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Author Topic: 5D Mark III sensor cleaning noise (squeaks)  (Read 8654 times)

PeterJ

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Re: 5D Mark III sensor cleaning noise (squeaks)
« Reply #15 on: October 28, 2012, 03:02:08 AM »
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.
Not saying you are wrong but are you sure the frequency heard is 37KHz? Just thinking if it's an electronic device it could easily say halve the frequency to make the 'ping' or just detect it and change to an arbtrary frequency that varied in amplitude depending on received amplitude.

I'd also imagine you could get the same effect coupling something that resonated at 37KHz to something else that resonated at a lower frequency without using any electronics.

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Re: 5D Mark III sensor cleaning noise (squeaks)
« Reply #15 on: October 28, 2012, 03:02:08 AM »

AdamJ

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Re: 5D Mark III sensor cleaning noise (squeaks)
« Reply #16 on: October 28, 2012, 09:15:55 AM »
I'm now a bit worried that I've never heard or felt anything from my 7D during sensor cleaning.  :-\

kidcharles

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Re: 5D Mark III sensor cleaning noise (squeaks)
« Reply #17 on: October 28, 2012, 10:52:27 AM »
I can hear mine. I think of it like using Head and Shoulders shampoo and feeling the tingling. I know it's working.

Haha, great analogy. I always loved those commercials, seemed like wonderful nonsense to me. I guess if you poured acid on your head you would also "feel it working" so I'm not sure sensations on your scalp are somehow inherently a good thing.

dlleno

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Re: 5D Mark III sensor cleaning noise (squeaks)
« Reply #18 on: October 30, 2012, 08:42:32 PM »
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.

indeed, given this data,  it is probably sympathetic resonance.  so the sweeps themselves -- is this a single tone sweep or what is the bandwidth of the signal that sweeps through 100KHz to 125KHz?  I take it you were measuring with a wide band audio spectrum analyzer, measuring actual acoustic energy? 

the "vibrating structure" theory aligns well with the 'shifting chirp' experience as well -- the structure exhibits a natural harmonic resonance at two distinct frequencies as the source sweeps through its range.

Quote
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.

fascinating.  If he sound energy demonstrably above 20KHz is experienced and detected by a  human subject of natural abilities and origins, then it is either a sub harmonic, or it is not detected by the auditory nerve via exitation of the eardrum,  which is of course the basis of the "20Hz - 20 KHz" range of human hearing.  Conduction via bone structures is an entirely different mode of detection, which could include sub-harmonic exitation of those bone structures or even the eardrum itself,  which in this case would easily fall within the auditory range anyway.  Also -- sub or supersonic energy can easily be detected, or "felt" even when it is not heard tonally, especially if one's skull is subjected to such a direct mechanical assult :D

Incidently -- on the other end of the sonic spectrum, the lowest fundamental frequency of the largest pipe organ is 8 Hz, which is present on only a few organs in the world.  Such a pipe is there not because anyone can hear it,  but because they can feel it. 

now then, everyone go out and hold your 5D3 up to your skull during the cleaning routine and tell us what you hear!

Mt Spokane Photography

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Re: 5D Mark III sensor cleaning noise (squeaks)
« Reply #19 on: October 30, 2012, 09:30:56 PM »
People can generally not hear ultrasonic tones, but they can dectect pulse trains at much higher than ultrasonic frequencies.  They sound like a chirp.
 
http://grouper.ieee.org/groups/scc28/sc4/Human%20Perception%20FINAL.pdf

PeterJ

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Re: 5D Mark III sensor cleaning noise (squeaks)
« Reply #20 on: October 31, 2012, 07:26:21 AM »
People can generally not hear ultrasonic tones, but they can dectect pulse trains at much higher than ultrasonic frequencies.  They sound like a chirp.
 
http://grouper.ieee.org/groups/scc28/sc4/Human%20Perception%20FINAL.pdf
Hey that was an interesting read ;D. Makes a lot of sense and also made me wonder if some resonant effects also occur in the body, it reminded me of this Russian spying device called "The Thing":

http://en.wikipedia.org/wiki/Thing_%28listening_device%29

Pyrenees

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Re: 5D Mark III sensor cleaning noise (squeaks)
« Reply #21 on: October 31, 2012, 08:55:44 AM »
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!

This is the kind of statement that, if made at high school, would lead to a serious beating. At least, at the high school that I attended  :(

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Re: 5D Mark III sensor cleaning noise (squeaks)
« Reply #21 on: October 31, 2012, 08:55:44 AM »

cptobvious

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Re: 5D Mark III sensor cleaning noise (squeaks)
« Reply #22 on: October 31, 2012, 09:57:24 AM »
I've owned three 60D bodies and one of them had the sensor cleaning squeak and the other two didn't.  I don't think it's a matter of sensitivity to high frequency noise (the suggestion comes up every time this topic comes up) as my hearing range is tested in the normal range.  I think it's manufacturing variances.

EYEONE

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Re: 5D Mark III sensor cleaning noise (squeaks)
« Reply #23 on: October 31, 2012, 10:15:41 AM »
I've been able to hear my XSi, 7D and my 5D Mark III. My wife can hear them too but it seems some people can't. It actually caused some concern when I first got the XSi years ago. I thought it was broken and the internet had very different opinions on it. The people that couldn't here it said it was broken, and others said it was fine. It was pretty funny actually.
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samthefish

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Re: 5D Mark III sensor cleaning noise (squeaks)
« Reply #24 on: October 31, 2012, 10:55:09 AM »
It's the mouse that does the cleaning complaining.
5D MK III, 7D, 24-105  4.0L, 70-200 2.8 IS II, 100 2.8L Macro, 17-55 2.8, Tamron 10-22

rpt

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Re: 5D Mark III sensor cleaning noise (squeaks)
« Reply #25 on: October 31, 2012, 11:20:30 AM »
It's the mouse that does the cleaning complaining.
Hey! Not fair! My camera is missing the mouse! I wonder if I can return it?

dlleno

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Re: 5D Mark III sensor cleaning noise (squeaks)
« Reply #26 on: October 31, 2012, 01:17:02 PM »
People can generally not hear ultrasonic tones, but they can dectect pulse trains at much higher than ultrasonic frequencies.  They sound like a chirp.
 
http://grouper.ieee.org/groups/scc28/sc4/Human%20Perception%20FINAL.pdf

This is a fascinating study, but it is not about detecting ultrasonic tones and doesn't really apply to the subject of ultrasonic hearing.  The study is about human sensitivity to and detection of pulsed radio frequency energy, an energy which consists of oscillating electric and magnetic fields that travel in free (empty) space without air.  This is the energy that, for example  lives in the Amateur radio bands, well above the FM broadcast band for example,  and well into the microwave region.  This is the type of energy that eminates from Television brodcast antennas, cell phone towers, cordless phones, your laptop's WiFi system, and microwave repeaters.  The study is not about ultrasonic "tones" and it is not about acoustic energy.

Acoustic energy (sound) consists of mechanical pressure waves and cannot be transmitted without a medium (such as air or water).  This type of mechanical energy requires an energy source of mechanical origin -- something, like a speaker cone, clapping hands, or Placido Domingo's vocal chords, has to move the air.   The energy used to clean the sensor is acoustic in nature -- this energy is vibrating the bejeebers out of somethign (the sensor) to shake dust loose.  In this sense, we can think of the sensor as a really high frequency tweeter that no one can hear.  In any case,  if the acoustic energy emitted by the camera  is within the set of frequencies to which your ears are sensitive, you will hear something but it won't be the 100Khz cleaning frequency itself.    The question is -- how can a sensor cleaning device operating at six times the upper threshhold of human hearing result in an audible sound? 

by far the best insight into what actually happens in sensor cleaning has been provided by TAF .  Very nice info sir!  TAF showed that the fundamental acoustic energy of the cleaning routine sweeps from 100KHz to 125HKz and back.  there is no way that any human being of natural orgins and abilities can hear this. The acoustic pressure waves reaching the ear just do not produce any response from the eardrum. no way.

of course, if you blast your head with a tremendous high-energy assult of air pressure waves at 100KHz, something is bound to happen internally (to your body)  that can be detected.  but this is not what is happening with the tiny little speaker we know as the sensor cleaning routine.  its a tiny little tweeter producing a very small amount of acoustic energy at frequencies that no one can hear.   

what is far more likely, as TAF has rightly pointed out, is that there is some sympathetic or natural mechanical resonance that occurs within the camera structure itself -- much like the vibrations you hear from your dashboard when driving on certain roads...  The structures themselves are responding at some subharmonic (a sub multiple of the 100KHz fundamental) that is within the range of human hearing.  Note that if this sub-harmonic were present naturally in the sensor cleaning function itself you would hear a high-pitched tone that would sweep up and then back down, perhaps at the 7th or even 8th subharmonic (something between 12Khz and 18 KHz) The fact that no one has reported hearing a smooth frequency sweep is clear evidence to me that TAF is right --  there are fixed frequency mechanical resonances in the camera that will respond, some more than others, when the cleaning "sweep" reaches the right point in its sweep.  Note that if there are two or more natural structural resonances within the camera, then you will hear two or more distinct tones or perhaps they will sound like chirps.  in any case, you are not hearing the sensor cleaning function, you are hearing an artifact or side-effect of it.

what is clear to me , based on the above, is that  (1) there is  a very wide variation from camera to camera structural resonances, and owner to owner hearing abilities,  with respect to what is actually heard during the cleaning routine, and (2) human hearing cannot possibly be used to measure the presence of or effectiveness of the cleaning routine because the cleaning routine itself cannot be heard!. If you hear something, then your ears are sensitive to whatever frequencies your camera's internal structures are vibrating at.  Thats about it :D .  Moreover, when you compare your audible results with someone else, then you are not comparing your respective cleaning systems, you are comparing your own hearing sensitivies and the natural structural resonances present in your respective camera bodies :D

Mt Spokane Photography

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Re: 5D Mark III sensor cleaning noise (squeaks)
« Reply #27 on: October 31, 2012, 01:57:40 PM »
People can generally not hear ultrasonic tones, but they can dectect pulse trains at much higher than ultrasonic frequencies.  They sound like a chirp.
 
http://grouper.ieee.org/groups/scc28/sc4/Human%20Perception%20FINAL.pdf

This is a fascinating study, but it is not about detecting ultrasonic tones and doesn't really apply to the subject of ultrasonic hearing.  The study is about human sensitivity to and detection of pulsed radio frequency energy, an energy which consists of oscillating electric and magnetic fields that travel in free (empty) space without air.  This is the energy that, for example  lives in the Amateur radio bands, well above the FM broadcast band for example,  and well into the microwave region.  This is the type of energy that eminates from Television brodcast antennas, cell phone towers, cordless phones, your laptop's WiFi system, and microwave repeaters.  The study is not about ultrasonic "tones" and it is not about acoustic energy.


what is clear to me , based on the above, is that  (1) there is  a very wide variation from camera to camera structural resonances, and owner to owner hearing abilities,  with respect to what is actually heard during the cleaning routine, and (2) human hearing cannot possibly be used to measure the presence of or effectiveness of the cleaning routine because the cleaning routine itself cannot be heard!. If you hear something, then your ears are sensitive to whatever frequencies your camera's internal structures are vibrating at.  Thats about it :D .  Moreover, when you compare your audible results with someone else, then you are not comparing your respective cleaning systems, you are comparing your own hearing sensitivies and the natural structural resonances present in your respective camera bodies :D
No argument here, I was just pointing out that there is still lots of  things that we do not understand about hearing.  We do not even understand how bone conduction allows some people to hear ultrasonics, just conflicting theories that may or may not be correct.  I tend to believe the theory about bypassing the eardrum and directly stimulating the cochlea makes sense, since many animals actively hear and use ultrasonic sounds.  Others believe that directly stimulating the brain is making it happen, and of course, it could be harmonics being generated in the bone structure that vary from person to person.
Its almost certainly the pizzoelectric ultrasonic driver that excites the sensor generates many harmonics that some can hear.
 

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Re: 5D Mark III sensor cleaning noise (squeaks)
« Reply #27 on: October 31, 2012, 01:57:40 PM »

dlleno

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Re: 5D Mark III sensor cleaning noise (squeaks)
« Reply #28 on: October 31, 2012, 02:32:57 PM »
definately lots we don't know about the abiity of humans to perceive or detect external stimulii of various sorts (especially at high energy levels) in ways that are perceived to be 'hearing'.   thats for sure --  total agreement there.  For example, the ability to detect the application of mechanical energy directly to parts of the body (like vibrating the skull at ultrasonic frequencies) is amusing, too.  Imagine the variance among individuals, i.e. size of the head, bone density, etc, etc.  and maybe those with 5D3s can try pressing their cameras bodies against their heads!

The physiology and mechanics of detecing low levels of true acoustic energy transmitted via air ("hearing") is relatively well understood though, and more closely applies to the phenomena of hearing the sensor being cleaned. 


this has been a cool thread, actually, an amusing departure from Dxo scores arguments :D 

Mt Spokane Photography

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Re: 5D Mark III sensor cleaning noise (squeaks)
« Reply #29 on: October 31, 2012, 02:47:31 PM »
definately lots we don't know about the abiity of humans to perceive or detect external stimulii of various sorts (especially at high energy levels) in ways that are perceived to be 'hearing'.   thats for sure --  total agreement there.  For example, the ability to detect the application of mechanical energy directly to parts of the body (like vibrating the skull at ultrasonic frequencies) is amusing, too.  Imagine the variance among individuals, i.e. size of the head, bone density, etc, etc.  and maybe those with 5D3s can try pressing their cameras bodies against their heads!

The physiology and mechanics of detecing low levels of true acoustic energy transmitted via air ("hearing") is relatively well understood though, and more closely applies to the phenomena of hearing the sensor being cleaned. 


this has been a cool thread, actually, an amusing departure from Dxo scores arguments :D
I'd love to be able to once again to hear even 4K hertz with a hearing aid!  My hearing has gone south to the point where a implant is likely to happen.  I've tried all of the hearing aids, including one that shifts high frequency sounds into my hearing range.  It actually works pretty well at allowing me to hear sounds that I could not otherwise hear, even if the pitch is totally wrong.
Its very frustrating to not be able to understand what people are saying, even with the best hearing aids. 
I've looked into the various technologies for implants, bone conduction systems, direct mechanical stimulation of the ear drum, and discussed them with my doctor, who has done a lot of the original research involving many of the alternate methods, they all have drawbacks, and he is happy to discuss pros and cons.  So far, only the implants seem to be pretty much the gold standard, but I keep watching for a breakthru. 
At this point, I do not want to give up what hearing I have, I only have one ear that has any hearing at all, but the time is coming soon when I will be better off with a implant.

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Re: 5D Mark III sensor cleaning noise (squeaks)
« Reply #29 on: October 31, 2012, 02:47:31 PM »