Hi,
I just got a new Airport Extreme dual band (Model A1354) and it does make the hissing / buzz noise when there is network activity, not sure if only with wireless or also ethernet.
I made a quick search in google, and it seems that, although most of the times this noises go unnoticed, they are quite usual in some routers (and I assume in other electronic devices even with 'no moving parts'). The cause seems to be a vibrating coil in the DC-DC converter. I found a good explanation in this forum:
http://www.dslreports.com/forum/r22742126-New-WRT54GL-router-makes-faint-hissing -noise-
( Note that it refers to a Linksys router, not apple, but I guess the cause is the same).
It seems that it is normal that these DC-DC coils vibrate, but usually their frequency should be not audible... However, depending on the exact voltage of the external supply and the consumption oscillations due to network traffic, the vibration can get into audible margins...
Take also a look here: http://www.practicallynetworked.com/support/hissing.htm
To sum up, I think this is not an issue to worry much about, but a company like Apple should address this little issue as it can be annoying if you have an acute ear...
Daniel P.
p.s. I tried to answer to other longer threads about the issue but they are archived. If somebody knows how to post there, feel free to copy my reply.
Actually, the noise is pretty annoying, specially when working in the 5Ghz band... I can perfectly hear the hissing from 6 feet away if the room is in silence: that means that if somebody had to sleep in the room, the router cannot be downloading because of the noise it makes. It is not 'loud' but it is very annoying...
I cannot believe Apple quality controls have passed this unnoticed in so many devices... more taking into account that the problem has been reported for months...
I think I will have to try a replacement at Apple!
Can somebody send me a video or two of this? We'll try to debug it. If we can't figure it out, I'll at least write an article about it to try to get it some additional press.
you can contact me at carotids@gmail.com
Here is my video of the sound. You can hear the high pitched really crank up when I do a speed test. http://www.youtube.com/watch?v=lX_Pfkmh8Xk
It is really annoying since it sits right next to me. I've never had another router with this problem.
Carotids, where will you publish such a review?
AIrport Extreme - Very loud buzzing and fizzing noise on Wireless Access
