Mac Mini (Late 2012) weird wind noise?

[cdogg007]

I just bought a brand new Mac mini MD388LL/A (core i7 2.3 gHz) for audio recording. I noticed today when setting up each of my audio interfaces that there is a light "windy" noise present. Just to see, I tried restarting the computer and listening with headphones plugged into the Mini's own headphone output (with no interfaces or external sound cards plugged in), and the wind-noise is still there. I did also notice that my mac was completely silent upon first starting up, but once any audio program is opened (Logic, iTunes, etc), the windy sound comes back. Any suggestions?

(I'm gonna try getting a conditioned power strip today, but I have a feeling that may not be it).

 

[cdogg007]

grounded power supply doesn't help

yeah, and grounded power strip didn't do anything, which I'm assuming is because the power supply for the mini is only 2-prong anyway

 

[COrocket]

The mini does have a fan in it, and if it is under heavy CPU load sometimes the fan increases speed to keep the computer cool. I'm not familiar with how much power it takes to run Logic (iTunes doesnt take much) so it could be a possibility.

One thing you can use to check fan speed is iStat Pro widget. 1800 RPM is the baseline and shouldn't be noticeable. From 3000 up to 5500 RPM (max) is where I start to notice a noise.

 

[SoCalReviews]

You are very likely just hearing the system fan speed up. In addition to the other suggestions posted here if you are using USB 3.0 devices make sure you use high quality shielded USB 3.0 cables. Compared to USB 2.0... USB 3.0 cable and devices can be prone to causing radio interference that may result as noise on other cabling and/or devices.

 

[cdogg007]

Well yeah, I checked that it wasn't the fan by listening with headphones connected into another room and it was still there. And at the moment I don't have any USB 3.0 or 2.0 devices plugged in so it wouldn't be an issue of shielding on the cables...

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could it be that the fan is causing interference into the sound card? that'd be the strangest thing ever

 

[SoCalReviews]

I don't think it would be the fan causing the electronic interference noise. Here are some other suggestions... Cell phones can also cause radio interference and static that is picked up by external computer speakers. This use to happen when my older Samsung phone got too close to my Logitech computer speakers and I would hear buzzing and clicking coming from my speakers. Try to determine if it is in fact static radio interference from any external source causing it. Some types of light dimmers that are on the same circuit as your power outlet can cause interference that can be heard through speakers of electronics plugged into that outlet.

Lamp dimmer pollutes the electrical circuit - http://www.youtube.com/watch?v=ManDzw8QrCA

Test the polarity and ground of your power outlet. I use a polarity and ground tester available at most hardware stores. Make sure your circuit is properly grounded. All ground wiring should be wired to the same ground for all the wiring in that house or building. Multiple grounds for the same circuit can cause problems. Improperly grounded house or building wiring can cause ground loop based distortion in electronic equipment that can be heard in the audio circuitry. Do an internet search for more information about audible distortion from ground loops.

Understanding ground loops - http://www.youtube.com/watch?v=4YM1iwC6vhg

Ground loops and hum - http://www.youtube.com/watch?v=GS-6jBk9YPM

Try removing most devices surrounding the Mac Mini and try setting it up in an entirely different room and on a different power breaker circuit with a different power outlet. Check all your signal cabling again by using different wiring. If nothing works to find a solution then the problem very well could be with that particular Mac Mini (hardware or possibly software related) but I would exhaust every other possible explanation first before deciding the Mini is the problem.

 

[MacPC]

Yea, when the mini boots, it does seem to run in full speed for a few seconds, then it stops. Also when under heavy CPU load (using Logic .) The fan will slow increase its speed. Both these appears to be normal. However I have never experienced it interferes with the audio tho.

 

[Schnort]

FWIW, I had my mini connected via USB to a line6 pod xt live, then via 1/8th inch guitar cable to an amp. I had a ground loop until I lifted the ground on the amp.

 

[FrankHahn]

For your information, I had a noise from my Apple Cinema Display, which I originally thought to be from the Mac mini.