Unintended Aural Consequences of MP3 Compression 670
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."
Great, the Record industry get you again (Score:1, Interesting)
Makes sense, but comes off as slightly hysterical (Score:2, Interesting)
Eventually, the paper does acknowledge that this is something to look into, not a reason to ban MP3s (& DVDs, & digital TV, &
Actually it is still unclear whether the consequences of such maladjustments are only temporary
The second to last paragraph is devoted to basically saying that the author is not against MP3s, which is a good idea for reducing the flamebait of this essay. But then the essay ends with the alarming (& rather unbelievable) statement:
But here definitely exists acute research need, therefore I request hereby all politicians and neuroacoustics scientists to be concerned with the danger potential of neuroacoustic data reduction...
Now, I'll agree that MP3s aren't perfect; I'll get "sick" of them every so often (when they sound to feel tinny & empty) & have to listen to some CDs or other media... But I'd have to imagine that the scratches most tapes & records have are more damaging than the acuoustic gaps an MP3 has. I can't comment on OOG because I don't use it; my portable MP3 player can't play them, so it would be inefficient to use them.
However, it is an interesting idea to try filling the gaps via interpolating the surrounding frequencies. I'd be curious if this has been done before, and how it sounds.
Re:This is FUD (Score:3, Interesting)
For more FUD, read the same guy's discussion of why pink [fh-hamburg.de] (yes, the color pink) can hazardous as well.
Or, you might want to try his discussion of conscious computers [fh-hamburg.de]. My favorite quote:
Mmmmmkay.This is pure idiocy... (Score:5, Interesting)
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 [bluehoney.org], or more appropriately, a cult [scientology.com].
Who funded this? (Score:2, Interesting)
"Don't steal music. Or you'll go deaf. Then die."
Other research from the author -- Pink is Evil (Score:5, Interesting)
From the author's web page:
Warning: Pink can be dangerous for health! [fh-hamburg.de] 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.. (Score:5, Interesting)
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.
Re:This is FUD (Score:3, Interesting)
Lossy compression won't damage your ears any more than watching digitally compressed TV (DVD, Digital Satellite or Cable, etc) will damage your eyes.
After a while you might start to accept a lossy picture as being "as good as it ever gets", and the same with lossy audio - you might not be aware of low bitrate compression artifacts if you don't ever listen to an uncompressed source, but it won't damage squat.
Lots of people watch digital TV and are "amazed" by the clarity of the picture after coming from off-air or cable systems. Their expectation of quality goes up. The same will happen when they get HD (if ever). Their standards will go up again.
It could be argued that a CD is "lossy" compression - it's taking analog audio and digitizing it at 44khz/16bit to make a digital representation. Sure it can reproduce frequencies over the normal range of human hearing, but is it as good as the analog audio coming in? Never. That's why 96khz/24bit and higher sampling was introduced, to try and even better represent the original sound.
And tinnius by the way, can be caused by many things... Just take 3 or 4 of the 500mg Asprin tablets and you'll ears will probably be ringing nicely (well known side-effect).
Its not as crazy as it sounds (Score:5, Interesting)
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 (Score:4, Interesting)
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 (Score:5, Interesting)
Interestingly, consider this (lifted from here [rochester.edu] but you can find it mentioned in many places via Google [google.com]):
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 [go.com]. 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 :)
like Mark Levinson (Score:3, Interesting)
It's like this: the ear is able to pull a lot of information out of natural, acoustic sound. There's regular features to such sounds that are distinctly different from plain random noise. The ear can dig into the random noise very deeply to get information out.
What these guys are saying is this: with certain types of distortion, the noise becomes opaque, the information just ain't there when the ear tries to dig for it. Soon it stops trying- or just gets out of practice. It atrophies.
There are a few points that are established (some recently) to support this, though the whole chain of evidence isn't there, and in fact it's a bit alarmist.
(1) Ears do adjust. If your hearing isn't symmetrical, your brain WILL construct a coherent picture from the sound field, despite the ear inputs not matching.
(2) Digital noise floors are NOT the same as natural white noise.
That last helps to support these wilder theories, but nobody that I know of had tested it until recently. I got in an argument on Usenet where I had to establish this. The argument was that dithering and truncation produced a noise floor different from the same signal with exactly equivalent white noise overlaid onto it. Basically, that quantization can be heard as a distinct character to the noise floor.
I had people very huffy about me even arguing this, because their digital audio theory demanded that dithered digital was perfect in every respect, and specifically that it behaved the same as analog noise w.r.t. detail retrieval beneath the noise floor.
I was given matching files- one being signal plus random-amplitude noise, and one being the same thing but quantized to the level of the noise, resulting in a normal TPDF noise floor, entirely uncorrelated. There was a 2 bit and a 4 bit example for me to try, because I was arguing that this difference was obvious at coarse levels, not that I could consistently hear it at 16 bits or something.
I did a computer ABX double-blind test, using both the examples, and got 40 out of 40 trials correct, establishing beyond reasonable doubt that these types of noise DO sound different. It's not even subject to debate anymore- that's what ABX is for- not asserting a negative but proving a positive beyond serious doubt. Dithered noise floors measure a lot like broad-band noise, and they may be uncorrelated, but they are absolutely not the same as simple random-amplitude noise (like you use for the dither signal prior to quantization).
I'm not aware of anyone doing this test before, but now it's been done and the point proved.
I am inclined to agree with the lunatic fringe here that it's the results of these very 'unnatural' processes which cause problems- they damage musical enjoyment, and they're part of why modern music is so commodified and worthless. The only serious mass media formats are prone to these problems. As a result, mass media itself seems less important- a self-destroying process. The sound alone contributes to a lessening of interest.
That said- anyone who had their hearing actually damaged by this effect would have to either live in an anechoic chamber or wear Walkman headphones every waking moment. The world is FULL of acoustic sounds- hell, traffic alone is an acoustic sound quite capable of 'recalibrating' the ear, and any face-to-face human contact often involves sound, which also 'recalibrates' the ear. So the alarmism is entirely foolish. Maybe Mark Levinson lives in an environment entirely free of any outside sound, I don't know :)
Dude is a total crackpot (Score:3, Interesting)
Check out his "biography."
He's a "cyberyogi," a teacher of "logology." Uh.. yeah. From his site:
Logologie is a religion of reason; it is free of devilization and has many things common with Buddhism, but unlike this it includes a much more detailed understanding of the physical interaction between consciousness and the nervous system. Main goal of Logologie is the preservation and development of the human race by enabling it to sovereignous- holistical thinking and the overcoming of causing sufferance, because due to the network of cosmic consciousness everything is connected with everything and sufferance therefore never exists separately.
I am a cyberage-child - born in the year of Pong, and I study software- techniques at the German technical college Fachhochschule Hamburg (which unfortunately consumes the major amount of my time).
I am researcher of neuronomy and consciousness physics. (Neuronomy is the science of the improvement of the usage of brain and nervous system.) I collect historical videogames and homecomputers, I enjoy to build and repair electronic things and I am interested in electronic musics, synthesizer technology and everything that makes unusual (mostly electronic) sounds. I also compose own musics (e.g. like tekkno- trance, meditational musics etc.) and like to write poems and short stories etc. (e.g. SF), paint computer graphics and I am generally very interested in art and philosophy.
Uh.. yeah. Sounds credible to me.
Phexro, your hearing sucks! (Score:2, Interesting)
> I remember when I first started encoding my CDs, I couldn't tell the difference between 128kb CBR MP3s and the CD source.
Actually Phexro, this does not mean your hearing has gotten better, but that it has gotten WORSE.
Your hearing use to be so well tuned that it could compensate for irregularities in 128 encoding, preventing your brain from ever perceiving them. However, now that you've grown accustomed to listening to MP3 audio, your brain's hearing has lost the ability to fill in the gaps as well, because it doesn't remember how.
Rather, your brain is doing its job by noticing the gaps in the signal, and figures this is for a purpose, and turns those gaps into noise for you to
AgV