27" iMac - High-pitched hard driving frequency with external speakers

[Bitwise]

I hope I'm not double posting. Have any of the other new iMac owners experienced weird frequencies coming from external speakers that are connected to their iMacs?

For example: I have a set of studio monitors that are hooked up to my iMac using a firewire audio interface. Whenever I'm copying data I get an extremely high-pitched frequency coming from my speakers that sounds like my hard drive spinning. Also, whenever I'm scrolling or moving the magic mouse I get a loud buzzing coming from the speakers (especially when scrolling). None of this stuff happened with my previous 20" iMac C2D. I have experienced this issue with all three of the 27" iMacs that I have gone through thus far (due to the yellow tint issue). Does this sound like something I'm just going to have to live with. All of these high pitched frequencies are driving me batty!

 

[slicecom]

I hope I'm not double posting. Have any of the other new iMac owners experienced weird frequencies coming from external speakers that are connected to their iMacs?

For example: I have a set of studio monitors that are hooked up to my iMac using a firewire audio interface. Whenever I'm copying data I get an extremely high-pitched frequency coming from my speakers that sounds like my hard drive spinning. Also, whenever I'm scrolling or moving the magic mouse I get a loud buzzing coming from the speakers (especially when scrolling). None of this stuff happened with my previous 20" iMac C2D. I have experienced this issue with all three of the 27" iMacs that I have gone through thus far (due to the yellow tint issue). Does this sound like something I'm just going to have to live with. All of these high pitched frequencies are driving me batty!

Yep, I've made numerous posts about this issue here and on Apple's discussions site.

http://discussions.apple.com/message.jspa?messageID=10723395#10723395

http://discussions.apple.com/message.jspa?messageID=10747236#10747236

http://discussions.apple.com/message.jspa?messageID=10748818#10748818

The new iMac's put out all sorts of RF and grounding interference. The best solution I've found so far is a powered USB hub between my iMac and audio interface. This eliminates the interference for me. Another solution is an extremely short cable (my 3" usb cable doesn't have any interference issues). The best solution (I have not verified this yet) seems to be one of these. You could also rip the ground pin off your iMac's power cord, not safe or recommended, but that would probably completely eliminate the noise too. Let me know if you find a solution that works for you.

 

[Bitwise]

Yep, I've made numerous posts about this issue here and on Apple's discussions site.

http://discussions.apple.com/message.jspa?messageID=10723395#10723395

http://discussions.apple.com/message.jspa?messageID=10747236#10747236

http://discussions.apple.com/message.jspa?messageID=10748818#10748818

The new iMac's put out all sorts of RF and grounding interference. The best solution I've found so far is a powered USB hub between my iMac and audio interface. This eliminates the interference for me. Another solution is an extremely short cable (my 3" usb cable doesn't have any interference issues). The best solution (I have not verified this yet) seems to be one of these. You could also rip the ground pin off your iMac's power cord, not safe or recommended, but that would probably completely eliminate the noise too. Let me know if you find a solution that works for you.

I'm using an M-Audio FireWire 410 audio interface, so connecting to a USB hub is not an option for me. In one of the links you posted I was reading that another person with a FireWire audio interface used some three-prong plug adapters with their monitors which seemed to resolve the issue. I will try this tomorrow and report back.

Thank you for the info. It was extremely helpful!

 

[Bitwise]

I'm very happy to report that the three-prong plug adapters completely eliminate all buzzing and radio frequencies for me.

 

[slicecom]

I'm very happy to report that the three-prong plug adapters completely eliminate all buzzing and radio frequencies for me.

Thanks for posting the update! I'll be looking for some of those myself. Did you plug your speakers into them, or the iMac? It's obviously the iMac creating the interference, so pluging just the iMac into them should theoretically eliminate the buzzing.

 

[Bitwise]

Thanks for posting the update! I'll be looking for some of those myself. Did you plug your speakers into them, or the iMac? It's obviously the iMac creating the interference, so pluging just the iMac into them should theoretically eliminate the buzzing.

I used them on my speakers. They're worth less than my iMac

 

[bchamorro]

I used them on my speakers. They're worth less than my iMac

I just ordered a 21.5'' iMac and will be using it with an Apogee Duet (Firewire) and Dynaudio BM5A monitors.

After reading this thread I got thoughts of canceling the order. I wouldn't be able to tolerate that noise you describe.

Should I cancel it?

 

[slicecom]

I just ordered a 21.5'' iMac and will be using it with an Apogee Duet (Firewire) and Dynaudio BM5A monitors.

After reading this thread I got thoughts of canceling the order. I wouldn't be able to tolerate that noise you describe.

Should I cancel it?

Don't cancel it, but order one of these too:

http://guitars.musiciansfriend.com/product/Ebtech-Hum-X-Hum-Exterminator?sku=150452&src=3WFRWXX&ZYXSEM=0&CAWELAID=26018345

If my theory is correct, plugging your iMac in through that will completely eliminate all noise. That's why I was asking Bitwise if he had tried plugging in just his iMac with a 3 to 2 prong adapter... could confirm my theory.

 

[tomacintosh]

Don't cancel it, but order one of these too:

http://guitars.musiciansfriend.com/product/Ebtech-Hum-X-Hum-Exterminator?sku=150452&src=3WFRWXX&ZYXSEM=0&CAWELAID=26018345

If my theory is correct, plugging your iMac in through that will completely eliminate all noise. That's why I was asking Bitwise if he had tried plugging in just his iMac with a 3 to 2 prong adapter... could confirm my theory.

Spending $70 on something that shouldn't be happening anyway is a bit much, no?

 

[slicecom]

Spending $70 on something that shouldn't be happening anyway is a bit much, no?

Depends how bad you want it I suppose. You could also spend .50 cents on a 3 to 2 prong adapter but its probably not the safest way to fix the problem.

I'm not so sure it SHOULDN'T be happening, it's happened with most computers I've owned, just nowhere near as badly as it does on my iMac. It would be nice if it didn't happen, but its worth it for an awesome computer in my opinion.

 

[Bitwise]

Don't cancel it, but order one of these too:

http://guitars.musiciansfriend.com/product/Ebtech-Hum-X-Hum-Exterminator?sku=150452&src=3WFRWXX&ZYXSEM=0&CAWELAID=26018345

If my theory is correct, plugging your iMac in through that will completely eliminate all noise. That's why I was asking Bitwise if he had tried plugging in just his iMac with a 3 to 2 prong adapter... could confirm my theory.

Yup works like a charm. I just tested it with the iMac and all buzzing is gone. I think I'll be picking up a hum exterminator. I used to have something similar that would probably work just as well, but I can't seem to find it anywhere :\

 

[tomacintosh]

Depends how bad you want it I suppose. You could also spend .50 cents on a 3 to 2 prong adapter but its probably not the safest way to fix the problem.

I'm not so sure it SHOULDN'T be happening, it's happened with most computers I've owned, just nowhere near as badly as it does on my iMac. It would be nice if it didn't happen, but its worth it for an awesome computer in my opinion.

Saying that, yep you are probably right. If I decide to use external speakers with my iMac, chances are I would rather just get one of them adaptors than complain to Apple. The things we do eh

 

[slicecom]

Yup works like a charm. I just tested it with the iMac and all buzzing is gone. I think I'll be picking up a hum exterminator. I used to have something similar that would probably work just as well, but I can't seem to find it anywhere :\

Great! Thanks a lot for the assistance!