
Do 320kbps mp3 files really sound better? Take the test - mike_esspe
http://www.noiseaddicts.com/2009/03/mp3-sound-quality-test-128-320/
======
lmm
Asking which file sounds "better" is meaningless; some distortions sound good.
The proper way to do this is an ABX test, where you compare both to a known
original, and ask which sounds _more like the original_.

~~~
cskau
Do you have any links?

~~~
dsirijus
I may not disclose full details, but one of the engineers that made particular
widely used audio decoder said that they've left the bug whose symptoms were
slight high frequency noise.

It was widely reported to sound "better" than other "by the book"
implementations.

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antonios
This is meaningless. Statistically meaningful tests are performed using ABX
testing methods (<http://en.wikipedia.org/wiki/ABX_test>) with high-quality
equipment. And, yes, many people have trained ears (and brains?) that can
easily distinguish the artifacts made by the MP3 compression even in 320kbps.
See this ([http://listening-
tests.hydrogenaudio.org/sebastian/mp3-128-1...](http://listening-
tests.hydrogenaudio.org/sebastian/mp3-128-1/results.htm)) as an example of an
ABX test.

As for me, with my current medium-quality headphones, I can't distinguish
between the original and an 128kbps mp3.

~~~
simonbrown
So if you end up listening to the music with your medium-quality headphones,
it doesn't matter whether it's 128kbps or 320kbps.

~~~
antonios
Yes. For _me_, using _my headphones_, it doesn't matter. Everyone's experience
is unique, as it depends on various factors.

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oliwarner
The difference is tiny but just about audible.

To my ears _neither_ sounded like a good quality recording and I think that's
what made it so hard to tell the difference. Even with cheap speakers, it's
easy to spot compression artifacts in poorly encoded audio but in these
samples the drum tracks on both sound "mashed". That might be an instrumental
trait but it sounds more like a production or postprocessing error to me.

------
calciphus
Much more interesting test:

[http://www.codinghorror.com/blog/2012/06/the-great-
mp3-bitra...](http://www.codinghorror.com/blog/2012/06/the-great-mp3-bitrate-
experiment.html)

And the outcome:

[http://www.codinghorror.com/blog/2012/06/concluding-the-
grea...](http://www.codinghorror.com/blog/2012/06/concluding-the-great-
mp3-bitrate-experiment.html)

~~~
lmm
Again, not an ABX test. No wonder the first file did best - it sounded most
like the first file. You can't do listening tests without a labelled original
to compare to.

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andrewfelix
Do the test with Thelonius Monk.

I didn't think I was an audiophile, until I noticed a crispness missing from
some of my jazz. I encode at 320kbps out of paranoia now, but what's an extra
few megabytes per album?

FYI if anyone is using Google Music, turn on HTML5 audio (via labs). I swear
there is a perceptible improvement.

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andybak
And the audiophile loons start appearing in the comments: "on high end gear
you can hear the difference between a factory and a copied CD.".

No. You can't, sir.

~~~
some1else
Basic DSP knowledge tells us that a digital audio copy is exactly the same
quality as the original.

Also, testing the difference between 128kbps and 320kbps MP3s over and over
again is like drinking warm beer all the time to make sure it's really worse
than the cold one.

~~~
einmus
Audio CD is an old technology. It doesn't have advanced error correction
method. With poor quality CD-R, it's true that the quality is not the same.

~~~
andybak
Excluding from skipping and audible glitches that doesn't sound plausible.

i.e. copying an audio CD can create gross errors but not a more subtle change
in audio quality (loss of dynamics/frequencies etc).

If you disagree could you point me towards some evidence?

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lucb1e
Yup, tested this before. Also with quite good hardware (sound card,
circumaural quality headphones), between 128kbps and 192 you're already not
sure whether there a difference or not, but anything above 192 is really
wasted effort.

~~~
rustynails
128kbit sounds so poor that I get a headache from listening to it. There is a
tinnyness and high pitched squeal that is like a drill through my head. Maybe
it's like using a 14" monitor - if you're so used to hearing low bitrate, it
may be hard to notice better quality when you hear it occasionally.

------
nodesocket
Bad choice for the sample. I however still picked #1. Choose a song with bass,
and mids. The difference between 128kbps and 320kbps will become painfuly
obvious.

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andybak
192kbs VBR with a good encoder. There's been countless tests and this is
indistinguishable to the vast majority of listeners (teens might have a slight
edge as the ability to hear high frequencies diminishes with age).

I don't have time to dig up citations but check out the Hydrogen Audio forums
and other sane, non-cranky-audiophile, evidence based sources.

~~~
rustynails
I would say that 192kbit (2 pass, VBR) is the minimum bitrate that one should
encode music. I can pick lower than this without trying. I do struggle to hear
more than 192kbit, except occasionally at the high end. In reality, disk is so
cheap that I encode in flac. I'd rather keep myself future proof. Let's just
say that my entire cd collection is smaller than 2 bluray rips at 1080p.

------
ojiikun
A 10-second sample misses the point of HQ v. LQ: a very few sections of most
albums will sound better at HQ. The vast, vast majority of songs will sound
the same. The point isn't that HQ is a little better most the time, it's that
some of the time it is much better.

LTJ Bukem - Watercoulours comes to mind as a great example of the phenomenon.

------
palebluedot
Very interesting. This then set me off reading about ABX testing for longer
than I wish to admit. For those looking to try some ABX testing between
320kbps and 128kbps mp3 files, this is the best in-browser one I've found so
far: <http://mp3ornot.com/>

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zmitri
If you have quality headphones I don't think it's very hard. On earbuds, or
laptop speakers, almost impossible. Put it on a real stereo and you will also
be able to.

Perhaps the fact that music is now being produced and optimized to sound good
on tinny speakers is altering what we perceive to be a "good sound."

~~~
oe
I think the difference was noticeable even on laptop speakers.

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invisiblea
Laptop speakers: Nope. High Quality Headphones: Maybe. Loud sound system in a
crowded club: Definitely.

Also just because one track sounds acceptable at 192, doesn't mean another
will. The only way to make sure tracks have the same 'opportunity' to sound
good is to throw away less information.

------
danieldk
I picked the higher one correctly. Though, the difference is barely audible on
my laptop (MacBook Pro aka worthless DAC, but quite ok Sennheiser
microphones).

Personally I like lossless for practical reasons (e.g. conversions without
quality loss).

~~~
aes256
> Personally I like lossless for practical reasons (e.g. conversions without
> quality loss).

That was the clincher for me. At first my music collection was a mish-mash of
different bitrates. I converted the whole lot to the LAME V2 preset (~192kbps
VBR) a la the mp3 scene standard, then no sooner had I done that than the
standard changed to V0 (~245kbps).

Screw it, I figured. Storage is cheap. Might as well go lossless.

------
cabirum
It's just the audio sample is not complex enough to hear the difference, from
the encoder POV.

Try doing the same test with some orchestra recording or any metal band of
your preference, even 320 vs lossless would be noticable.

------
1SaltwaterC
At work, with crappy Microsoft LifeChat LX-3000 there's a barely noticeable
difference. Can't tell which is which anyway. Need to try at home with a
proper setup.

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klez
I cheated... the first one took a bit more to buffer, so I inferred it was the
highest bitrate.

Anyway, with the cheap headset I have at work, yeah, I didn't notice any
difference.

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esolyt
I would argue this song is terrible for this test. I usually can instantly
tell the difference between 320 and 128 kbps, but I wasn't able to with this
test.

~~~
jvdh
It might be my bad quality headphones, but the song for me was so distorted on
the 128kbps that I heard the difference in less than a second.

------
lutusp
Obviously for the author's signal source, the original CD sound tracks
(sampled at 44.1 KHz * ) would limit the importance of a change from 128 to
320 kbps.

* Corrected units

~~~
lmm
No, this is wrong. CDs are sampled at 44.1khz with 16-bit samples, making for
(calculates) 706kbps. And that's ignoring stereo.

~~~
lutusp
The depth of the sample doesn't get around the Nyquist-Shannon sampling
limitation. This means resampling a 44.1 KHz * recording at a higher bit rate
is pointless.

To be specific, a 44.1 KHz sampling rate provides a bandwidth of 22.05 KHz,
period, full stop.

[http://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_samplin...](http://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_sampling_theorem)

<http://en.wikipedia.org/wiki/Sampling_rate>

A quote: "The full range of human hearing is between 20 Hz and 20 kHz.[3] The
minimum sampling rate that satisfies the sampling theorem for this full
bandwidth is 40 kHz. The 44.1 kHz sampling rate used for Compact Disc was
chosen for this and other technical reasons."

* Corrected units

~~~
ethereon
I believe you're messing up the units here.

\- The sampling rate, measured in kHz, for CD tracks is 44.1 kHz (not kbps),
which determines the frequency range. Nyquist-Shannon applies to this.

\- The bit-depth, number of bits/sample, determines the SNR of the signal, but
has no effect on the frequency range. A typical audio CD has a bit depth of
16.

\- The bit-rate, measured in kbps, is (sampling_rate * bit_depth *
channel_count). So for an audio CD, this would be 441000 * 16 * 2 = 1411200
bps = 1411.2 kbps.

~~~
lutusp
> The sampling rate, measured in kHz, for CD tracks is 44.1 kHz (not kbps) ...

Yes, corrected, thank you. The original point stands -- the higher resampling
rates are increasingly pointless.

> The bit-depth, number of bits/sample, determines the SNR of the signal ...

Yes, and is thought to be the source of the much-remarked, subtle difference
between vinyl album music and CD music. But no one knows for sure.

> The bit-rate, measured in kbps, is (sampling_rate * bit_depth *
> channel_count). So for an audio CD, this would be 441000 * 16 * 2 = 1411200
> bps = 1411.2 kbps.

True. Unfortunately, these numbers may motivate people to argue for higher and
higher MP3 sampling rates, ignoring the fact that the original temporal
sampling rate severely limits the usefulness of these efforts.

~~~
lmm
>The original point stands -- the higher resampling rates are increasingly
pointless.

If we were talking about _sampling_ rates it would. But we're not, we're
talking about _bit_ rates.

Any MP3 of a CD, whether 128kbps, 192kbps, 320kbps or something else, will
still have a _sample_ rate of 44.1kHz. Resampling at 128kHz would indeed be
stupid and pointless, and would also result in a much larger file than the
original CD. That is not what mp3 does; it takes your 16bits@44.1kHz CD
bitstream, and gives you a compressed bitstream that will, when decompressed,
give you another 16bits@44.1kHz bitstream which sounds similar. The bitrate
measures the size of this compressed bitstream, and therefore gives an
indication of how much information (in the technical sense) you must have
discarded to form it. But it's entirely unrelated to the sampling rate - you
can't even say bitrate = sampling rate * bit depth when we're talking about a
compressed bitstream.

------
stuaxo
Should test against lossless.

Bus driver - imaginary places has really fast rapping, as mp3 its almost
impossible to understand, on lossless you can grok it.

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dsirijus
You just need to focus on percussion to get it right - it's much more complex
frequency-wise.

I personally break even at V2.

~~~
tfb
You're right. That's what I ended up focusing on after a few listens and chose
the correct answer, which could probably be attributed to being an ex pro
drummer. Most people were probably focusing on the vocals, not at all attuned
to what quality percussion sounds like, which is why more people chose the
wrong answer. One might even go far as to say that more people think vocals
sound better at 128 than 320.

~~~
dsirijus
That's also why I spent more than half my budget on percussion in equipping my
ex garage band.

And that's also why you can see Jack White playing a $50 guitar and no drummer
without some serious dough investment in their equipment.

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SwaroopH
Looks like I chose the higher one but you are right, hardly any difference.

------
NickKampe
Terrible test case

