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View Full Version : Speakers amplifying laptop CD ROM spin sound - what the heck?


singularity2006
12-20-2003, 05:04 AM
I'm using an old Fujitsu CSL laptop w/ a .... 12x CD ROM (I think it's a 12x). Anyhow, I've plugged in external speakers to the thing but the funniest thing happens now.... whenever the CD ROM is spinning up to read a disc, the spinning noise is actually outputted to the speakers too. The audio line btw, is right next to the CD ROM. Any idea why this is happening?

And btw, it's not coming out like static. It's coming out loud and clear - the whizzing sound of a CD ROM spinning up.... real strange. And it's not like the CD ROM is just extra loud either. I've turned the speakers on and off to notice the sound.

Ideas??? It's not necessarily a problem or anything since I don't use the CD ROM that often, but it's just such a weird phenomena!

RusMan
12-20-2003, 05:11 AM
Check your microphone if you have one, it might be on.:hmm:

singularity2006
12-20-2003, 05:12 AM
no microphone. The line-in and microphone have both been muted.

Novakog
12-23-2003, 05:02 AM
Believe it or not, most audio lines (particularly headphone style (3.5 mm?) jacks) actually output sound, as opposed to a digital signal or something. Next time you go on an airplane, turn the volume on the "radio" up real loud and you can hear it without headphones. Anyway, the point is, that the CD-ROM sound is actually being transmitted through the speaker wire or whatever.

That's why Creative made that external SoundBlaster card or whatever, because the output lines of a PCI slot audio card can get a lot of sound interference from all the gizmos in a computer.

singularity2006
12-23-2003, 07:12 AM
wow, really? Can you explain in more specifics how that works? That's pretty fascinating stuff to have sound interference get converted into a transmittable signal in the wire like that.

Novakog
12-23-2003, 08:58 AM
No no, what I meant is that the "signal" is actual sound going through the wire, like those styrofoam cup + string "telephones". If you turn volume up super high on a cd player or something, you can actually hear sound coming out the headphone jack when you put your ear to it. In other words, there is no signal. What's travelling through the cable is literally sound.

I'm not sure if this applies to all types of audio cables and such (certainly not the optical audio outs, which don't have that interference, which is why they're so optimal to use), but it sure seems to be the case here.

imashination
12-23-2003, 09:18 AM
Wow, the blind really do lead the blind. This is 100% pure rubbish.

squidinc
12-23-2003, 12:24 PM
Originally posted by Novakog
No no, what I meant is that the "signal" is actual sound going through the wire, like those styrofoam cup + string "telephones". If you turn volume up super high on a cd player or something, you can actually hear sound coming out the headphone jack when you put your ear to it. In other words, there is no signal. What's travelling through the cable is literally sound.

I'm not sure if this applies to all types of audio cables and such (certainly not the optical audio outs, which don't have that interference, which is why they're so optimal to use), but it sure seems to be the case here.

I suggest you actually do some research before responding to a thread :surprised

stephen2002
12-23-2003, 01:23 PM
Originally posted by imashination
Wow, the blind really do lead the blind. This is 100% pure rubbish.

Not 100% rubbish. The reference to the airplane is correct; with most of the jacks that I have encountered on airplanes the speakers are embedded into the arm rest and the "headphones" are just rubber tubes to get the sound to your ears.

However in an airplane is the only place I have ever seen that technology. All other speaker cables use eletrical impulses to either drive speaker motors directly (in the case of headphones) or to drive an amplifyer.

nobrain
12-23-2003, 05:05 PM
to fix your problem, try replacing all replaceable sound cables with ones that help shield out interference

imashination
12-23-2003, 05:22 PM
Originally posted by stephen2002
Not 100% rubbish. The reference to the airplane is correct; with most of the jacks that I have encountered on airplanes the speakers are embedded into the arm rest and the "headphones" are just rubber tubes to get the sound to your ears.

However in an airplane is the only place I have ever seen that technology. All other speaker cables use eletrical impulses to either drive speaker motors directly (in the case of headphones) or to drive an amplifyer.

Sorry, you are correct, in some older (I haven't seen this used in the past few years) aircraft they literally pipe audio through tubes like a stethascope. That makes the other reply 99.9% rubbish then ;-)

In reply to the original post, I think to be honest you just have naff audio on your laptop, especially condering its age. One of the reasons I sold my laptop is because of the poor audio. Interferrence would come from anything and everything, including the CD drive.

In fact, you can all try this, if you have onboard audio, crank up the volume and move the mouse slowly. Often you will be able to hear the mouse interrupt signals as the mouse pointer moves each pixel.

Novakog
12-23-2003, 07:33 PM
Alright well, that's just the impression I got from airplanes then. And, I wrote that post at 2:00 in the morning (without caffeine :surprised), blame my stupidity on that, sorry Singularity.

Anyway, like he said, how would a sound "add" itself to an electrical impulse unintentionally (unintentionally by humans I mean, not the laws of physics ;)) in the electrical form that would represent its own actual sound on the speakers. I'm very fascinated in this.

singularity2006
12-24-2003, 12:29 AM
so the EM produced by the spinning of the CD tray is emitting a pulse absorbed and transmittied by the audio cable within the immediate vicinity?

Anyhow, I'd get insulated cables if I thought it was necessary. GeY laptop. It only does word processing and internet and plays music. That's all I need for my room. My real power lies in my workstation on the other side of the house. ^.^

paultheplumber
12-27-2003, 09:11 AM
My old ('91) car stereo tuned to a certain AM station would pick up the sound of my power windows. But I guess that is a somewhat different matter...

Novakog
12-27-2003, 07:00 PM
Wow, that's kinda cool though.

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