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MP3 Audio Bitrate Differences

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ChrisCoaster

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Jun 11, 2008, 11:07:02 PM6/11/08
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Now I don't need to go into what 'kbps" stands for or what 44,000Hz
means, but I was just wondering is what some of your thresholds on
here are when it comes to certain mp3 bitrates.

Particularly, can you hear a difference in the same song recorded at a
bitrate of 96kbps and at 128kbps?

Between 128kbps and 160kbps?

From 160 to, say, 256?

300kbps & up??

For me I can hear a distinct loss at any bit rate below 96kbps. Above
that, not so much.

But when the bitrate exceeds 200kbps, my ears do detect a lot more
punch(dynamic range) in the same song compared to that song at 128k.
The bass is also more solid at bitrates over 200. I don't hear as
much of an extension in the high-frequency, mainly just with the lows.

How about you? How "low" does the bitrate have to be for you to start
to hear loss in sound quality/hissing/metallic sounds typical of low
quality mp3s?

Serge Auckland

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Jun 12, 2008, 3:49:59 AM6/12/08
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"ChrisCoaster" <ckoz...@snet.net> wrote in message
news:dd8fc97e-f9e6-440b...@x41g2000hsb.googlegroups.com...

Here's one set of ratings of the quality at various bit rates.
http://www.mp3-tech.org/tests/gb/index.html

His assessments are pretty much in line with the tests I did about 8 or 9
years ago when MP3 was relatively new.

There's a lot more information on here
http://www.mp3-converter.com/encoders/fraunhofer_encoders.htm

In my own tests, I found 128k quite acceptable for "background" use, and I
agree that 256k provides "CD quality" in that the coded music is
indistinguishable from the CD for all music that I've tried. In fact, some
music can be indistinguishable at much lower rates, but that is somewhat
programme dependent.

For my "holiday hi-fi" I've put about half of my CD collection on a
hard-disc at 320k, gives me a 4:1 space saving on uncompressed, and is
comfortably "CD Quality".

S.

--
http://audiopages.googlepages.com

jamesgangnc

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Jun 12, 2008, 7:53:59 AM6/12/08
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"ChrisCoaster" <ckoz...@snet.net> wrote in message
news:dd8fc97e-f9e6-440b...@x41g2000hsb.googlegroups.com...

I'm using 256k for the apple acc format and not noticing a difference
between that and cds. I listen mostly to rock though and most of it is not
the best music type for a critical test. Disk space being cheap these days
if you have doubts between two I would simply go with the higher one.


Ethan Winer

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Jun 12, 2008, 12:16:51 PM6/12/08
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> I was just wondering is what some of your thresholds on here are when it
> comes to certain mp3 bitrates.

There's no single number because it depends on the music - high-frequency
content, distortion already present, and so forth.

--Ethan

us...@domain.invalid

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Jun 13, 2008, 12:34:47 PM6/13/08
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ChrisCoaster wrote:
> Now I don't need to go into what 'kbps" stands for or what 44,000Hz
> means, but I was just wondering is what some of your thresholds on
> here are when it comes to certain mp3 bitrates.
>
> Particularly, can you hear a difference in the same song recorded at a
> bitrate of 96kbps and at 128kbps?
>
> Between 128kbps and 160kbps?
>
> From 160 to, say, 256?
>
> 300kbps & up??
>

I am being very conservative in this. I use LAME VBR in the 155-180
kbps range and truly cannot hear a difference from the uncompressed files.

However, there is a caveat: this is classical music with not all that
high high frequency content, and, I am old enough that I can't tell
the difference between the original and the original with a sharp cutoff
at 13.5 kHZ ... so the files have a sharp cutoff at 13.5 kHz.

In fact, at about 120 kbps I am hard pressed to say that the files
sound different. Perhaps, for some files. At 96 kbps fixed rate,
yes, there are almost always clear differences. At 80 kbps fixed rate,
there are major, distressing, differences. Remember, this is pre-filtered at
13.5 kHz. Also, I am telling LAME to try its best at that average bitrate.

Also, and I know people will attack me for this, I listen to the
difference file between the original (filtered) file and the
lossy compressed one, decompressed and correctly time-aligned.
At the 160 kbps rate, the difference sounds like slightly
colored pink noise. At 96 and especially 80 kbps, it begins to
sound like a choir of chirping canaries in difficult passages.


Doug McDonald


ChrisCoaster

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Jun 14, 2008, 8:37:05 AM6/14/08
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___________________
Thanks Doug "Did somebody say?" McDonald. :D and everybody else who
joined in here.

I already had a gut instinct about what was confirmed in this thread.
Go with the higher bitrates!!!

So it's pretty safe to assume, stay above 200kbps as much as possible
if it's fidelity that matters.
The only problem is, I've got to watch out for a 256kbps RECORDING of
a 96k file! Them'll getchya every time.
"Why does this high-bitrate piece sound like it's inside a coffee
can?!" LOL! :(

regards,

-CC

Steven Sullivan

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Jun 19, 2008, 4:01:20 PM6/19/08
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Serge Auckland <sergea...@btinternet.com> wrote:

> "ChrisCoaster" <ckoz...@snet.net> wrote in message
> news:dd8fc97e-f9e6-440b...@x41g2000hsb.googlegroups.com...
> > Now I don't need to go into what 'kbps" stands for or what 44,000Hz
> > means, but I was just wondering is what some of your thresholds on
> > here are when it comes to certain mp3 bitrates.
> >
> > Particularly, can you hear a difference in the same song recorded at a
> > bitrate of 96kbps and at 128kbps?
> >
> > Between 128kbps and 160kbps?
> >
> > From 160 to, say, 256?
> >
> > 300kbps & up??
> >
> > For me I can hear a distinct loss at any bit rate below 96kbps. Above
> > that, not so much.
> >
> > But when the bitrate exceeds 200kbps, my ears do detect a lot more
> > punch(dynamic range) in the same song compared to that song at 128k.
> > The bass is also more solid at bitrates over 200. I don't hear as
> > much of an extension in the high-frequency, mainly just with the lows.
> >
> > How about you? How "low" does the bitrate have to be for you to start
> > to hear loss in sound quality/hissing/metallic sounds typical of low
> > quality mp3s?

> Here's one set of ratings of the quality at various bit rates.
> http://www.mp3-tech.org/tests/gb/index.html


1998 is a long time ago, in MP3 development.

128kbs has gotten a LOT better since then.


--
-S
Poe's Law: Without a winking smiley or other blatant display of humorous
intent, it is impossible to create a parody of a religious Fundamentalist that
SOMEONE won't mistake for the real thing.

Steven Sullivan

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Jun 19, 2008, 4:05:03 PM6/19/08
to

Not really. 192 VBR is probably just as good, if you use a good encoder (like LAME
3.XX).

check out this 'faq'.

http://www.hydrogenaudio.org/forums/index.php?showtopic=28124.

And compare encodes yourself, using ABX software

http://www.kikeg.arrakis.es/winabx/

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