Speakers make noise when external monitor is connected

Yes, there are many reports of noises in the audio with an external display and external speakers. I think it must be a grounding problem, and if so, an isolating transformer should help. I have one at work and will bring it home to try soon. I'm not hearing the noises with the external speakers but no external display, nor with external display and headphones.

http://www.radioshack.com/product/index.jsp?productId=2062214

louie wrote:

louie wrote:
Yes, there are many reports of noises in the audio with an external display and external speakers. I think it must be a grounding problem, and if so, an isolating transformer should help. I have one at work and will bring it home to try soon. I'm not hearing the noises with the external speakers but no external display, nor with external display and headphones.

http://www.radioshack.com/product/index.jsp?productId=2062214

This does solve the problem for me, at reducing the noises by maybe 99.9%. This indicates to me that a design error exists with the ground paths for the analog audio and the DVI display circuits, since this was not a problem on my G4 Powerbook.

I am currently working with applecare on finding a solution to this problem. (they are going to ask the apple engineering dept. for help) :/.... I hope it doesn't come down to using an isolating transformer. It isn't right that you should need to use extra equipment to do something so basic as to use an external monitor with sound! Apple should be responsible for a flaw like this! I will keep posting updates as I get information from apple.

I'm having the same problem. Same MBP. I've had it for almost a year and just plugged it into my Sony SDM HX93 monitor this week for the first time. I had been using the monitor w/ a G4 AGP that I'm trying to phase out of. I can hear noises from the monitor's speakers when I brush across the trackpad in addition to the always present static. I tried switching to my modded Koss "the plug" earbuds and hear no trackpad static or hiss other than from the recordings.

I've just turned down the treble a bit on the monitor but, it's still there just a bit less.

Anybody else??

ajs, Have you discovered anymore on this?

If the monitor is plugged in with a 3-prong plug, it might be worth trying one of those grey, 3-prong to 2-prong converters. That would break the chassis ground connection between the monitor and earth ground and may eliminate the hum. It's worth trying since the plug is cheap and something you may already have laying around the house.

Louie and B,

I'll give the 3 into 2 ground adapter a try first as I'm sure there's one in the house. It makes sense as I only get these noises w/ the monitor speakers and not with the earbuds.

I never had this issue w/ my G4 powermac plugged into the same power source and monitor.

I'll report back.

Thanks

I got the same problem when I hook up my mbp to my sharp aquos via dvi and with a 3.5mm to 3.5mm cable

So asking applecare about fixing it would not be worth the time??

louie wrote:
Yes, there are many reports of noises in the audio with an external display and external speakers. I think it must be a grounding problem, and if so, an isolating transformer should help. I have one at work and will bring it home to try soon. I'm not hearing the noises with the external speakers but no external display, nor with external display and headphones.

http://www.radioshack.com/product/index.jsp?productId=2062214

This does solve the problem for me, at reducing the noises by maybe 99.9%. This indicates to me that a design error exists with the ground paths for the analog audio and the DVI display circuits, since this was not a problem on my G4 Powerbook. Note that the Radio Shack product comes configured as dual RCA male plugs on both ends, with an adapter to convert one side to 3.5mm stereo mini plug. If you need to go from 3.5mm mini jack to 3.5mm mini plug, you'll need to buy another adapter - I made one.

An audiophile grade equivalent is available from Jensen Transformers, the Iso-Max:
http://www.jensen-transformers.com/ci2rr.html
and there are undoubtably other products. Look for transformer ground loop isolators.

I do not suggest trying a ground adapter on any piece of 3 prong equipment. This can be a lethal safety hazard if the ground is not connected.

Good luck with that. I agree it's not right, but IMO, it would involve cutting and/or rerouting 1 or more ground traces on the circuit board. I really doubt this would be practical for anyone- even Apple - to do on an out of production item. The Radio Shack device is $17USD. Perhaps Apple would give them to people who ask!

Hooked up my MBP to my Viewsonic via VGA and Bose home theater and nosie. Booted via boot camp to Win XP - no noise.

So I doubt it's hardware.

Once again, Apple - it just work, just like iWorks being compatible with Office - but again where I grew up we had an old expression -they **** in your face and tell you it's raining. That's why during my frequent trips to the Apple store I take an umbrella !

Ah, very interesting!

I tried the 3 into 2 conductor ground adapter. The speaker noise is still there on my external monitor speakers. I will go back to NOT using the ground adapter plug.

And yes, it would be nice if Apple could figure this out.

It's annoying. If it grates on me and I have time, I'll do the RadioShack option.

lowcarb wrote:
Hooked up my MBP to my Viewsonic via VGA and Bose home theater and nosie. Booted via boot camp to Win XP - no noise.

I hooked up my tv again to the mbp in vista (via boot camp) and I still got the noise 😟. May be a hard ware issue with this specific computer. No response from applecare yet, though I will send this information along to the support rep.

Unfortunately I've just written started another thread about this very same problem I'm having with my late 2006 MBP.

http://discussions.apple.com/thread.jspa?threadID=1855199&tstart=0

I figured it was ground loop problem so I bought a DI box with switchable ground lift - and it made no difference whatsoever!

I'm also in touch with Applecare so I'll post any answers I get from them. I'm glad I'm not the only one having this problem!

Regards,

Martin

Just to report back...

Applecare suggested I take my laptop into an Apple Store because my fault "may be a hardware problem", but I've decided not to do this as a) I can live with the current solution (see below), b) I've got a lot of work on and can't be doing without the laptop at the mo and c) I'm not sure they can fix it.

The Ground Loop Isolator suggested above by Louie did the trick for me. It's a bit silly that over a grand's worth of computer has this problem in the first place, but thankfully the solution is an inexpensive one.

Thanks to Louie for the suggestion!

Found the problem, I disconnected any (red and white) cables from my receiver to the TV. Now no noise.