In the Pass Labs section there is a thread about human hearing. John Curl was describing his experiment with changing the slope of square-wave 5kHz signal from some 1us to some 5us and the audible effect of it.
I was told about experiments with addition of ultrasound signal, emitted by high-frequency el/ac. converter, to the audio band signal and audibility of this.
I would like to ask following question: what do you think about intermodulations inside human ear?
I was told about experiments with addition of ultrasound signal, emitted by high-frequency el/ac. converter, to the audio band signal and audibility of this.
I would like to ask following question: what do you think about intermodulations inside human ear?
Hi,
It's there ... and used everyday in hospitals and audiology centres as a standard test. It's realetively easy to measure. You cab go to your docter and say ' I want my intermodulation distortion of my ears measured', he will probably go
... but if you tell him you got bad hearing and want a full check-up, you'll probably get your ntermodulation measured too ..
In the Netherlands many (all?) childeren get such a test, even before they can talk because it tells someting about the functioning of the inner ear without using a subjective patients feedback.
Regards,
Thijs
It's there ... and used everyday in hospitals and audiology centres as a standard test. It's realetively easy to measure. You cab go to your docter and say ' I want my intermodulation distortion of my ears measured', he will probably go
... but if you tell him you got bad hearing and want a full check-up, you'll probably get your ntermodulation measured too ..In the Netherlands many (all?) childeren get such a test, even before they can talk because it tells someting about the functioning of the inner ear without using a subjective patients feedback.
Regards,
Thijs
There is no doubt that Human Hearing suffer from Loudness Related Distortion Effects
There are well documented Loudness versus frequency curves available showing these effects being a form of Hearing Distortion in itself
At Very High Sound Levels, sensitivity to subtleties of musical sounds appear to become lost or masked
Examples are "Disco Night Clubs" or overly loud PA Systems at concerts
I feel certain that the Ear can overload, and in the process produce both Harmonic and Intermodulation Distortion, and maybe even Clipping at excessive Sound Levels
Many recent Pop Recordings are devoid of the subtleties that makes listening to recorded music pleasurable
This is likely caused by monitoring at excessive Sound Levels during the recording or mastering processes
In other words, the ears of the Recording Engineer, or Mastering Engineer, or both distorts making the final CD sound like "Crap"
There are well documented Loudness versus frequency curves available showing these effects being a form of Hearing Distortion in itself
At Very High Sound Levels, sensitivity to subtleties of musical sounds appear to become lost or masked
Examples are "Disco Night Clubs" or overly loud PA Systems at concerts
I feel certain that the Ear can overload, and in the process produce both Harmonic and Intermodulation Distortion, and maybe even Clipping at excessive Sound Levels
Many recent Pop Recordings are devoid of the subtleties that makes listening to recorded music pleasurable
This is likely caused by monitoring at excessive Sound Levels during the recording or mastering processes
In other words, the ears of the Recording Engineer, or Mastering Engineer, or both distorts making the final CD sound like "Crap"
mikek said:
Nope. Here are the ubiquitous Fletcher/Munsen, Robson/Dadson equal loudness curves.
An externally hosted image should be here but it was not working when we last tested it.
se
It is doubtfull that the Human Ear has a Flat Frequency Response, but how do you measure it
The Fletcher-Munson Equal Loudness Contour curves suggest that the response is not flat, and the ear has the grearest sensitivity for frequencies between 3 and 4 KHz
Moreover, the sensitivity to frequencies vary with Loudness
Hearing Loss usually manifests itself at the upper frequencies first, usually due to ageing
Sometimes due to Ilness of various types
Don't know too much about this particular subject
Hearing can also be damaged by very loud Industrial Noise Levels, or instantly if you stand too close to something exploding
The Fletcher-Munson Equal Loudness Contour curves suggest that the response is not flat, and the ear has the grearest sensitivity for frequencies between 3 and 4 KHz
Moreover, the sensitivity to frequencies vary with Loudness
Hearing Loss usually manifests itself at the upper frequencies first, usually due to ageing
Sometimes due to Ilness of various types
Don't know too much about this particular subject
Hearing can also be damaged by very loud Industrial Noise Levels, or instantly if you stand too close to something exploding
Nelson Pass said:
Yes, the brain is a rather amazing interpolator, particuarly in light of all the information that the ears simply throw away and doesn't get past the peripheral nervous system.
But its being an interpolator is also one of its weaknesses because our interpolator is hard-wired to overdetect rather than underdetect which makes subjective perception limited in its usefulness when it comes to establishing objective realities.
So the brain's abilities shouldn't be overestimated either. And I'm not saying you are. But many do and even though we don't know everything, often times those things that we do know are overlooked or ignored completely.
se
I can only go by my own experience and what I've heard (no pun intended).
Firstly, I have some tinnitus, especially a tone at 6K. As a result, when my ears are tested, i can hear above 10k no worries, hell, i can even hear the 16k tone of tv flyback trannies with no problems BUT I effectively have a 25dB peak in the noisefloor at 6k that masks frequencies very close to it if they are below 25dB above my baseline threshold. so far so good (in practice i never notice the 6k tone unless it's quiet or I concentrate on it). The masking effects of one frequency to those nearby may well be similar to intermodulation distortion in their effect. Possibly more so in the next case
Secondly, hearing damage that effects the fine hairs that pick up sound can not only prevent particular tones from being recieved but can also reduce the ability of hearing to filter multiple sounds.
Although my hearing measures ok, I have hassles in an environment with more than a couple of sounds. Making out conversation when alot of other stuff is going on is difficult. This is a common problem. Intermodulation may not be the right word, I'm not sure
Thirdly, I have friends who when at rock concerts have complained about the PA system being distorted but then discovered, upon fitting earplugs, that it was actually their hearing that was being driven beyond its linear region and causing the distortion. The PA itself was largely blameless. Much more a case of clipping than intermodulation.
The upshot is, I believe a number of distortion like behaviours are at work, as well as bandpass loss and noisefloor issues.
And I didn't even go to many discos or rock concerts!
Drew
Firstly, I have some tinnitus, especially a tone at 6K. As a result, when my ears are tested, i can hear above 10k no worries, hell, i can even hear the 16k tone of tv flyback trannies with no problems BUT I effectively have a 25dB peak in the noisefloor at 6k that masks frequencies very close to it if they are below 25dB above my baseline threshold. so far so good (in practice i never notice the 6k tone unless it's quiet or I concentrate on it). The masking effects of one frequency to those nearby may well be similar to intermodulation distortion in their effect. Possibly more so in the next case
Secondly, hearing damage that effects the fine hairs that pick up sound can not only prevent particular tones from being recieved but can also reduce the ability of hearing to filter multiple sounds.
Although my hearing measures ok, I have hassles in an environment with more than a couple of sounds. Making out conversation when alot of other stuff is going on is difficult. This is a common problem. Intermodulation may not be the right word, I'm not sure
Thirdly, I have friends who when at rock concerts have complained about the PA system being distorted but then discovered, upon fitting earplugs, that it was actually their hearing that was being driven beyond its linear region and causing the distortion. The PA itself was largely blameless. Much more a case of clipping than intermodulation.
The upshot is, I believe a number of distortion like behaviours are at work, as well as bandpass loss and noisefloor issues.
And I didn't even go to many discos or rock concerts!
Drew
I can recall friends who went to an Ian Gillian (of famously loud Deep Purple fame) Gig in Adelaide at a small downstairs venue who reported that they saw tatt-covered bikers leaving the gig who were crying because it was too loud.
I just don't understand why they do it. Waste of power, waste of quality, waste of people's hearing.
Drew
I just don't understand why they do it. Waste of power, waste of quality, waste of people's hearing.
Drew
DrewP said:
The problem with rock gigs in small venues is usually down to guitarists with all their amps turned up to full to get their particular tone, and refusing to turn them down, therefore everything else has to be increased in volume to compensate. Also smaller gigs usually have lesser quality PA systems, and in my experience you can actually run louder on a good PA system than a poor one, the distortions of a poorer system causing a higher perceived volume.
Al/ worked on a Gillan gig in the old Marquee Club in London...
Re: tone controls
Hi PMA.
I agree....without tone controls, then an active system, i.e: active cross-overs, individual power amps, with adjustable volume controls, might be the solution....one can then adjust the output from each driver in a system to suit ones taste....what do you think?
PMA said:
Hi PMA.
I agree....without tone controls, then an active system, i.e: active cross-overs, individual power amps, with adjustable volume controls, might be the solution....one can then adjust the output from each driver in a system to suit ones taste....what do you think?
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