AppleColor Composite Monitor IIe is making a "dog whistle" type sound

[Huxley]

Hi everyone!

My big nerd project during Christmas break this year is playing with my Apple IIe Platinum - not counting a few random / "to be expected" glitches, it's all been working well and I'm having a blast. However: my 8yo son has informed me that whenever my  AppleColor Composite Monitor IIe is powered on, he can hear a very high-pitched, very painful sound coming from it. I have some degree of hearing loss in both ears and I'm totally unable to hear any of the sound he's describing, but it's clearly painful enough for him that he's getting annoyed whenever I play on my Apple II. 

A couple folks on Twitter commented that "they always did this" and maybe that's true and it's just been a while and I've forgotten... but if there's any strategy for eliminating (or even reducing) this hum, I'd be really interested. 

Thanks for any tips or suggestions!

Huxley

 

[Johnnya101]

Theyve always done that. Younger kids can hear the high pitched whining from CRTs. I can (Im younger) still. From the size of a CRT that size, a whining is expected (But in a compact? Never!). I used to hear it in my IIgs monitor.

Totally normal.

Theres also the chance its your flyback, but if youre not hearing a louder whine or seeing any issues... its probably the harmless whine described above.

 

[Huxley]

Theyve always done that. Younger kids can hear the high pitched whining from CRTs. I can (Im younger) still. From the size of a CRT that size, a whining is expected (But in a compact? Never!). I used to hear it in my IIgs monitor.

Totally normal.

Theres also the chance its your flyback, but if youre not hearing a louder whine or seeing any issues... its probably the harmless whine described above.

Good info, thanks. My hearing loss occurred when I was a kid, in the years prior to my first exposure to computers, so I guess it's not a big surprise that I'm totally oblivious to this CRT sound-effect! If I wasn't worried about overheating, I'd think about crafting some sort of foam-rubber shell for the CRT to dampen the sound, but that would be a bad idea.... right? 

Or would it.....?

 

[Jinnai]

Heh, I grew up with the sound, even though I'm only in my 20s - we were not rich growing up, and had a 32-inch CRT TV. Since then I've always had CRT monitors for my vintage computers, and most of them make that high pitched whine. For some reason even though my hearing is poor I can still discern it, but my mother absolutely cannot. It's easy to tune it out after several minutes, for me.

 

[LaPorta]

As others said: normal. My wife has always been hearing impaired to some degree. When I fire up a CRT (like the ones in my arcade machine), my young girls and I can hear the whine, while she cannot. The way heading works, the hair cells in your ear that pick up vibration are ordered so those that pick up high frequencies are closest to the outside of the ear (shorter distance = high frequency), while those farther in pick up lower frequencies. As a result, those battered by very loud noises over the years most are the high frequency cells because of their proximity to the incoming sound. This is why high frequency hearing loss usually is first, and why old people have an easier time hearing someone with a low pitch, deep voice, etc.

I went in deep with explanation there, but I figured I’d give you the whole thing!

 

[EvilCapitalist]

...whenever my  AppleColor Composite Monitor IIe is powered on, he can hear a very high-pitched, very painful sound coming from it. I have some degree of hearing loss in both ears and I'm totally unable to hear any of the sound he's describing, but it's clearly painful enough for him that he's getting annoyed whenever I play on my Apple II. 

A couple folks on Twitter commented that "they always did this" and maybe that's true and it's just been a while and I've forgotten... but if there's any strategy for eliminating (or even reducing) this hum, I'd be really interested. 

I'd be concerned if it's loud enough that's it's painful for your son to be near it.  CRTs do make a high pitched whine when they're turned on but in my experience the whine was never loud enough to be painful. 

 

[olePigeon]

Unfortunately I hear the wine, and it causes my ears to ring horribly and gives me a migraine.

I've been investigating swapping out the tube for a 15" LCD TV.  Either that, or just putting hot glue on anything and everything that might vibrate.

 

[Jinnai]

Some whine louder than others, so I do think it would be a good thing if we found a way to reduce the noise. I don't know much about electromagnetic frequency stuff though, all I know is that I've heard the frequency of the horizontal overlaps with the human audible range somehow. 

 

[Gorgonops]

The source of the whine is the flyback transformer and is an inherent side effect of it doing its job. The base frequency of the noise is 15-something Khz, which is why many older people can't hear it; that's basically about where the normal response curve for human beings starts diving sharply downwards. (Some people with fantastic hearing can detect sounds into the low-20s khz but not with any fidelity. For comparison, the highest key on your piano is around 4khz.)

The noise shouldn't normally be loud enough to be "painful", however. The usual culprit for it getting loud is excessive vibration, either from poor mounting/it coming loose from the circuit board, or the transformer itself breaking down internally. Given the age of these monitors it's very probable its simply a result of the various adhesives breaking down. I don't know off the top of my head if there's any product (like hot glue, etc) that would be safe to goop all over the flyback area to damp it down, which would basically be the only solution other than trying to replace it with a better preserved one.

I bought my first LCD (projection) TV set back in 2004 in part because the flyback started whining on the Sony 31" I was using at the time. I was the only one in my "peer group" that could hear it; apparently I'm the rare Gen-X-er that didn't melt their high frequency hearing with a Walkman back in the 80's and 90's. (Or iPod in the 'aughts.) I also remember the noise from monitors when I was a kid, but apparently I was better at tuning it out.

 

[techknight]

Well before we shrug this off as "normal" 

There is normal, and there is excessive. If the core is loose in the flyback transformer, it will vibrate and you will hear fundamentals of the center frequency totally exacerbating the situation. If you pop the cover off, grab an insulated plastic thing somewhere and push on the flyback ferrite core a little bit while it is on, if the ring noise suddenly dampens, thats your issue. 

Lucky me, my hearing has deteriorated to the point I cant hear it anymore unless someone cranks it up on an amplifier, main reason being is my tinnitus has reached down to the 15Khz level. 

 

[Gorgonops]

Well before we shrug this off as "normal" 

Just to be clear, I only say it's normal for there to be a "detectable" high-pitch noise present with most TV-frequency CRT monitors; when I was young at least (maybe not for sure now) I'm pretty sure I'd be able to reliably tell you if a monitor or television set was turned on in an otherwise dead-quiet room no matter how new and perfect the flybacks might be. But, yes, "painfully loud" almost certainly points to a problem. Sure, it's possible the child in question just isn't used to the noise and interprets hearing it at all as "painful", but with a healthy monitor almost any other noise in the house should pretty much drown it out.

When a flyback really goes to heck, as Techknight says, you'll not only get the center frequency, which is on the edge of audible for the lot of the population and may well go unnoticed, you'll get harmonics that should be audible to just about anyone. I've heard dying flybacks in VGA/Multisync monitors that were vibrating enough to make relatively low-pitched growling noises. In something like a VGA monitor the base frequency would be too high for *any* human ear, of course, so if you're hearing the flyback in your iMac or whatever it definitely has at least one foot in the grave.

 

[Scott Baret]

That monitor always made a noise. I remember it distinctly from the one we had outside our first grade classroom. If someone had left it on and the hallway was quiet, you could hear it if you were close enough.

 

[techknight]

I guess everyones hearing tolerances are different. When I was a kid, I could tell if a TV was left on all the way across a room. But it was never really painful. But during those same days, I could never listen to FM stereo either because I could hear that 19K pilot tone. 

Now I am lucky to hear above 14khz before it all blends into my tinnitus. These days I hear the old school "tv flyback running" 24/7. Called Tinnitus. LOL.

 

[PB145B]

These days I hear the old school "tv flyback running" 24/7. Called Tinnitus. LOL.

Hah, same here! Had it ever since I was little. However, I can still hear the flyback sound on some of my CRTs.