Additional information gathered since original post...
At this point I have purchased and have had the opportunity to use 3 new 5th generation AirPort Extreme Base stations (model 1408). Two came from my local Apple retail store and the third was shipped from the on line store. All three emitted exactly the same buzzing/hissing noise during network traffic. I sit about 2 feet from the AEBS in a quiet home office and these sounds are very annoying.
Two Apple tech support reps claimed they never heard of this problem. I directed them to Apple Support Community postings dating back to 2009 that exactly described this issue (even with the 4th generation AEBS). Although these posts were detailed, as far as I could tell they did not state that Apple provided an explanation. My calls to Tech support have been kicked up to systems engineers. I am supposed to get some sort of reply after July 4.
I think others should make Apple aware of this issue (again) if their AEBS routers make the same noises.
I am getting the same thing with the new 5th generation Airport Extreme. Honestly, it sounds like a hard drive. I hear it when I'm downloading a large file. It really sounds like a hard drive spinning up and down.
I put my ear to it. The sounds changes as download speeds change. I watched a download speed change from 500k/sec to 900k/sec and I can hear a difference in the noise coming from the Airport Extreme.
Please post if you hear back from Apple.
Here is today's reply from Apple..
Apple engineers claim they are unaware of the buzzing/hissing sounds emitted from Airport Extreme Base stations (either from the 4th generation or from our new 5th generation 1408 model). In short, they dismiss all the similar complaints posted on this forum in 2009, 2010 through May 2011.
However, the engineers would like to study my AEBS. In return I will be sent a replacement device. The wrinkle here, according to the Apple rep, is that this replacement will be a "refurbished" 5th gen AEBS. And since this 5th gen model went on sale only about 2 weeks ago, it is almost certain that this so-called refurbished device will not have addressed the buzzing/hissing issue.
Thus, the Apple rep suggested it might be best for me to retain my current AEBS. He kindly offered to call me in 2 weeks time. He thought that in the interim they may receive additional, similar complaints from other users.
Finally, my AirPort Extreme was assessed by a very knowledgable "Genius" at my retail store...
He tested my AEBS in a quiet office in the store. He heard the same buzzing/hissing that I (and apparently many others) have noted. He told me that he just purchased the same model 1408 AEBS for his own use. He sits 2 feet from it and he claims it emits no noise. He can't explain why some units (like ours) do. He changed a few settings on my AEBS to no avail. Also he told me to get rid of any potential electrical interference: I disconnected my cordless phone, moved the router and plugged it into a different circuit, and disconnected my wireless printer. No difference. The only device I didn't disable, of course, was my Cable (Time Warner) modem. The Genius then volunteered that his quiet AEBS is connected to a DSL (Verizon) modem. Could different modems elicit difference noises? He didn't know.
Hey Joel711 -
I recently purchased an AEBS (5th gen)... and was starting to wonder if one of my internal drives was on its way out. My AEBS is on top of my tower on my desk... so the buzzing/high pitch squealing is near my ear. I'm glad to hear that it's not just me. Please post the results of your chats with Apple.
I will probably phone into Apple support in the next week to see what they say...
The AirPort Extremes have no moving parts in them. The power supply, containing a transformer is remote from the main unit. This leads me to believe that any buzzing noise that you hear is due to a manufacturing problem where something is not sealed or properly connected to something else. This could be the metal shields around components on the board. I've seen a teardown of an AirPort Extreme (not the new 5th gen model) and think this is the most likely cause. If you're local Apple genius is willing to take a 'noisy' one apart, they should look for cracked or broken seal, solder joint, glue, or other attaching mechanisms to make sure they are intact.
I just got two new 5th-Gen AEBS too. The second one gotten a few weeks after the first one.
BOTH HISS DURING LOAD!
I think if I exchange either one, I'm going to continue getting the hiss.
I don't know if this is just the way Apple built the 5th-Gen units, but from what I see from this thread - it looks like ALL 5th GEN UNITS have this noise.
It is irritating.
I thought the noise was coming from the refrigerator or maybe the AC adapter was bad.
I can hear this noise from 10 feet away. It sounds like some 21st century version of what dial-up modems sounded used to sound like. The noise comes from an intermediate connector that sits between the router and the AC adapter. It's bizarre and hard to fathom that a company like Apple that's so into silent products would put out a product that has this annoying sound.
I took a padded mailer envelope and wrapped it several times around the piece that makes the noise. Now I can't hear it.
I have just bought an AE (5h generation) for a week. From day 1, it also emits buzzing/ticking sound like the external HDD. The same sound comes from the power adapter and the AE itself, especially when i try speedtest.net or download stuff.
I called Apple support and the guy has no idea, he tried to search his database and suggested to bring AE to apple store. I told him that i have googled and many people have the same problem and whether it is the known problem. He could not answer it.
There is no point to ask for a replacement as it might scream louder than the old one.
There are three readily apparent problems with your solution. First, as you mentioned, it is inelegant. Second, it does not really solve the problem at all, it just conceals it. Third, and most important, the AE can get very hot as-is, especially during periods of increased activity. Insulating that heat by wrapping the AE in several layers of plastic could well be detrimental to the unit. I appreciate your creativity, but I don't think that's the solution we're looking for.