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Awful static when plugging MBP into speakers

L

littlevish

macrumors member
Original poster
Oct 18, 2007
92
0
Just received my new 15" i7 Macbook Pro today, and I like it a lot, but I'm having one major issue. I get awful static when I plug it in to my speakers via the headphone jack. I had no issues with the speakers on my previous Macbook (from around 2007). I even used the speakers just this morning with the old MB.

The static comes whenever a sound is played, whether iTunes, a system sound etc. If there is no sound for a few seconds, it goes away, but immediately comes back the next time there is a sound.

The static is fainly present using my Sennheiser headphones, and also with the built-in speakers. But the sound is horrendous with external speakers.

I've seen a lot of people with similar issues while searching the web, but no real solutions. Does anybody know?
 
The static is there anytime a sound is played on the system. So yes, it remains.
 
Don't know the name, but it's a Dell system that my dad had bought for his PC and never used.

It's 5.1, but I've always just used it as stereo.
 
Have you tried a set of headphones or other set of speakers with your MBP?

If another set of headphones or speakers gives the same static, then it's time to take the MBP back for warranty work.
 
I turned my headphones way up...and the static is faintly there.

This sucks, but it seems pretty common. Is this fixable?

What I mean is, I've seen this a ton when googling...all MBP's don't suffer from the same thing?
 
i have a pair of sennheiser hd 555's that i use for music/movies on my mbp. they sound superb :D but as for your case, i haven't the slightest clue what it could be. possibly ask the genius bar at an apple store? good luck! :apple:
 
I have issues when I plug it headphones into the mbp, it won't always recognize them right away. I have to unplug and plug them back in multiple times and it slows down my computer when I do that. Is this normal?
 
m85476585 said:
Try turning up the volume on the computer and turning down the volume on the speakers.
Click to expand...

This did help somewhat. I guess if I got an attenuator (sp?) I could eliminate it even moreso, but I can't help but feel weird fixing a $2000 computer like that.
 
My 2008 MBP needs an attenuator for my headphones (but I still don't have one, so I listen to noise and distortion), but I thought they fixed the problem in the new MBPs. You could try to get Apple to fix it, but my guess is they will claim it's normal or that they can't hear it.
 
I'm still not convinced that I hear it through the headphones. I think it may have been the songs I was listening to. The static on the speakers is so horrendous even with just the blips from adjusting the volume that I have a hard time believing I wouldn't hear that with my headphones.

The noise wasn't present at all when plugging into my dad's computer speakers.

I still don't think my own speakers are at fault because they work fine with my other Macbook, yet it doesn't seem as if the MBP is really at fault either.

But since it only happens with these speakers, I have a feeling nobody will listen if I try to take this in to get it fixed.

I'm lost right now...
 
Is it static (like noise) or a hum? If it's a hum at ~120Hz it might be a ground loop (search for it, I've listed possible ground loop fixes before).
 
Definitely not a ground loop. It's too high frequency for that. I had my grandpa who is a big audio guy come look at it, and he confirmed that. One of the cables to the stereo system was faulty, but that turned out not to be the problem. So we simply fixed something unrelated to the larger issue.

I might just record a video of the issue, as I'm convinced that this static is too loud to be normal.
 
Does it also happen when the computer is not plugged in and running on battery power?

You could try a cable to record the headphone output on the line in and see if you can hear any noise (you will need to amplify the signal the line in hears, but if you do it too much you will get noise from the line in itself). If what you record sounds the same as what you hear over the speakers, it's a problem with the computer.
 
Yes, it happens regardless of whether it's plugged in to the power source.

I tried recording line-in, and I'm still not sure. There is some noise on the recording, but it has to be amplified quite a bit to hear, so I'm inclined to think that it's not the same noise I'm hearing through the speakers. The noise through the speakers is very easy to hear.

Update: So apparently it was a ground loop after all. Such a relief to know it's not the computer. A ground loop isolator did the trick.
 
It's interesting that you could have a ground loop if the computer is running on battery power. Maybe the ground loop isolator is doing something else that happened to fix it. As far as I know, ground loop isolators are basically isolation transformers that block DC and pass AC, and isolate the lines on either end. I don't fully understand this kind of circuit, though.

Maybe the problem was common mode noise
http://en.wikipedia.org/wiki/Common-mode_interference
since isolation transformers should block that too. You would never hear it on headphones, but the amplifier in your speakers could pick it up. A good amplifier should be able to reject common mode noise, though, and your MBP shouldn't even be putting it out in the first place (if the audio system was properly designed and working right).

I'm just curious, what kind of speakers are you using?
 
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