5D Mark III sensor cleaning noise (squeaks)

[ddashti]

When powering on one 5D Mark III, during sensor cleaning, a very noticeable squeaky noise (3-4 squeaks) is produced. It can be heard from around 0.5m away (~1.6 feet).
When turning it off, on the other hand, you can't really hear it (only an occasional squeak).
This has only happened recently.

How bad is this (if bad at all)? And does this need attention?

[Mt Spokane Photography]

The cleaning system uses ultrasonics.  Some people may have good hearing in the ultrasonic range that could be what is happening.
 

[Waterdonkey]

I hear mine.  Three small quiet almost more of a chirp like from a baby chick thats lost its voice... Ceep, ceep, ceep.

[kbmelb]

I can hear mine. I think of it like using Head and Shoulders shampoo and feeling the tingling. I know it's working.

[dlleno]

I doubt that the fundamental or primary ultrasonics are audible to any human, -- unless the distribution of cleaning frequencies is really that broad and some statistically small number of bodies do produce audibles (doubtful).   what seems more likely is some subharmonic resonance or other secondary artifact.  wouldn't hurt to ask Canon about it but I suspect its no issue. If you're really feeling anal you could experiment to see if what you are hearing is a mechanical artifact  -- for example you could take out the memory card(s) just to see if that has any effect and you could  plug stuff into the various electrical connectors while running the cleaning routine to see if this has any noise damping effect. 

[Ryan708]

my 60d has always done that, it makes a high-low sound 2x.

[rpt]

There you go! A whole lot of vampires on this thread! 

[Ryan708]

i can also tell if a CRT monitor or TV is on in a room before seeing it even with the volume off, and the ultrasonic cleaners in jewelry stores drive me nuts. Good thing everything is flat-screen now, no high frequencies I can hear with those!

[thebowtie]

I wonder how you folks go when you stand near people operating hair dryers or power tools - the high-frequency harmonics must drive you nuts!

[dlleno]

just to get anal about this...I'm not aware of any convincing evidence that any human can hear into the ultrasonic region, which of course is why they call it ultrasonic.  Not many of us, save perhaps young girls, can hear above 18K, and the world above 20K is just not audible to anyone of normal orgins .  Males above 20-ish and above rarely hear above 18K.

Frequencies in near ultra-sonic region are not usually identified as having a pitch either -- energy in this range contributes to tonal character and timre via harmonics but typically not pitch.  Thus the report of an audible chirp that changes pitch is clear evidence to me that this not at all ultrasonic energy detected by extraordinarily gifted hearing ability --it is sonic energy in the ordinary audible range. 

Baring some spurious mechanical resonance within the camera itself  there are only two possibilities:

1.  intermodulation distortion -- the combination of two or more frequencies above 20K, producing sum and difference frequencies, can result in sonic artifacts that can be heard (Otherwise, audiophiles and would not care about filtering energy above 20K).   For example, if the mechanical nuances of the sensor and the  ultrasonic mechanism that drives it were to produce  two tones at 40K and 25K (both inaudible), then the combination would produce an artifact at 15K which would be audible.  I suspect the spectral components of the actual sensor cleaning energy is quite broad (not just one frequency), not to mention dynamic, so this is entirely possible.

2.  The Canon system produces energy directly in the audible region.  I find this unlikely

[PeterJ]

When powering on one 5D Mark III, during sensor cleaning, a very noticeable squeaky noise

It's a good feature, how else would your sensor end up squeaky clean?

[insanitybeard]

My 7D has always made the squeak on startup and shutdown, which I have always assumed was the normal operation of the sensor cleaning system!

[sanj]

When powering on one 5D Mark III, during sensor cleaning, a very noticeable squeaky noise

It's a good feature, how else would your sensor end up squeaky clean?

[ddashti]

I appreciate everyone's help with the issue, as I can now use the Mark III without worrying about startup.
And although it was more than what I was asking for, thanks to dlleno for the in-depth information about ultrasonics. 

[TAF]

I just took some measurements, and my 5D3 sensor cleaning 'sound' is a series of two smooth frequency sweeps from 100 kHz up to about 125 kHz and back down.

So I would conclude you are hearing some structure in the camera vibrating, and not the actual signal.

The USM frequency is 30 kHz (and it is loud enough for the 2nd and 3rd harmonics to show up quite clearly), which is unfortunately right in the middle of house cats (and dogs) hearing range.  Which explains why it can be difficult to get good candid shots of our little furry friends sleeping; the lens focusing is very loud and distinct (to them).  This is why I am liking my short 40 so much, as it has no ultrasonic emissions.

I wonder if some of the better shots of lions we see in Canon's literature exist because the lion looked up at the sound of the camera lens focusing?

As an aside, although very few people can hear much beyond 20 kHz in free space, almost everyone can hear to ~40 kHz if the sound is directly coupled to their head ie: via bone conduction.  Dukane makes acoustic devices used to find the 'black boxes' from crashed aircraft underwater that ping at 37 kHz, and if one is held behind the ear, I've never met anyone who couldn't hear it loud and painfully clearly.  And it isn't just the pop of the pulse, you 'hear' the tone.