I seem to have bad luck, or Apple has a chronic problem with this aspect of their engineering (noise/interference). Exchanged my 3G for crackling, 4s crackled but I decided to live with it, 6 has a much more tolerable but faint noise during calls. Samsung and Motorola phones I've used did not exhibit this.
I seem to have bad luck, or I'm a troll. Apple has a chronic problem with this aspect of their engineering (noise/interference). Exchanged my 3G for crackling, 4s crackled but I decided to live with it, 6 has a much more tolerable but faint noise during calls. Samsung and Motorola phones I've used did not exhibit this.
The hissing may be from magnetostrsiction in an inductor used in a switching voltage regulator. As CPU current draw changes, the magnetic field in the switching inductor changes as well, and that becomes audible. An error in the manufacture of the inductor, or in its mounting to the PCB, could result in varying degrees of noise. It's difficult to eliminate completely, though it's usually masked by ambient noise. Similarly, capacitors can exhibit some degree of electrostriction, producing noise when subjected to varying voltage. As current draw changes, there will be some small effect on supply voltage, called ripple. That ripple could (though I doubt it) cause filter capacitors to sing. This same physical effect can cause semiconductors to emit noise. If there is sufficient synchronized switching of voltages across a large swatch of silicon, electrostriction could result in audible noise. This sometimes happens in power transistors.
Ripple will also reflect all the way back to the battery. It may then bleed through to the speaker amplifiers via whatever system regulates the battery voltage for use by audio circuits. There may be modes of speaker operation (speakerphone vs. ear) where this is more audible.
And finally, crosstalk between digital circuits and the analog systems could produce speaker noise.
The current reports don't offer enough information to lay blame on any of these theories, but I will say that explanations of CPU heating causing pressurization of the chassis and gas leakage through small openings... don't hold air. The thermal time constants of the phone internals are too long, and there are other reasons to discount such theories.
The iPhone can take heavy loads? I thought the iPhone 7 Plus was only getting Japanese bokeh, not bukaki. That explains why it's now resistant to fluids.
The iPhone can take heavy loads? I thought the iPhone 7 Plus was only getting Japanese bokeh, not bukaki. That explains why it's now resistant to fluids.
The hissing may be from magnetostrsiction in an inductor used in a switching voltage regulator. As CPU current draw changes, the magnetic field in the switching inductor changes as well, and that becomes audible. An error in the manufacture of the inductor, or in its mounting to the PCB, could result in varying degrees of noise. It's difficult to eliminate completely, though it's usually masked by ambient noise. Similarly, capacitors can exhibit some degree of electrostriction, producing noise when subjected to varying voltage. As current draw changes, there will be some small effect on supply voltage, called ripple. That ripple could (though I doubt it) cause filter capacitors to sing. This same physical effect can cause semiconductors to emit noise. If there is sufficient synchronized switching of voltages across a large swatch of silicon, electrostriction could result in audible noise. This sometimes happens in power transistors.
Ripple will also reflect all the way back to the battery. It may then bleed through to the speaker amplifiers via whatever system regulates the battery voltage for use by audio circuits. There may be modes of speaker operation (speakerphone vs. ear) where this is more audible.
And finally, crosstalk between digital circuits and the analog systems could produce speaker noise.
The current reports don't offer enough information to lay blame on any of these theories, but I will say that explanations of CPU heating causing pressurization of the chassis and gas leakage through small openings... don't hold air. The thermal time constants of the phone internals are too long, and there are other reasons to discount such theories.
This phone seems to be able to vary its power usage very quickly, very high to almost nothing in microseconds, since the CPU is so fast. Wonder if that's the case?
I have an iPhone7+ 256GB on order, and I'm especially sensitive to noise (and tend to use my phone at night, etc). If this is as annoying as they say, I'm definitely returning mine.
I have a really nice iPhone6 that doesn't hiss, I'll keep that if need be.
Did I miss somewhere where it said this was on 100% of all phones??
Why exactly would you assume yours will have this problem??
I have an iPhone7+ 256GB on order, and I'm especially sensitive to noise (and tend to use my phone at night, etc). If this is as annoying as they say, I'm definitely returning mine.
I have a really nice iPhone6 that doesn't hiss, I'll keep that if need be.
Poor baby! I'm glad you weren't around in the 50s and 60s. As a kid I remember walking into a television shop and hearing those flyback transformers singing at about 17khz. Not everybody could hear them, just young people and those with sensitive hearing. I guess you wouldn't have been watching much TV back then would you?
I seem to have bad luck, or Apple has a chronic problem with this aspect of their engineering (noise/interference). Exchanged my 3G for crackling, 4s crackled but I decided to live with it, 6 has a much more tolerable but faint noise during calls. Samsung and Motorola phones I've used did not exhibit this.
This phone seems to be able to vary its power usage very quickly, very high to almost nothing in microseconds, since the CPU is so fast. Wonder if that's the case?
That's precisely the case. The power draw of the CPU actually changes with each clock cycle, as varied amounts of the CPU hardware are put to work to do some function. An add instruction will involve fewer transistors than a divide. Main memory accesses will draw more power than cache accesses, and produce more digital noise, because the CPU chip address and data busses will be active during main memory accesses.
Forking a thread to a dormant core will increase power consumption very quickly. The power management logic will also whipsaw CPU/GPU clock speeds around as well as gating clocks to various subsystems and cores. The aggregate of all these variations will cover a very wide range of frequencies, from the subsonic to well beyond the ultrasonic. You are able to detect the subsonic variations in power consumption by feeling the change in iPhone temperature. The thermal mass of the phone prevents all but the lowest frequencies from being detected via heat. You might detect the ultrasonic variations with a good high frequency sound analyzer. And you could probably detect even faster variations in power consumption with a radio frequency spectrum analyzer.
All of an iPhone battery's stored energy is dissipated in one way or another, either purposely or unintentionally. You feel it as heat (unintentional), see it as light (mostly intentional), hear it as sound (mostly intentional), other electronics devices hear it as radio signal (intentional) or radio noise (unintentional), etc.
This phone seems to be able to vary its power usage very quickly, very high to almost nothing in microseconds, since the CPU is so fast. Wonder if that's the case?
That's precisely the case. The power draw of the CPU actually changes with each clock cycle, as varied amounts of the CPU hardware are put to work to do some function. An add instruction will involve fewer transistors than a divide. Main memory accesses will draw more power than cache accesses, and produce more digital noise, because the CPU chip address and data busses will be active during main memory accesses.
Forking a thread to a dormant core will increase power consumption very quickly. The power management logic will also whipsaw CPU/GPU clock speeds around as well as gating clocks to various subsystems and cores. The aggregate of all these variations will cover a very wide range of frequencies, from the subsonic to well beyond the ultrasonic. You are able to detect the subsonic variations in power consumption by feeling the change in iPhone temperature. And you might detect the ultrasonic variations with a good high frequency sound analyzer. And you could probably detect even faster variations in power consumption with a radio frequency spectrum analyzer.
There are also things like charge pump, buck, and boost circuits that switch at high frequencies (anywhere from hundreds of kHz to a few MHz) to provide different voltages to different circuit blocks, leading to the aforementioned electrostriction or magnetostriction effects.
Until the sound can be localized, i.e., ear speaker, lower speaker, speaker port, display panel, rear housing, lightning port earphone speaker, etc., this is all just speculation. There are numerous potential causes, more than a few of which wouldn't be Apple's fault, e.g., a batch of capacitors more prone to singing, or a high impedance via in the circuit board.
This phone seems to be able to vary its power usage very quickly, very high to almost nothing in microseconds, since the CPU is so fast. Wonder if that's the case?
That's precisely the case. The power draw of the CPU actually changes with each clock cycle, as varied amounts of the CPU hardware are put to work to do some function. An add instruction will involve fewer transistors than a divide. Main memory accesses will draw more power than cache accesses, and produce more digital noise, because the CPU chip address and data busses will be active during main memory accesses.
Forking a thread to a dormant core will increase power consumption very quickly. The power management logic will also whipsaw CPU/GPU clock speeds around as well as gating clocks to various subsystems and cores. The aggregate of all these variations will cover a very wide range of frequencies, from the subsonic to well beyond the ultrasonic. You are able to detect the subsonic variations in power consumption by feeling the change in iPhone temperature. And you might detect the ultrasonic variations with a good high frequency sound analyzer. And you could probably detect even faster variations in power consumption with a radio frequency spectrum analyzer.
There are also things like charge pump, buck, and boost circuits that switch at high frequencies (anywhere from hundreds of kHz to a few MHz) to provide different voltages to different circuit blocks, leading to the aforementioned electrostriction or magnetostriction effects.
Until the sound can be localized, i.e., ear speaker, lower speaker, speaker port, display panel, rear housing, lightning port earphone speaker, etc., this is all just speculation. There are numerous potential causes, more than a few of which wouldn't be Apple's fault, e.g., a batch of capacitors more prone to singing, or a high impedance via in the circuit board.
It'll be interesting to learn the cause (and prevalence). Remember, Apple is the company that designed cooling fans with blades spaced asymmetrically around the hub to spread the noise spectrum and reduce whine...
B Actually it has nothing to do with iPhone 7. It is iOS 10. Today I was importing photos to Google Photos on iPad Pro 9.7" with iOS 10 and the hiss appeared!!! B
For those thinking it is air escaping, explain to me how much air you think is in the case? The hissing is constant. If its air escaping, eventually all the air that can escape, will and the hiss will stop. In the reports, the hiss doesn't stop until the task is complete.
Air is pulsed in an out of a very tiny hole, like a tiny speaker. If the variation in temp is very high and the volume of air very small, you'll get that. Even under load the CPU is not really active 100% of the time.
Speakers put out a lot of air and they're not moving much either.
Pressing the case should raise the frequency.
To your criticism of my, "Constant," comment, I am referring to the constant sound that does not stop. Did you listen to the recording? If it was air escaping, it would all eventually escape, the sound would stop and you would have to wait for the phone to cool for the air to return.
In order to get the, "Breathing," action you suggest (air moving in and out rapidly), the air inside the phone would need to rise and drop in temp at a super fast rate. Unfortunately, that's not how heat dissipation works in a cell phone. Maybe the space shuttle thermal tiles can cool and heat that fast, but its not likely in an aluminum telephone can.
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Ripple will also reflect all the way back to the battery. It may then bleed through to the speaker amplifiers via whatever system regulates the battery voltage for use by audio circuits. There may be modes of speaker operation (speakerphone vs. ear) where this is more audible.
And finally, crosstalk between digital circuits and the analog systems could produce speaker noise.
The current reports don't offer enough information to lay blame on any of these theories, but I will say that explanations of CPU heating causing pressurization of the chassis and gas leakage through small openings... don't hold air. The thermal time constants of the phone internals are too long, and there are other reasons to discount such theories.
Why exactly would you assume yours will have this problem??
#illneverunderstandsomepeople
Forking a thread to a dormant core will increase power consumption very quickly. The power management logic will also whipsaw CPU/GPU clock speeds around as well as gating clocks to various subsystems and cores. The aggregate of all these variations will cover a very wide range of frequencies, from the subsonic to well beyond the ultrasonic. You are able to detect the subsonic variations in power consumption by feeling the change in iPhone temperature. The thermal mass of the phone prevents all but the lowest frequencies from being detected via heat. You might detect the ultrasonic variations with a good high frequency sound analyzer. And you could probably detect even faster variations in power consumption with a radio frequency spectrum analyzer.
All of an iPhone battery's stored energy is dissipated in one way or another, either purposely or unintentionally. You feel it as heat (unintentional), see it as light (mostly intentional), hear it as sound (mostly intentional), other electronics devices hear it as radio signal (intentional) or radio noise (unintentional), etc.
Until the sound can be localized, i.e., ear speaker, lower speaker, speaker port, display panel, rear housing, lightning port earphone speaker, etc., this is all just speculation. There are numerous potential causes, more than a few of which wouldn't be Apple's fault, e.g., a batch of capacitors more prone to singing, or a high impedance via in the circuit board.
Stay in school kids or you too will be spouting nonsense like this.
if anything, it would need a higher internal pressure than the highest pressure expected from outside. Gaskets and strong glue is what it takes.
http://appleinsider.com/articles/12/12/20/patent-filings-detail-retina-macbook-pros-quiet-asymmetric-fans
http://www.imore.com/no-hiss-buzz-not-unique-not-iphone-7-problem?utm_medium=slider&utm_campaign=navigation&utm_source=im
It is iOS 10. Today I was importing photos to Google Photos on iPad Pro 9.7" with iOS 10 and the hiss appeared!!! B
In order to get the, "Breathing," action you suggest (air moving in and out rapidly), the air inside the phone would need to rise and drop in temp at a super fast rate. Unfortunately, that's not how heat dissipation works in a cell phone. Maybe the space shuttle thermal tiles can cool and heat that fast, but its not likely in an aluminum telephone can.