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Hearing damage potential from metal dome tweeters?

ElNino

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I'm curious if anyone is aware of any research on possible hearing damage caused by the resonant peak of some metal dome tweeters or metal cone fullranges?

This isn't going to be a concern with many of the better speakers we discuss here that keep the resonant peaks fairly well-controlled, but for consumer and automotive speakers there are still often ferocious resonant peaks at the end of the audible range.

For example, I was looking at the SB Acoustics 2.5" fullrange (SB65WBAC25-4) for a possible car audio application yesterday. This is not a low-quality driver by any means, but it has a +15dB resonant peak at 20kHz (compared to its SPL at 1kHz). So when used as intended (fullrange), even at a modest music listening level of 85dB, it's consistently generating 100dB of content at 20kHz.

Does anyone know of any research regarding whether that has the potential to cause hearing damage? Obviously off-axis it seems like it should be fine, but for desktop computer speakers or some car audio applications, those drivers might be aimed directly at one's ears.

I'm mostly concerned about the potential effect on kids, as I'm too old to directly hear that 20kHz peak any more. It worries me that I may think the SPL is fine, but may be exposing others to hazardous sound levels.
 
So when used as intended (fullrange), even at a modest music listening level of 85dB, it's consistently generating 100dB of content at 20kHz.
When listening to music with an average of 85 dB, any 20 kHz sound will not be 85 dB. Rather is 40 to 60 dB down from there.
 
Too much SPL over time will damage hearing. Period. The cause of the sound doesn’t matter.

Any well designed speaker will likely be using one of a few possible techniques to make any breakup modes or other resonances inaudible. Thus shouldn’t even be a concern.
 
When listening to music with an average of 85 dB, any 20 kHz sound will not be 85 dB. Rather is 40 to 60 dB down from there.
Exactly. 85dB at 20kHz would drill a hole through your ear drums.
 
... I was looking at the SB Acoustics 2.5" fullrange ... it has a +15dB resonant peak at 20kHz (compared to its SPL at 1kHz). So when used as intended (fullrange), even at a modest music listening level of 85dB, it's consistently generating 100dB of content at 20kHz.
A test sweep of equal input power across the frequency spectrum might excite the resonance, but in practice no program material will have enough energy at 20kHz to cause a problem. Almost all commercial program is silent there. Nothing to worry about.
 
When listening to music with an average of 85 dB, any 20 kHz sound will not be 85 dB. Rather is 40 to 60 dB down from there.
This is a good point, thanks.

With musical selections that skew towards white noise (e.g., Merzbow or anything heavily clipped), would there potentially be a concern?
 
This is a good point, thanks.

With musical selections that skew towards white noise (e.g., Merzbow or anything heavily clipped), would there potentially be a concern?
In general it’s not any specific frequency range that causes harm to our ears. It’s the overall max SPL at our ears over time that causes hearing loss and ringing. There are tones of graphs and tables about sound SPL exposure. Here is one example from OSHA.

1669823459774.png
 
I'm curious if anyone is aware of any research on possible hearing damage caused by the resonant peak of some metal dome tweeters or metal cone fullranges?

This isn't going to be a concern with many of the better speakers we discuss here that keep the resonant peaks fairly well-controlled, but for consumer and automotive speakers there are still often ferocious resonant peaks at the end of the audible range.

For example, I was looking at the SB Acoustics 2.5" fullrange (SB65WBAC25-4) for a possible car audio application yesterday. This is not a low-quality driver by any means, but it has a +15dB resonant peak at 20kHz (compared to its SPL at 1kHz). So when used as intended (fullrange), even at a modest music listening level of 85dB, it's consistently generating 100dB of content at 20kHz.

Does anyone know of any research regarding whether that has the potential to cause hearing damage? Obviously off-axis it seems like it should be fine, but for desktop computer speakers or some car audio applications, those drivers might be aimed directly at one's ears.

I'm mostly concerned about the potential effect on kids, as I'm too old to directly hear that 20kHz peak any more. It worries me that I may think the SPL is fine, but may be exposing others to hazardous sound levels.
Are all metal dome tweeters prone to that kind of resonance issue?
 
Exactly. 85dB at 20kHz would drill a hole through your ear drums.
There must be signal at 20kHz though and what material has that?
 
wasn't FM carrier frequency 19khz, so I doubt music from the radio has much in the way of frequencies up there.

With musical selections that skew towards white noise (e.g., Merzbow or anything heavily clipped), would there potentially be a concern?
Yes, it would be a concern as to why you would listen to stuff like that while driving o_O One needs to pay attention to the road.
 
wasn't FM carrier frequency 19khz, so I doubt music from the radio has much in the way of frequencies up there.
Yes, hence the stereo FM bandwidth is limited to 15kHz.
 
And the 19kHz should have been filtered out by a notch filter in the audio path for stereo tuners.
Not so with cheaper (portable radios) though.
 
In the good ol' days, tape recorders used to have switchable "MPX filters" to avoid the generation of audible artifacts (birdies) produced by the bias oscillator beating against the pilot signal (and, presumably, maybe some of the higher frequency manifestations) of the compatible MPX stereo system. :)

Gratuitous analog aside: To me -- and not that anyone asked ;) -- the FM MPX system is elegance that we just don't see any more in terms of an engineering solution to a problem (mono-FM compatible FM stereo broadcasting, in this case).

1678722545532.png

1678722484750.png

 
In the good ol' days, tape recorders used to have switchable "MPX filters" to avoid the generation of audible artifacts (birdies) produced by the bias oscillator beating against the pilot signal (and, presumably, maybe some of the higher frequency manifestations) of the compatible MPX stereo system. :)

Gratuitous analog aside: To me -- and not that anyone asked ;) -- the FM MPX system is elegance that we just don't see any more in terms of an engineering solution to a problem (mono-FM compatible FM stereo broadcasting, in this case).

View attachment 271396
View attachment 271395
The structure of modern digital broadcasting is good engineering, too.
 
it's consistently generating 100dB of content at 20kHz.
Same as several other comments - not with normal music, which has rather little energy at that frequency. It may happen from time to time but not a concern day-to-day.
 
Why you think so? Or did i gentnt a joke?
The vast majority of the power in music is in the frequencies below about 500Hz.
 
The vast majority of the power in music is in the frequencies below about 500Hz.

Yes but i dont care a shiit about 85dB at 20khz i just dont hear it. Why this should pierce my ears?
 
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