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Are my ears broken?
chengbin
post Dec 17 2009, 04:49
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This post is to discuss two issues I'm experiencing (or rather, hearing).

All test are listened on Foobar2000. MP3 are encoded with VFR slow mode.

1. @ 128Kbps VBR MP3 (lame 3.98.2) sounds better than 110Kbps (NeroAAC, q 0.4) AAC?!?! I thought AAC > MP3???

2. Lame's V5 (around 130Kbps) sounds pretty much transparent to me. I'm using a pair of head direct RE0, which is supposed to be an incredibly revealing pair of earphones.

I tested it with Kelly Clarkson's Breakaway, Train's Drops of Jupiter, and Tchaikovsky's 1812 overture. I didn't do a blind test, I knew which one is which and I switched back and forth.

As much as a want to think my lossless one sounds better, I couldn't. I honestly could not hear a difference.

That can't be right. People say that 128 is horrible, especially when I have revealing earphones like my RE0. There are people on head fi saying that they can easily hear the difference between 192Kbps MP3 and FLAC with their RE0.

Are my ears broken? I think my hearing isn't that bad. I listen at around 55dB all the time (even on the subway thanks to Shure's excellent tips). I don't think I have much hearing lost.
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Heliologue
post Dec 17 2009, 04:56
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Without an ABX test, there's no way of telling if your described discrepancy is real or imagined.

Per the ToS #8, there is no such thing as "sounds better" until you can prove it.

That being said, I'm not at all surprised that a well-encoded MP3 is (apparently) transparent to you; that sounds about normal, in fact. The people telling you can hear the difference between a FLAC file and a well-encoded MP3 file are lying to you.
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kornchild2002
post Dec 17 2009, 04:59
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1. The mp3 files had a bitrate of at least 18kbps higher than the AAC ones. That is a rather large difference. When comparing lossy encoders, you need to use the same bitrate ranges. For example, comparing a 128kbps AAC file with a 130kbps mp3 file would be more than acceptable that testing files with an 18kbps difference.

2. And? That just means that the lossy encoder (Lame) is doing its job. That doesn't mean that your ears are borken or that you don't appreciate the music. It just means that Lame is performing as it should.

You really should conduct blind ABX tests though as sighted tests are flawed by the placebo affect. Additionally, dedicated users here will tell you to determine what lossy encoder and setting is right for you. Only you have the combination of your music, equipment, listening environment, and ears. Personally, I find Lame at -V 5 to be quite transparent for a bunch of my content when I am casually listening to the songs. Lastly, this definitely isn't the first (and it won't be the last) time people at head fi were spreading bad advice, making up audio quality stats, or formulating outrageous statements. Nothing is wrong with your ears. Enjoy your music at -V 5. At least you will be able to fill your portable player/computer with more songs than those people who worry about carrying around PCM WAV files (because they think FLAC and mp3/AAC/WMA/OGG sound bad) on their 2GB portables.
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chengbin
post Dec 17 2009, 05:03
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QUOTE (Heliologue @ Dec 16 2009, 22:56) *
Without an ABX test, there's no way of telling if your described discrepancy is real or imagined.

Per the ToS #8, there is no such thing as "sounds better" until you can prove it.

That being said, I'm not at all surprised that a well-encoded MP3 is (apparently) transparent to you; that sounds about normal, in fact. The people telling you can hear the difference between a FLAC file and a well-encoded MP3 file are lying to you.


The MP3 vs AAC test is very obvious. The MP3 retained bass and treble far better than NeroAAC that telling which one is which is incredibly easy. Again, my bias is with AAC, and my mind is telling me that MP3 is better.

If anything is imagined, it should be me imagining the one I bias against sounding better, and in both of my case, I couldn't imagine that. My mind is telling me the opposite. I think blind test is unnecessary when under bias I still favor the other one.

I'm just shocked that such a low bitrate MP3 can make me think it is transparent, especially when my earphones are of very high quality.
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greynol
post Dec 17 2009, 05:06
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QUOTE (chengbin @ Dec 16 2009, 20:03) *
The MP3 vs AAC test is very obvious.

We don't care.

Make an effort to demonstrate that you're willing to comply with TOS #8 or go away. It's that simple.


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chengbin
post Dec 17 2009, 05:08
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QUOTE (greynol @ Dec 16 2009, 23:06) *
QUOTE (chengbin @ Dec 16 2009, 20:03) *
The MP3 vs AAC test is very obvious.

We don't care.

Make an effort to demonstrate that you're willing to comply with TOS #8 or go away. It's that simple.


Can anybody recommend a way to do a blind test without involving another person?
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greynol
post Dec 17 2009, 05:09
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Install foobar2000 with ABX plug-in option.

http://www.foobar2000.org/components/view/foo_abx

This post has been edited by greynol: Dec 17 2009, 05:10


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chengbin
post Dec 17 2009, 05:28
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QUOTE (greynol @ Dec 16 2009, 23:09) *
Install foobar2000 with ABX plug-in option.

http://www.foobar2000.org/components/view/foo_abx


I got the plugin loaded. How do I use it?? I'm using Foobar 1 beta 4 portable version (like 0.9.4.5's interface a lot better).

This post has been edited by chengbin: Dec 17 2009, 05:29
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Qest
post Dec 17 2009, 05:38
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QUOTE (Heliologue @ Dec 16 2009, 20:56) *
The people telling you can hear the difference between a FLAC file and a well-encoded MP3 file are lying to you.


I used to think so too, and my dad told me there was a difference. I said, 'riiiiighhht' and one day I set up a little experiment with a whole crapload of formats (128, 192 and 256 mp3's, a ~500kb ogg and the original lossless). In a few double blind tests, my dad was able to put them in order of bitrate without even hesitating every time (it was pretty obvious to me also, listening with him). Anyways... his stereo is a little nuts and he even buys into some of that snake oil garbage, but an experiment is an experiment.

Now I say that anyone who says you can't hear the difference between lossy and lossless just needs better equipment.

So maybe your ears aren't the problem, chengbin. What's your source on those RE0's?
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greynol
post Dec 17 2009, 05:39
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QUOTE (Qest @ Dec 16 2009, 20:38) *
Now I say that anyone who says you can't hear the difference between lossy and lossless just needs better equipment.

...and what you say about needing better equipment is actually a myth, but whatever.

Do you have any other details to give us to go along with your anecdote (ABX logs, encoder(s) used and what settings, etc.)?

This may be obvious to those who do this regularly, but what double-blind protocol allows one to order multiple files by bitrate exactly?

This post has been edited by greynol: Dec 17 2009, 05:52


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greynol
post Dec 17 2009, 05:49
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QUOTE (chengbin @ Dec 16 2009, 20:28) *
I got the plugin loaded. How do I use it??

Load two files, select them and right-click. You'll see the option to ABX them under Utils.


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Qest
post Dec 17 2009, 06:18
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QUOTE (greynol @ Dec 16 2009, 21:39) *
Do you have any other details to give us to go along with your anecdote (ABX logs, encoder(s) used and what settings, etc.)?


Nope. Not logs or nothing. I wasn't trying to prove anything, just make my dad look like an idiot. I just renamed them randomly and then burned the randomly named files in a random order a few times over and then after the experiment checked the logs to see what was what.

Undoubtedly, you could find something wrong with the experiment, but it changed my views.

Feel free to dismiss my anecdote, greynol. I may have come on too strong with my statement; this is not an argument I care to start, just one man's opinion.

QUOTE (greynol @ Dec 16 2009, 21:39) *
...and what you say about needing better equipment is actually a myth, but whatever.


Though this does make me curious as to what kind of system you do your tests on?
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greynol
post Dec 17 2009, 06:30
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It doesn't matter what system I use since I don't claim to have golden ears. What I have read by those who do is that high end equipment doesn't help (this is an anecdote, of course). Lossy encoding models assume a flat frequency response upon playback (this is not an anecdote). On the flipside however, systems and/or environments with high levels of noise can help in masking some artifacts.

Here are a couple of links:
http://www.hydrogenaudio.org/forums/index....mp;#entry621426
http://www.hydrogenaudio.org/forums/index....mp;#entry539257

This post has been edited by greynol: Dec 17 2009, 06:56


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andy o
post Dec 17 2009, 09:03
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Qest, the "better equipment" gambit is a fallacy because the compression artifacts are reproducible with any decent equipment, even "cheap" ones.

AFAIK there are people here that have ABX'd correctly certain 320 kbps MP3 samples, and I don't think they use audiophile equipment (correct me if I'm wrong). They just know what to hear.
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Martel
post Dec 17 2009, 10:10
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QUOTE (greynol @ Dec 17 2009, 05:39) *
...and what you say about needing better equipment is actually a myth, but whatever.
If you have an equipment which is not able to reproduce above 16kHz without audible attenuation or FR distortion, then you can hardly tell a difference between two encodings which differ mostly in the 16kHz+ range (as is usually the case with low vs. hi bitrate lossy)...

If you had an equipment which does 20kHz within +-3dB tolerance, it might be, in this context, called a better equipment and it would be needed to tell the difference (provided you are able to hear above 16kHz).


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chengbin
post Dec 17 2009, 14:05
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QUOTE (greynol @ Dec 16 2009, 23:49) *
QUOTE (chengbin @ Dec 16 2009, 20:28) *
I got the plugin loaded. How do I use it??

Load two files, select them and right-click. You'll see the option to ABX them under Utils.


I feel so stupid. I looked at every menu, but forgot right click...

The ABX is very interesting. The fact that I can switch the file right away is so useful.

Anyways, I did it for Kelly Clarkson's Breakaway 3 times. I got it right 2/3 times. I *think* I heard a difference, but it might have been my brain, which is why I think I guessed the first 2 right. But honestly, I couldn't hear a difference. They sounded 99.99% same for me.

QUOTE (Martel @ Dec 17 2009, 04:10) *
QUOTE (greynol @ Dec 17 2009, 05:39) *
...and what you say about needing better equipment is actually a myth, but whatever.
If you have an equipment which is not able to reproduce above 16kHz without audible attenuation or FR distortion, then you can hardly tell a difference between two encodings which differ mostly in the 16kHz+ range (as is usually the case with low vs. hi bitrate lossy)...

If you had an equipment which does 20kHz within +-3dB tolerance, it might be, in this context, called a better equipment and it would be needed to tell the difference (provided you are able to hear above 16kHz).


I don't think earphones can go up to 20kHz +-3dB. The RE0 is by far the treble earphone, extending higher than any other earphones out there, but I don't think it'll reach 16kHz without some dropping. I've seen many earphone FR graphs that are like -30dB at 20kHz.

Time to grab a tone generator to see how high I can hear.

EDIT: I'm surprised. I can only hear up to 18kHz square wave.

This post has been edited by chengbin: Dec 17 2009, 14:14
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pdq
post Dec 17 2009, 15:01
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QUOTE (chengbin @ Dec 17 2009, 09:05) *
Time to grab a tone generator to see how high I can hear.

EDIT: I'm surprised. I can only hear up to 18kHz square wave.

This is not the proper way to test for this. What matters is the ability to hear those high frequencies in real material with other frequencies present at the same time.

What you should do is take a piece that you know has lots of high frequencies. Then apply lower and lower low-pass filters until you can hear the difference. You will probably find that this occurs several kHz below where you can hear a pure tone.
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chengbin
post Dec 17 2009, 15:11
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QUOTE (pdq @ Dec 17 2009, 09:01) *
QUOTE (chengbin @ Dec 17 2009, 09:05) *
Time to grab a tone generator to see how high I can hear.

EDIT: I'm surprised. I can only hear up to 18kHz square wave.

This is not the proper way to test for this. What matters is the ability to hear those high frequencies in real material with other frequencies present at the same time.

What you should do is take a piece that you know has lots of high frequencies. Then apply lower and lower low-pass filters until you can hear the difference. You will probably find that this occurs several kHz below where you can hear a pure tone.


I can't edit my post my post for some reason. I don't know why I wrote square wave. I used sine waves.

I can hear perfectly at 18kHz. At 19kHz I couldn't hear anything (unless I turn my speakers way up).

I really don't think I know any songs with >18kHz material.
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Fandango
post Dec 17 2009, 15:20
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QUOTE (greynol @ Dec 17 2009, 06:30) *
Lossy encoding models assume a flat frequency response upon playback (this is not an anecdote).

Exactly, and therefore one can imagine what boosting the treble does wonders when ABXing lossy codecs... wink.gif

Of course you can cheat with an equalizer, or maybe the "better equipment" isn't so good after all and amplifies or distorts high frequencies.
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kornchild2002
post Dec 17 2009, 15:39
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QUOTE (chengbin @ Dec 17 2009, 06:05) *
Anyways, I did it for Kelly Clarkson's Breakaway 3 times. I got it right 2/3 times. I *think* I heard a difference, but it might have been my brain, which is why I think I guessed the first 2 right. But honestly, I couldn't hear a difference. They sounded 99.99% same for me.


Most proper blind ABX trials include about 10-15 "guesses" per song. Going a total of 3 times doesn't show anything. You could have correctly guessed or you could have actually been hearing a difference. Now, getting a 9/10 or 14/15 means that you likely heard a difference (assuming you are comparing the source lossless file with the lossy version) and the lossy file doesn't sound as good. Additionally, as previously said, you need to test your frequency hearing abilities with actual music and not just sound waves (whether they are square or not). People can often hear tones up in the ~19KHz range but they hear music up around the 16KHz range. That is a big difference.
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Martel
post Dec 17 2009, 15:42
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QUOTE (chengbin @ Dec 17 2009, 14:05) *
I don't think earphones can go up to 20kHz +-3dB. The RE0 is by far the treble earphone, extending higher than any other earphones out there, but I don't think it'll reach 16kHz without some dropping. I've seen many earphone FR graphs that are like -30dB at 20kHz.
With headphones, you can't just compare to a flat frequency response but you need to measure it relative to some other curve whose name I forgot (but it is far from a flat line and is probably a function of the speaker's distance from the ear). Measuring this is really complicated for headphones.
QUOTE (chengbin @ Dec 17 2009, 14:05) *
Time to grab a tone generator to see how high I can hear.
EDIT: I'm surprised. I can only hear up to 18kHz square wave.
http://www.audiocheck.net/audiotests_frequencycheckhigh.php
Try this test instead of the square wave.


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chengbin
post Dec 17 2009, 17:49
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QUOTE (kornchild2002 @ Dec 17 2009, 09:39) *
QUOTE (chengbin @ Dec 17 2009, 06:05) *
Anyways, I did it for Kelly Clarkson's Breakaway 3 times. I got it right 2/3 times. I *think* I heard a difference, but it might have been my brain, which is why I think I guessed the first 2 right. But honestly, I couldn't hear a difference. They sounded 99.99% same for me.


Most proper blind ABX trials include about 10-15 "guesses" per song. Going a total of 3 times doesn't show anything. You could have correctly guessed or you could have actually been hearing a difference. Now, getting a 9/10 or 14/15 means that you likely heard a difference (assuming you are comparing the source lossless file with the lossy version) and the lossy file doesn't sound as good. Additionally, as previously said, you need to test your frequency hearing abilities with actual music and not just sound waves (whether they are square or not). People can often hear tones up in the ~19KHz range but they hear music up around the 16KHz range. That is a big difference.


Can you recommend some songs that has music with that high of a frequency?

I'll do a 15 guess ABX test in the evening. I got to go somewhere later, and watch a movie after.

QUOTE (Martel @ Dec 17 2009, 09:42) *
QUOTE (chengbin @ Dec 17 2009, 14:05) *
I don't think earphones can go up to 20kHz +-3dB. The RE0 is by far the treble earphone, extending higher than any other earphones out there, but I don't think it'll reach 16kHz without some dropping. I've seen many earphone FR graphs that are like -30dB at 20kHz.
With headphones, you can't just compare to a flat frequency response but you need to measure it relative to some other curve whose name I forgot (but it is far from a flat line and is probably a function of the speaker's distance from the ear). Measuring this is really complicated for headphones.
QUOTE (chengbin @ Dec 17 2009, 14:05) *
Time to grab a tone generator to see how high I can hear.
EDIT: I'm surprised. I can only hear up to 18kHz square wave.
http://www.audiocheck.net/audiotests_frequencycheckhigh.php
Try this test instead of the square wave.


I can start to hear 19kHz (tingle in my ear feeling). At 18kHz it is very "loud" (I can hear it very clearly)

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greynol
post Dec 17 2009, 18:00
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Please read this:
http://www.hydrogenaudio.org/forums/index.php?showtopic=7516
It's a sticky at the top of the General Audio forum. The title says "Read before posting".

and this:
http://www.hydrogenaudio.org/forums/index....showtopic=16295
You see that an ABX run of only three trials is meaningless.

Here are some samples of real music with various low passes applied (mustang.flac):
http://ff123.net/samples.html


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2Bdecided
post Dec 17 2009, 18:18
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Point 1 looks like a TOS 8 violation, but the rest of the OP's post is saying "I can't hear a difference", and the 3-trial ABX was followed by "I can't hear a difference" - so I'm not sure we need to chase ABX results there.

@chengbin, your experience is normal. The audible differences are subtle - not usually night-and-day. People who always "hear" night-and-day differences between any two pieces of audio equipment (cables, amplifiers, CD tranports, and codecs at near-transparent bitrates) are usually imagining these differences.

People adopt this terminology from hi-fi magazines, which try to convince you that this year's must-have is night-and-day better than what was around last year. If things were really improving so quickly, they must have been truly awful ten years ago! (they weren't wink.gif ) So, don't expect night-and-day differences. For many people saying they hear such things, it's a case of The Emperor's New Clothes.



There are general but subtle audible problems in the <128kbps region with mp3 - quite serious problems with some specific kinds of sounds. Once you give the format room to "breathe" by going above -V5 these problems become so subtle that, apart from those "problem" signals, it's mostly transparent to most people.


btw, equipment with a horrible irregular frequency response can reveal artefacts that equipment with an accurate flat frequency response will not reveal. If you boost a narrow frequency region by 10-20dB, it's going to reveal coding noise that was otherwise masked. This is a fault of the equipment, not the codec. Such equipment isn't "revealing" - it's trash.


One exception: Headphones aren't supposed to have a flat frequency response - they're supposed to simulate the frequency response of the part of the system that's missing (i.e. speakers > outer ear) which, due to the shape of the head and outer ear, isn't flat at all. That's OK - that won't break any codec - that just makes them as close as possible to normal listening.

Cheers,
David.

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greynol
post Dec 17 2009, 18:25
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QUOTE (2Bdecided @ Dec 17 2009, 09:18) *
One exception: Headphones aren't supposed to have a flat frequency response - they're supposed to simulate the frequency response of the part of the system that's missing (i.e. speakers > outer ear) which, due to the shape of the head and outer ear, isn't flat at all. That's OK - that won't break any codec - that just makes them as close as possible to normal listening.

I've often wondered how much of an impact this has in helping people successfully ABX with headphones.


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