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Topic: Can MP3 or other lossy codecs... (Read 21661 times) previous topic - next topic
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Can MP3 or other lossy codecs...

Reply #50 –
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Did anyone looked at the history of equal loudness curves? I am wondering about the peak at approx 16kHz. Does TV's horizontal deflection has anything to do with it?

There is no peak at 16 kHz as far as I know. The curve is continuously increasing from about 13 kHz, where the second dip has it's minimum. If this dip is what you're referring to, it has nothing to do with TV. It's because of the length of your ear canal - it works like a 3/4 wave pipe resonator around this frequency.

I leave it as an exercise to calculate the length of your ear canal and check if it's correct. The speed of sound in air is 340 m/s.

Thanks noting it, PAL or NTSC standard, it is the same 15625Hz, to which the ear is more sensitive (dip) than to frequencies a little bit below. I see no reason why evolution would have selected humans, who can locate TVs better just by ear.

Can MP3 or other lossy codecs...

Reply #51 –
I hate that tone very much. It nearly makes me gag.
That's the only reason I use a TV tuner card.

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I see no reason why evolution would have selected humans, who can locate TVs better just by ear.


Well, it may soon happen... who knows.
ruxvilti'a

Can MP3 or other lossy codecs...

Reply #52 –
Thanks Audible! I think that's answered the issue I was hinting at in my paranthetical* remark. I make no claim to understand the biology that is or is not involved in evolutionary change. This ignorance is not due to Kansas state educators**, but due to dropping biology at the age of 13, and not really paying attention before that.

Cheers,
David.

* if that's not a real word, then I've just invented it.
** there are, of course, plenty of scientists (even biologists) who are Christians, and thankfully the Kansas experience is unlikely to be repeated in the UK.

Can MP3 or other lossy codecs...

Reply #53 –
SERIOUS ADVICE:

In the UK we have Health and Safety laws that regulate the maximum volume that films can be played at cinemas.  The limits DO NOT APPLY TO ADVERTS.  This is why the Adverts in some cinemas sound so deafening.  They are frequently well in excess of the safe limits and doing harm to your hearing.

Can MP3 or other lossy codecs...

Reply #54 –
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SERIOUS ADVICE:

In the UK we have Health and Safety laws that regulate the maximum volume that films can be played at cinemas.

Utterly typical UK killjoy type attitude.

The notch filter thingy is interesting though... Although all the under 35's I know can tell a tv's whistle.... but strangely only people with an active interest in 'electronics' (broad broad definition) 

Can MP3 or other lossy codecs...

Reply #55 –
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I'm planning to patent an even better hearing aid: from the outside it looks like an ordinary hearing aid, but it's actually a hollow piece of plastic. I bet people will swear it works great.


HOLLOW?

OMG - the audiophiles will scream bloody murder about the cabinet resonance! 

Can MP3 or other lossy codecs...

Reply #56 –
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SERIOUS ADVICE:

In the UK we have Health and Safety laws that regulate the maximum volume that films can be played at cinemas.  The limits DO NOT APPLY TO ADVERTS.  This is why the Adverts in some cinemas sound so deafening.  They are frequently well in excess of the safe limits and doing harm to your hearing.

?!?!

A link would be useful. What you're saying makes does not match my experience at all, and as far as I know there is no such law.

There may be a law regulating sounds above 120 or 125 or 127dB, and there are certainly laws regulating industrial noise (as with many health risks at work), but there's nothing "sensible" regulating recreational noise exposure - or is there?

FWIW there's nothing "kill joy" about prohibiting 127dB+ (if that regulation exists - I'm guessing) - that's the point at which near instant, irreversable hearing damage starts.

Though I'm sure I've been in quite a few clubs where it's louder than this next to the PA.


Here's a more sensible law: any venue where sound levels exceed those allowed in industry should provide free, discrete, and readily available ear defenders.

Cheers,
David.

Can MP3 or other lossy codecs...

Reply #57 –
Quote
SERIOUS ADVICE:

In the UK we have Health and Safety laws that regulate the maximum volume that films can be played at cinemas.  The limits DO NOT APPLY TO ADVERTS.  This is why the Adverts in some cinemas sound so deafening.  They are frequently well in excess of the safe limits and doing harm to your hearing.

Well, the adverts don't have more sound pressure than the actual movie, it's more likely that it is compressed to have just that effect - to be percieved louder. Same goes for any broacast such as radio and TV where you lessen headroom and average out on peak levels.

You know, if you found the experience unpleasing wathing the movie, all you have to do is complain and you should get your money back. Tell them you felt pain in your ears to give them a scare. I've done that a few times and I've always been compensated.

Can MP3 or other lossy codecs...

Reply #58 –
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There is no need for research. There is simply nothing in compressed music that could be harmful to human ears (other than the volume it's played at   )

Undocumented claim. Please provide proof.

I can actually make the opposite undocumented claim: Lossy music have already caused world-wide brain and ear damage: 90%+ of people worldwide thinks 160 kb mp3 is perfect for listening, whereas I get a headache after listening for a few minutes.


I love this forums sense of humor. You guys are too much.

What about when amplified heavilly? It makes sense that under normal listening conditions there should be no ill-effect. HOWEVER. When you add uniform layers of compression, eq, and amplification to a compressed lossy file, would that not accentuate the middle to upper range that seems to be more present in some lossy files? The most sensitive part of human hearing?

I can tell you from direct personal experience and concurring experience from many other dj's and club sound techs that there is such a "sound" to heavilly amplified mp3s. We play in some of the biggest night clubs in the world, often 3-4 times a week for the past 10 years. So its safe to say there has been plenty of listening done. 

What would amplification,uniform eq and heavy compression add to the scientific picture?

Can MP3 or other lossy codecs...

Reply #59 –
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There is no need for research. There is simply nothing in compressed music that could be harmful to human ears (other than the volume it's played at   )

Undocumented claim. Please provide proof.

I can actually make the opposite undocumented claim: Lossy music have already caused world-wide brain and ear damage: 90%+ of people worldwide thinks 160 kb mp3 is perfect for listening, whereas I get a headache after listening for a few minutes.


I love this forums sense of humor. You guys are too much.

What about when amplified heavilly? It makes sense that under normal listening conditions there should be no ill-effect. HOWEVER. When you add uniform layers of compression, eq, and amplification to a compressed lossy file, would that not accentuate the middle to upper range that seems to be more present in some lossy files? The most sensitive part of human hearing?

I can tell you from direct personal experience and concurring experience from many other dj's and club sound techs that there is such a "sound" to heavilly amplified mp3s. We play in some of the biggest night clubs in the world, often 3-4 times a week for the past 10 years. So its safe to say there has been plenty of listening done. 

What would amplification,uniform eq and heavy compression add to the scientific picture?
[a href="index.php?act=findpost&pid=320421"][{POST_SNAPBACK}][/a]


Since the goal of lossy encoders like lame, vorbis and musepack is that the encoded files should sound good in normal listening conditions, atleast at moderate bitrates, you can't expect that it should work as well in the conditions you describe. Probably the first thing that would harm you would be the loud volume. Annoying artefacts caused by a low quality encoder or a transcoded encode would simply make artefacts more obvious. And EQing that makes masking less effective creates more artefacts.

EDIT: I have some mp3s that sound horrible in normal listening conditions, and I don't even wan't know how bad it could sound in a night club. So the best thing you can do is use a good encoder. But I highly doubt it could cause any physical harm, except mental stress. 

Can MP3 or other lossy codecs...

Reply #60 –
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When you add uniform layers of compression, eq, and amplification to a compressed lossy file, would that not accentuate the middle to upper range that seems to be more present in some lossy files? [a href="index.php?act=findpost&pid=320421"][{POST_SNAPBACK}][/a]


This range is no more present in lossy files than in lossless ones. What does make you think so ?

Can MP3 or other lossy codecs...

Reply #61 –
He may be referring to clipping resulting from the >0dbFS peak values resulting from compression. I guess that could result in a particular "sound", although I find it unlikely. It is also more of a bug in playback than anything else, and any good player is going to do the right thing and attenuate or limit/compress.

Can MP3 or other lossy codecs...

Reply #62 –
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QUOTE(eangolden @ Aug 16 2005, 10:48 AM)
When you add uniform layers of compression, eq, and amplification to a compressed lossy file, would that not accentuate the middle to upper range that seems to be more present in some lossy files?


This range is no more present in lossy files than in lossless ones. What does make you think so ?


I don't want to break rule #8 this soon upon joining the forum (my 2nd post!) however, I can tell you from years of subjective listening in clubs and confirming with others with the same experience. I would love to perform a objective double blind but I don't really know how this could be performed as it is not a listening test but an endurance test.

I have 2 hypothesis that might support this "experiential data" however. These are really a shot in the dark. I am not trying to sound like I know it all.

1. Most club sound systems are still tuned and calibrated with vinyl play back in mind.  Sudden drop offs at 19khz or 19hz are not taken into account. often large amounts of uniform (all frequencies equally boosted) compression and eq are applied. Not too mention a large amount of natural distortion from amps and circuitry on all freq.
this would sound fine if applied to a sound source with all frequencies present. the frequency perception response would be uniform across the spectrum. However if you take away, say everything from 19hz bellow and remove other "indiscernible frequencies"  their overtones
would be missing as well. if overtones are a real, perceivable reality the remaining frequencies would have an abnormally increased presence.

2. not all mp3's are created equal, we can all agree there are really terrible ones most likely being played in clubs right now. Although a perfectly encoded LAME mp3 may have no discernable difference when amplified.  Poorly encoded mp3s with artifacts will. So in theory, a lot of bad mp3's played over really loud sound systems COULD over time damage hearing more than the same piece of music played from a piece of vinyl.


Why do we even care, everything damages our hearing and health anyway? Because a lot of djs are playing terrible mp3s, and a lot more will over the coming years. its just too easy. This is an exploding market in an industry with absolutely no regulation on how much the club owners are allowed to destroy the patrons hearing.  Sure, all the drunk people may not notice. but they also wont notice if I slip GHB in their drink until the next day either.

Can MP3 or other lossy codecs...

Reply #63 –
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Why do we even care, everything damages our hearing and health anyway? Because a lot of djs are playing terrible mp3s, and a lot more will over the coming years. its just too easy. This is an exploding market in an industry with absolutely no regulation on how much the club owners are allowed to destroy the patrons hearing.  Sure, all the drunk people may not notice. but they also wont notice if I slip GHB in their drink until the next day either.
[a href="index.php?act=findpost&pid=320572"][{POST_SNAPBACK}][/a]

Forgive my ignorance and slightly off-topic note, but i think even *if* what you describe is a real problem, it will not be a longterm-issue:

1. Lossy codecs are unprobable to become worse - instead, they will become better and better. This in turn means that over the course of time, lossy encoded files in clubs will also improve, even though they would never be at the "current state-of-the-art".

2. Even though it is a slow process, i have noticed something scary: People are learning how to encode better. It is a very slow process. However, from my observations, the overall quality of MP3s on the net is slowly improving.

3. There are countless other aspects which may be a reason for health-concerns in clubs. The ever increasing amount of clipping and distortion in digital recordings(caused by overzealous limiting and compression in the production-stage) is probably much more noticable than the issue you are describing. So, shall we start a new topic "does clipping damage your ears?".

So, i think even if what you describe is real, then it would not be a longterm-problem.
I am arrogant and I can afford it because I deliver.

Can MP3 or other lossy codecs...

Reply #64 –
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Would you please read
carefully this document
and tell me if you think
it's serious ?

It was a shock when
I read it, can someone tell
me if it can be taken seriously or not ?

I'm really worried...

Thanks.

Here is the document :


http://www.informatik.fh-hamburg.de/~windl...r/MP3-risk.html
[a href="index.php?act=findpost&pid=174531"][{POST_SNAPBACK}][/a]


This article is full of holes in its arguments. If nothing else, you'd have to listen to compressed music files and *never* hear any other sound for the "training" concept, even if were to be true. Not a situation many people would find themselves in, I suspect.

I can't agree with the arguments offered...on the other hand does anyone know of any proper scientific research having been done?

Can MP3 or other lossy codecs...

Reply #65 –
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I've actually had kind of the same teory as this guy, but without all the details... I have a mild case of tinnitus (only notice it when all is quiet). Also, when I'm exposed to louder music (for instance at a bar) it does not take long before my hearing gets bad; sometimes I can't even identify the song playing!

I'm not saying it certainly IS a connection between music compression and tinnitus, but without research -- who knows for sure? 
[a href="index.php?act=findpost&pid=174628"][{POST_SNAPBACK}][/a]


Music compression might be plausible as *the* main culprit for tinnitus if you've never ever

1) listened to recorded loud music that wasn't in a compressed format
2) listened to live loud music

either of those can lead to tinnitus too, *for sure*.

Can MP3 or other lossy codecs...

Reply #66 –
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Music compression might be plausible as *the* main culprit for tinnitus if you've never ever

1) listened to recorded loud music that wasn't in a compressed format
2) listened to live loud music

either of those can lead to tinnitus too, *for sure*.


Nothing has ever been proven to cause tinnitus *for sure*.

Can MP3 or other lossy codecs...

Reply #67 –
I have tinnitus, caused by going to metal concerts and jamming with my band with no hearing protection. I didnt get it from listening to my music at home or otherwise as i've never used the volume to high on anything. You know when you buy an mp3 or Cd player, when you turn it on for the first time, it has a preset volume, like 10 or whatever, i usually leave it at that, or maybe raise a couple of notches if its too low.
we was young an' full of beans

Can MP3 or other lossy codecs...

Reply #68 –
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Quote
Why do we even care, everything damages our hearing and health anyway? Because a lot of djs are playing terrible mp3s, and a lot more will over the coming years. its just too easy. This is an exploding market in an industry with absolutely no regulation on how much the club owners are allowed to destroy the patrons hearing.  Sure, all the drunk people may not notice. but they also wont notice if I slip GHB in their drink until the next day either.
[{POST_SNAPBACK}][/a]


3. There are countless other aspects which may be a reason for health-concerns in clubs. The ever increasing amount of clipping and distortion in digital recordings(caused by overzealous limiting and compression in the production-stage) is probably much more noticable than the issue you are describing. So, shall we start a new topic "does clipping damage your ears?".

[a href="index.php?act=findpost&pid=320645"][{POST_SNAPBACK}][/a]


Sounds like a good Idea. Although this is a slightly different problem they are related and its still very real. 

i created a topic [a href="http://www.hydrogenaudio.org/forums/index.php?showtopic=36430]HERE[/url]

Can MP3 or other lossy codecs...

Reply #69 –
Does anyone have any thoughts on the following text?  Here a guys explains why digital audio broadcasting sounds terrible when a heavilly compressed signal is encoded at 128kbs. Would the same principle apply is compression was applied after encoding?

"On DAB, high levels of audio processing such as those used by Radio 1 cause problems with the encoding of the sound at low bit rates such as 128 kbps. The reason for this is that the aim of perceptual encoding is to use the psychoacoustic model’s masking curves to eliminate frequencies that cannot be perceived by the listener but because the aim of the dynamic range compression is to make the frequency components larger, less of these frequency components will fall below the masking curves. Therefore, the result is that a far larger number of frequency components need to be encoded so more bits are required in order to do this. Different songs are easier for the signal to encode because the signal doesn’t contain many strong frequencies before compression so after amplification there still are few frequencies to be encoded. Other songs however contain a larger number of frequency components after dynamic range compression and at low bit rates such as 128 kbps, the encoder simply runs out of bits. The result for these songs is that the definition and clarity of the music is enormously reduced sometimes to the point where the song sounds worse than if it had been played back from an old cassette tape."
Here is the original text

Can MP3 or other lossy codecs...

Reply #70 –
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Does anyone have any thoughts on the following text?  Here a guys explains why digital audio broadcasting sounds terrible when a heavilly compressed signal is encoded at 128kbs. Would the same principle apply is compression was applied after encoding?

No, it sounds like a one way process to me. It might be that DRC would be less effective if done to a lossy compressed source because the frequencies that it wants to amplify have been erased. Bad effects might happen if the filter is too aggressive and starts amplifying stuff like quantization noise or other undesired signals in preference to the main signal. But you'd have to try it to find out. I'd think it wouldn't be a big deal anyways since few people use that kind of extreme radio compression on their mp3 playback.

But why do you think this has anything to do with hearing damage?

Can MP3 or other lossy codecs...

Reply #71 –
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Quote
Does anyone have any thoughts on the following text?  Here a guys explains why digital audio broadcasting sounds terrible when a heavilly compressed signal is encoded at 128kbs. Would the same principle apply is compression was applied after encoding?

I'd think it wouldn't be a big deal anyways since few people use that kind of extreme radio compression on their mp3 playback.

But why do you think this has anything to do with hearing damage?
[a href="index.php?act=findpost&pid=321424"][{POST_SNAPBACK}][/a]

Clubs use that kind of extreme compression. so mp3s could get recompressed in that form via the dj.

so, if its possible. artifacts and digital clipping would become even more severe when amplified and should be particualrly harsh on the ears.

Can MP3 or other lossy codecs...

Reply #72 –
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so, if its possible. artifacts and digital clipping would become even more severe when amplified and should be particualrly harsh on the ears.

Maybe harsh on the ears as in "sounds ugly". But that is not the same as in "potential for damage".

Listen, if you've read through this thread you know that everyone that has a clue is saying that the only important thing for hearing damage is the decibels of the sound. Standing next to a 110 db diesel engine is exactly as damaging as standing next to a 110 db speaker. People who come out of a club with ringing ears have been exposed to too loud of sound. It doesn't matter whether the club was playing music from CD, live, or 64kbps Xing passed through a FM compressor. It's just the loudness.

Can MP3 or other lossy codecs...

Reply #73 –
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Listen, if you've read through this thread you know that everyone that has a clue is saying that the only important thing for hearing damage is the decibels of the sound. Standing next to a 110 db diesel engine is exactly as damaging as standing next to a 110 db speaker.[a href="index.php?act=findpost&pid=321431"][{POST_SNAPBACK}][/a]


Thats really not correct. If a 110db speaker was to play a 100hz tone, then the diesel engine would be significantly louder(as percieved by the ear, not a meter) and more damaging to the human ear. The diesel engine would contain more frequencies in the range that is particuarly sensitive to the human ear; 1 kHz to 4 kHz. Any sounds that contain more energy in this region are going to be more damaging to the ear.

Can MP3 or other lossy codecs...

Reply #74 –
Well i've researched this too some times ago by asking to all UK audiologists.
Almost all sayd me that the mentioned article is probably a crap and, of course, loud music can damange your hearing.
Anyway there's no official research about lossy audio hearing-related problems.

I'm pretty sure that an extended exposure to compressed audio can't cause physiological problems, anyway my point of view is the audiophile one, which means that i don't have medical backgrounds to claim anything.

I'm just trying to investigate if compressed audio can cause loses of hearing QUALITY, inducting a sort of 'hearing habit' due to the applied audio simplifications. It's not just a physical problem, but psychoacoustical (or neuroacustical in the article).

The 'temporal masking' technique, used in the audio compression, is based on the concept that if we hear a loud sound, then it stops, it takes a little while until we can hear a soft tone nearby.
So, if compressed audio is made of louder sounds only, can we argue that is more 'alterative' than uncompressed ?

Many audiophiles can tell the difference between compressed an uncompressed sounds, so I think that some kind of 'hearing alteration' could happen to compressed audio-only listeners.