Unintended Aural Consequences of MP3 Compression

zenst writes "A rather interesting read about possible damage to your hearing due to the way most audio compression techneques work. They mainly work by presenting a signal that the brain perceives to be the same as the original and it is this assumption that could effect our hearing and the way we hear."

Comments

This is pure idiocy...

[Insanity]

Scroll to the bottom and you'll find that this is written by "CYBERYOGI Christian Oliver(=CO=) Windler, (teachmaster of LOGOLOGIE - the first cyberage-religion!)."

This looks like one of many crackpot "religions" based on a few scientific terms and some mystical psychobabble. These are people that believe microwave radiation or EMF from power lines slowly poisons your soul, the world is coming to an end becuase of evil american weather control machines, the aliens have visited us from dimension Z, the ancient Mayan calendar is the key to all knowledge, astrology is a real and important force in our lives, and so forth.

Mix varying amounts of scientific-sounding nonsense, mysticism with references to eastern religions, profound realizations about the nature of space and time, and maybe a few terms like "asymptotically" to really fill the minds of morons with awe and fear, and you have yourself a religion, or more appropriately, a cult.

Other research from the author -- Pink is Evil

[swillden]

From the author's web page:

Warning: Pink can be dangerous for health! about the stress generating, sick making and learn- hindering effect of long exposure to pink in the viewfield

I sure am glad someone is finally focusing on these severe health risks! Where are the Surgeon General's warnings about the risks inherent in MP3s and the color Pink? Why isn't CNN covering this?

I mean, it's obvious that pink must be bad for you -- just look at the grammar in the abstract. The author is obviously a severe sufferer of pinkitis, poor man.

Analogy to vision..

[robbo]

Yes, there's something strange about this article.. it starts off with some interesting stuff, and then some reasonable speculation, and then degrades into some pseudo-religious political rant about DRM and the music industry.

As I read this I couldn't help but thing about RGB displays. The visual world is populated by a wide spectrum of photons of different frequencies, but due to our anatomy, our sensitivity peaks at three wavelengths, approximately red, green and blue. The entire color TV and video industry exploits this fact and achieves huge amounts of compression by transmitting three signals at these peak wavelengths. While I recognize that there are some certain mechanical elements in hearing, it seems to me that if this guy's arguments are sound, then we would have observed similar effects from watching TV-- that the absence of unperceived wavelengths would cause damage. Of course we all recognize that TV's bad for your health, but I don't think it causes the kind of damage he's alluding to.

Its not as crazy as it sounds

[goombah99]

The guy's thesis is VERY speculative. Still it raises some interesting points.

the nerves in your ear and all the low-level neural processing of sound will fire in response to the gaps, watermarks or subliminal signals in the music stream. It is only the brain that filters these out. But is the brain unaware of the signals?

it's long been known that humans perceive sounds they dont actually hear in the sense that their brain registers it. Ancient church organs have sub sonic and ultra-sonic pipes in them for the purpose of stimulating emotional responses in the audience. It's well known from many pyschological studies that slight , consciously imperceptible, delays introduced into telephone conversation response times causes people to think the person they are talking to is angry.As a kid I could always hear the flyback transformers in TVs and video screen. I could not tell you what the sound sounded like--it was not a high pitch. it was no pitch at all. But I could tell it was present.

The thesis that spectral drop-outs could somehow disrupt neural feedback circuits is an interesting one. Certainly most human made electronic circuits dont handle delta-function responses well: that is the phase lag in any feasible feedback circuit puts an upper limit on the fidelity of the response. Thus the idea that the neural feedback that nulls the unwanted off-pitch sympathetic vibrations in the ear following a loud signal could be disrupted if the waveform was not continous after the loud noise is a valid one. Would this lead to false retraining of the neural net and thus tinitiitus? doubtful. But interesting as an example of an unintended consequence no one thought of before.

Don't RTFA

[bobdotorg]

Well, OK, I'll admit, it was an interesting read for me (an ex biologist / scientist). But for the masses, you can either RTFA, or the following summary:

MP3's and other lossy compression (loss of quality through compression) methods change the distribution of frequencies along the sound spectrum, and maybe, just maybe, because nobody has proven otherwise, it might be the case that this can possibly have permanent effects on one's hearing. Maybe. Possibly. We dont really know. Neither do you. Or so we might think. Maybe. Oh yeah - here are a bunch of pictures from a biology textbook that look really cool, but are only connected to our speculation in a weak tangential unscientific way. Maybe.

. I haven't heard so many maybe's and 'might be the case' equivalents since the last 'In Search Of' marathon. And the article didn't even have Spock. .

Re:Tinnitus

[Tim Browse]

It is entirely possible that our eyes require very similar forms of calibration, but that we have not even theorized the existence(sp?) of such a problem b/c we don't spend nearly as much time watching lossily encoded images as we spend listening to lossily encoded sounds.

Interestingly, consider this (lifted from here but you can find it mentioned in many places via Google):

Another example of the brain coming up with better algorithms for doing things, thus showing that many basic brain functions are not hard-wired, involves the use of prism lenses. In an experiment, people are made to wear, for long periods of time, lenses that cause their field of vision to be turned upside down. After a while, the person reports that things have become right side up again. Then, taking off the glasses makes everything upside down. It seems that even this basic fact of how we perceive what is around us is not hard-wired into the brain. Maybe we see right side up because it simplifies the calculations that we need to make in order to perform everyday tasks. Seeing upside down is actually the default, in a certain sense, because the lenses in our eyes turn the received light into an upside down image on our retina. It is the brain that causes the perceived objects to be right side up. The evidence that even this is not hard-wired into the brain is rather interesting, as it indicates that everyone's brain independently and without our conscious knowledge comes to the decision that seeing right side up is the most efficient way to allow performance of daily tasks.

Fun eh? Makes you think. Possibly calibration of the ears works in a similar way. Presumably if the 'lossy' audio ever became a problem (this is assuming you don't speak to anyone, or make/hear any natural noise for most of the day, of course) then you'd just listen to 'normal' sounds. That's what calibration is, after all.

By the way, out of interest, here's another interesting write-up about the experiment being done in Japan. I'm curious to see it was done 'recently', as I remember this experiment being mentioned on TV about 15-20 years ago*.

Tim

* Johnny Ball's 'Think of a Number' for you UK geeks :)