Obviously.

Juggler · Jun 24, 2002, 12:16 PM

Interesting point Dan. I believe that OS 9 has digital audio playback as well. Therefore, if OS 9 can play audio CD's quietly (with the Toshiba drives) I see no reason why Mac OS X can't do it.

Juggler.

ccsccs7 · Jun 25, 2002, 03:50 AM

I'm wondering if the versions of iTunes between OS 9 and X are in sync. If the iTunes is importing a CD, it spins the CD at a much higher rate.

Hey! I just noticed something. In OS X start playing a CD in iTunes. Now, go to the Finder and open the CD. Double-click the last track of the CD. The spin slows down dramatically. The CD spins faster at the edge of the CD, and slower towards the center.

This discussion is beginning to sound familiar, but I'm not sure.

Here's a cool trick. Try playing one track in iTunes, and another in QuickTime Player. I wouldn't suggest doing it too much though. It might wear out your drive prematurely.

Theor(y/ies):

Mac OS X handles drives differently. Perhaps some applications rely on standard parts of the OS to handle file access. Applications can't/don't control the drive itself.

Perhaps 9 allows more unrestricted access to hardware. I tried launching AppleCD Audio Player in the Classic environment under X and it doesn't run.

A VCD playing program wouldn't run because Mac OS X didn't support the particular file structure of a VCD. This suggests that X needs more work.

Dan Szwarc · Jun 25, 2002, 07:32 AM

<blockquote>quote:<hr />Hey! I just noticed something. In OS X start playing a CD in iTunes. Now, go to the Finder and open the CD. Double-click the last track of the CD. The spin slows down dramatically. The CD spins faster at the edge of the CD, and slower towards the center.<hr /></blockquote>I think you mean that vice-versa-ed. The last track on a CD is on the outer edge. The first track is near the center.

During normal analog playback (in a cd-player, not CD-ROM), a CD changes its spin rate depending on the location of the laser. This is because CDs are CLV disks or Constant Linear Velocity. This means that the data is read at a constant rate throughout the ever increasing spiral diameter and to do this, the cd must spin slower as the head gets to the outside.

Ever notice the "maximum" rating on a CD-ROM? That's the data speed at the outer edge of the CD with the CD spinning at a constant angular velocity. Inside its about half the maximum (I'm just guessing).

I think this is a software issue. Todays machines don't need 32X to playback cds digitally, but the software may limit the speed of rotation. If the CDs were quieter this wouldn't be an issue.