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By John
Penner
A lot of people believe that as long as you have a 44.1kHz
sampling rate, and at least 16 bit samples, you're going to get
really good sounding audio.
Having switched over from using my CD player as my primary
source of audio to MP3 files (as they're very handy when you're
working on the computer all the time anyways), and having hooked
up my computer into the AUX input of my stereo system (instead
of using the cheaper PC-speakers), I wanted to find out for myself
just how good MP3 stacks up in sound quality compared to older
formats I used previously on my stereo - CD and VINYL. Don't
laugh, the results were quite surprising.
To get good sound quality, you need to begin with a good SIGNAL
source, good quality components, a quality AMPLIFIER, and good
reproduction - SPEAKERS. in my test, i used a NAD power amplifier,
LINN keleidh speakers ($2000/pair), a typical 44.1/16bit stereo
PC sound card, at 128/bit rate (in MP3), SoundEdit 16 Audio software
(for recording AIFF), and Oliver Dreer's MPEG Audio Creator 2.01
as codec engine. The contender? - A 1968 vintage DUAL turntable
with recent ORTOPHON magnetic cartridge and a stack of vinyl
records.
I took the line-out from the NAD, recording the audio from
the turntable directly into an AIFF file (~40Mb), and then did
an A/B listening test between the original source of the Vinyl
record and the 44.1/16 bit AIFF reproduction of this signal.
The usual assumption of computer users is that if you have
an original sound input source - LINE LEVEL AUDIO coming in,
and when you listen to that line level source, and then record
and digitize that source to a 44.1/16bit stream of digital data,
the theory goes that you should get out the same dynamic range,
clarity, and general sound quality that you put in. I'm afraid
to say - it just ain't so!
After balancing signal levels, I began by switching back and
forth between the original sound source, and the AIFF version
with the "Tape Monitor" button - I was amazed! The
CLARITY, the dynamic RANGE, and the overall IMAGING of the stereo
signal, and SMOOTHNESS of the sound from the vinyl was MUCH better
than the digital reproduction. If you're running on an el-cheapo
computer sound system ($200-300), then you're never going to
know, but if you've got a good quality sound system (say NAD
with LINN speakers), then the difference in dynamic range and
sound quality become very apparent. when i rip'd the AIFF file
into MP3, the loss in FIDELITY was even greater.
A lot of people will say, "no, this isn't so". but
anybody who disagrees has not actually done an A/B listening
test with a GOOD QUALITY turntable & vinyl and a typical PC sound
card (@44.1/16bit) themselves.
so, i would have to conclude that all the claims that MP3
sound is "Good Quality" is all a bunch of marketing
rubbish. this notion only survives because most people haven't
ever actually heard a really good analogue stereo system. You
can listen to what people tell you, or you can try it for yourself
- get the facts. MP3 is an incredible advancement that will change
DISTRIBUTION of music, and is very sensible for getting music
into the PCs we use everyday, but it is ridiculous to continue
having ILLUSIONS that the sound quality is getting better just
because it is digital - that is nothing more than marketing hype.
MP3 files sound great for what they are, but their quality is
only comparable to analogue cassette tape - which for the consumer
masses is generally good enough. but don't think that the sound
you're actually getting is any BETTER!
I will acknowledge that the RANGE in quality of turntables
is much wider than that for CD or MP3 files - it is no secret
that you can get REALLY HORRIBLE sound from VINYL, but that is
if you're using CRAPPY (plastic) turntables, with bad cartridges,
and old used and abused vinyl - your' comparing a worst case
situation to a typical case situation. What most people don't
know is that you can also get better sound from vinyl that you
can from CD (which provides a higher lowest-common denominitar
than vinyl) - if you get a good quality system. Using an el-cheapo
plastic turntable on a CANDLE or EMERSON stereo just won't cut
it. The TURNTABLE makes all the difference: DUAL, B&O, LINN
will all give you better quality than CD out of a turntable,
but most of the record players out there WILL NOT give you better
sound out of a turntable. Since most people aren't willing to
invest in high-end audio, there quality of sound experience actually
gets improved with CDs, so they never realise that the best quality
of sound actually diminishes with CDs/MP3/Digital Audio.
[Note: following are ammendments subsequently made to article]
oh delightful discussion!
as mp3 is a music format, it is refreshing to hear people
start talking about how the music *sounds* instead of talking
about protocols and encoder version numbers. some of you actually
started talking about differnt makes of amplifiers instead of
the version of the encoders you were using.
others of you have brought up such excellent points!
| The reason the author's experiences with digitzied audio
| were so bad was because he used "a typical 44.1/16bit
| stereo PC sound card" for his tests. Generally speaking,
| the A/D converters in typical sound cards are absolutely
| horrible.
- the sound card is the weak link! specifically: the anaglogue
componentry and the A/D + D/A converters.
- CD rippers reading digital data off CD yields better sound
quality because it bypasses the cheap AD/DA converters in the
sound cards.
- vinyl does sound better if you've got a good system, but
typical cases for CD raise the lowest common denominator of sound
experience.
- people are talking about sound being "more detailed"
and if encoding "blurs" or "thins" the sound.
- in the mix of responses, some people's responses indicated
that audio quality after a certain point wasn't as important
as convenience of access to the music.
- raising awareness of quality issues between mp3 and other
medium is considered "anti-mp3 propaganda" (amusing).
the guy is alright though, because he made a good point about
the converters, and suggested a better way of encoding files
(higher bitrate).
some people mentioned that because they didn't care about
the quality of the sound after a certain point, that they couldn't
imagine that sound quality would be any more important to others.
i think they must speak for themselves.
others brought up the convenience/quality of digital audio
was better than that of analogue - records may sound better,
but they're a pain. this is why MP3 will proliferate faster than
vinyl - because the value now is more on convenience than on
sound quality. after a certain point sound quality becomes a
secondary issue to convenience. it is exactly this convenience
(e.g. being able to email a friend or listener a song as an mp3
file), that will radically alter the distribution of music, and
continue to challenge the roles of the currently established
music industry.
there were some really good points about *sonic* qualities
of a medium vs rumble and hiss and noise. the number of people
who evaluate sound on sonic qualities is shrinking compared to
number of people who measure the quality of sound by their "specs"
(hz, db, and sampling rates).
this is exactly what i was trying to do with my article. to
stimulate a disussion going about the sonic qualities of this
sound format (mp3), as oppossed to merely a "spec"
debate. after all, its the way the music sounds that is most
important, all the rest is details.
thank you to all for your comments.
if with the article, i have gotten people to start thinking not
only about the technical & convenience aspects of MUSIC files
(the quantitative aspect) but also of the way they sound MUSICALLY
(qualitative aspect) - then it was worthwhile. :-)
regards,
john.
---
a general response to a long thread of messages...
| Have you ever realized that the soundcard you are using
in your PC
| might be the one messing things up?
| you failed to include information on the sound card.
| Typical sound card? What kind? Were you using good cabling
in
| very short lengths (In fact, your method was completely flawed...
~
| Subject: Are you out OF YOUR MIND?
| How could you expect to get a decent audio recording while
| recording through your PC sound card???
~
| ...what kind of idiot are you for using a cheap PC soundcard,
are
| you a homo?
~
| In your artical at MP3.com, You didn't mention what sound card
you
| were using to output the MP3'S. That also makes a big difference.
| Remember your sound card takes the digital and converts it
to anologe.
| MP3 good for what it is but next time tell what sound card
you are
| using because not all sound cards are created equal. Please
forgive
| my spelling...
~
| Using a standard PC internal audio card to test MP3 or digital
audio
| in general is completely unfair: between the PC's interference
noise
| and cheap DA chips it will degrade the quality of any CD-ripped
| audio into oblivion on playback. It's true that most people
have a
| cheap soundcard and even cheaper PC-speakers to use with MP3,
but
| neither the MP3 standard itself nor CD-audio is tied to this
kind of
| setup. So if you give your records a superlative setup that
most
| people don't have either, you should do the same for all things
| compared. Furthermore...
~
| One thing he totally forget to mention in his article was that
the
| average DAC in a soundboard mildly speaking is crap!...
~
| you used a pretty much average soundcard to do your encoding...
| I have a big problem with this. Not all soundcards are created
equal. ~
| My question to you is: what was the frequency range of the
codec
| you were using?...Also, did you try a higher bit rate? I typically
| encode at 160, not 128.
~
| Test carried out by the MPEG Standard committee have shown
| that with the technical model encoder (developed by
| Fraunhoffer and the MPEG committee), transparent quality
| was achieved at 196 Kbit/sec.
i have been informed by NUMEROUS emails that i should re-perform
the whole procedure with a professional level DAC for sound in/out
if my testing is to be "valid". i agree, and this is
no big news: the sound is only as good as the weakest link -
the DAC was the weak link. also, a higher bitrate than the (usual?)
128 should be used.
but this is not a super-scientific end all and be all test
to prove once and for all that MP3 is or isn't the greatest thing
since sliced bread! this is to get people at home to hook up
their machines, and try things out for themselves. if a dozen
people hooked up their soundcards to their stereos at home somewhere
to try it out themselves instead of listening to someone else's
claims (like mine), then i consider the "article" a
success.
| A friend of mine didn't believe me and accused me of being
an
| audiosnob... so I had to give him *the* listening experience...
| My friend still hasn't recovered.
~
| I've recently conducted my own experiments to determine if
the
| sound quality of MP3 will hold up...After further research,
I
| discovered that the reason for the difference was due to the
| inferior quality of the D2A converter...
~
| HELLO PEOPLE!!!! I keep hearing this crud about LP's or Tapes
| Sounding better. Is not true and can not ever happen.
some people have spent their whole music-listening lives without
having given vinyl a second thought, because CD is the only format
they have actually used (as had i). they have been told "digital
is better than analogue" so many times, they couldn't believe
anything that contradicts that. because of the article, some
people stopped taking someone else's word for it and began to
try it themselves, and their awareness of quality music formats
expanded beyond digital only, and also into the realm of analogue,
and they were appreciative of having their horizons broadened.
others became digital zealouts and resorted to name calling because
they came across an article that didn't praise digital over analogue,
and correctly pointed out that the methods used could have been
improved. others, went waking the dead dogs of "analogue
vs digital" ad nauseum (i must admit the unfortunate naming
of the article set it up for that).
with what i wrote, i merely wanted to raise awareness that
often we are told one thing that sound is so and so good, and
that the old formats don't sound good compared to the new formats.
often the "superiority" of a system is simply accepted
by a lot of people because it is repeated often enough, and not
because so many people have actually tried it themselves and
judged with their own ears. by comparing mp3 with vinyl, i wanted
to raise awareness of this, and several readers did try it and
did hear a difference. some people started talking about musicality,
and sonic quality instead of just bits and bytes. i wanted to
challenge the notion that just because a format has been superseeded
in popular usage does not necessarily make it sound any better
or worse than it ever was. i wanted people to stop talking specs,
and start the critical listening themselves. to make up their
own minds by using their ears. my letter was a seed to get people
experimenting for themselves. HOWEVER, if i had known that it
would be posted as an ARTICLE, i would have edited it much better
in that direction first! it needed a rewrite). it was not to
be the definitive spec report. in this respect it has partially
succeeded, because many of you have reported that because of
the letter/article, you HAVE tried it yourselves - CONGRATULATIONS!
:-)
in general, my rule of thumb is that music recorded on digital
should be played in a digital format, and music recorded on analogue
should be played on analogue. the entire sound-tailoring done
in the mixing and mastering process optimizes for the characteristics
of the used medium. if you prefer analogue or digital depends
most on what you VALUE. depending on your priorities, you will
naturally tend to see one format as superiour to another - and
they are, depending on what criteria you measure them by. in
general however, the less processing put in the path between
recording and playback, the better the sound (digital or analogue).
the best recording is: nothing added; nothing taken away - "transparent".
thanks for all your responses, and most VIGILANT exhortations
to "get a better DAC!" - i will probably do this so
i can work with VISION DSP and get decent sound quality. i will
(and do) listen to music in mp3, on vinyl, and played live -
each has their place. just because digital sound is good, doesn't
make vinyl sound bad - it just means you have two good sounding
formats; different uses - you can't email a vinyl album either
unless you encode it to digital, and that's what brought up this
whole affair in the first place. my father had missed a vinyl
record he had bought long ago ('63), and i wanted to send him
an email with the music as an MP3 attachment so he could hear
his music again. i wrote the letter (posted as an article) after
being amazed at the difference in sound quality before and after
digitization. of course, i could go out and buy a better DAC,
quantize at a better level, etc. as many of you so pointedly
suggested, but my dad still wouldn't have heard his music two
weeks ago if i had waited for all that... he got it as an mp3!
:-)
best regards,
john.
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