Loud hum on optical drive?

[Reading Bug]

Hi all,

I've recently noticed one of the two drives in my Mac Pro making a loud, mechanical-sounding humming noise occasionally while burning DVD-R. They're both Pioneer drives with NEC chipsets, late 2008 model.

The drive in question has only recently been louder (maybe the last two discs; I don't burn a ton), and it only happens when it seems to be communicating with the computer. With the Pro towers, it can sometimes be hard to tell from what area of the machine a noise is coming (the computer is generally a little louder now that it's older). At moments it sounds like it could be the drive's motor, but it isn't constant and for some of the burn session, everything sounds normal. Please note this is not the usual sound of the drive gearing up and slowing down during a session.

This drive is my backup and, though more than five years old now, probably hasn't even been used for 100 hours. The main drive doesn't make this noise. I'm a little concerned as I know these exact drives aren't made anymore.

Assuming this is enough information, would such an issue be related to communication between computer and optical drive, or would it be something wrong with the drive itself? Even with the noise, it seems to burn normally (still need to do verification on the most recent discs though).

Much thanks!

[dpalomaki]

What you describe sounds like bearing wear that may be sensitive to certain rotation speeds. The drive is pushing 7 years old and probably getting to be time to replace it, the processes that cause the noise may also cause issues in the resulting recording. If the noise continues I would replace it. New drives are not expensive - maybe get one that is BluRay capable.

[Reading Bug]

Thank you, dpalomaki. Would you explain more about bearing wear please? Frankly I'm a little skeptical physical wear is the issue, as the drive has simply not been used much. Neither one has really - nowhere near the 2,000 hours cited here at the forum for drive failure. I'm actually looking to use this backup drive more so it keeps pace with the main one in regards to wear.

To provide a bit more info... the last time I inserted a blank DVD-R, it caused the noise almost immediately. It faded a little, then came back stronger momentarily when the drive slowed and picked up again during the burn (which is apparently normal for these drives; seems like a recalibration thing). When the drives pick up again, it's typical for them to sound louder as it's like it's reading the blank disc for the first time. But on the last burn, the hum started in at the same time, making the whole thing unusually noisy. So in other words, the hum was at its loudest when the normal operation of the drive was at its loudest too. But again, there were moments during the burn session when everything sounded totally fine.

They're 16X drives, but the DVD-Rs are 8X. My burn options are therefore 4X, 6X and 8X. I burn at 6X and always have on both drives.

P.S. Thinking about its use over the years, I would say the drive in question (the backup) has operated for maybe about 10 hours total. At the most.

[dpalomaki]

Time to failure for mechanical items are estimates and some will fail early, a few much earlier, than the average. You could have received a drive with a marginal bearing that wore out early. In some respects the luck of the draw. The sound is caused by something moving - and unless you have a lot of noisy or out-of-center (unbalanced) media, what is left to make noise is the drive internals.

If the same disc is OK in another drive, than what is left is the drive itself. Discs recorded or read on the drive that is making the noise may have a higher incidence of read or write errors. However, you are not likely to notice that until they reach the point of being uncorrectable. (With the right tools this can be tested.)

Why noise at only certain times/speeds? The discs spin at variable speeds depending on how the media is recorded, and it is possible that at certain speeds a resonant frequency is reached that will cause noise and increased wear. As the disc speed changes out of the resonant band the noise will reduce. Other factors such as temperature could also be a factor.

[lordsmurf]

I also doubt bearing/physical wear, given the details.

It may be a disc that is not 100% flat, which happens, and causing it to vibrate more. And not all drives were tolerant of vibration. Pioneer has two different models: with honeycomb, and without. The honeycomb dampened the vibration. One of the drives in my main system lacks the honeycomb as well, and it will make noise with some discs. It's the disc, not the drive. Samsung drives are notoriously noisy, and their construction is one reason those drives are/were so cheap.

The faster the spin, the worse the noise.

Temperature is a factor. If the drive is too hot, it makes the disc less rigid. That increases the (non-technical) wobble.

[Reading Bug]

I haven't had a chance to use the drive in question again, but am optimistic it is indeed the disc. I'll report back if any issues continue. Thanks LS!