On 23 Jun, 06:44, "Colin B." wrote:
In rec.audio.tech Dave wrote:

I have been disappointed with the audio quality of some CDs I have
bought recently. Is there a free program I can use to get an accepted
measurement of fidelity? (like a signal to noise ratio)

I have my suspicious that some may have been stored an MP3s and then
"unripped" in the factory. So how can I tell for certain if my CD has
been an MP3, or other lossy format? I'd hope mp3 storage would leave
different markers than the original tape, for example.

Unless these are pirated copies, the answer is most likely not. That's
too much pointless effort for commercial studios to go through.

The answer is much more mundane: Most recording sucks.
Maybe I should retrain when I get to 50 because by then all younger
sound engineers will have grown up with MP3s and not have a clue what
decent audio sounds like.

In article ,
Colin B. wrote:
There's a far more mundane explanation. Recent
music distribution, including CDs, have suffered
from an industry-wide of sever over compression,
limiting and clipping, as an endemic result of the
mastering process.

I'd suggest that this isn't a recent phenomenon. I've got plenty of pop
vinyl from the 1970s and 1980s that has roughly no dynamics. Making crap
sound louder on the radio at the complete expense of quality is decades
old.

There's a difference in how this was acheived, though. In older days it
was through the arrangement of the music and studio recording practices.
The Phil Spector 'wall of sound' for example.
These days it's done using largely automatic processors after the studio
recording is signed off. Similar to the types used for processing radio at
the transmitters.

--
*Does fuzzy logic tickle? *

Dave Plowman London SW
To e-mail, change noise into sound.

In article .com,
Dave wrote:
I have been disappointed with the audio quality of some CDs I have
bought recently. Is there a free program I can use to get an accepted
measurement of fidelity? (like a signal to noise ratio)

I have my suspicious that some may have been stored an MP3s and then
"unripped" in the factory. So how can I tell for certain if my CD has
been an MP3, or other lossy format? I'd hope mp3 storage would leave
different markers than the original tape, for example.

To get a good measure I'd expect some Fourier transforms and signal
analysis to be done, so this should be relevant to sci.physics.

I'd be most surprised if any commercial CD used MP3 or any other lossy
format at any stage of its production. Indeed they mostly use a rather
higher sampling rate etc in production to allow easier signal processing -
eq and compression, etc. But non of that stops the end product sounding
crap if that's what the record company wants. And they frequently do.

--
*TEAMWORK...means never having to take all the blame yourself *

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave" wrote in message
oups.com...
Snipped

I have listened to plenty of CD (about 650), so I think I can tell a
good recording from a bad one. There may be problems of course with
quantative measurement, in that the recording could be done to get the
measurement
high, and it could just sound clinical.

The point was that if I thought a CD sounded poor quality I think
there should be a computer program to confirm this, instead of just
asking someone else.

That's like asking if there's a computer program to confirm a wine is of
poor quality, or a piece of art work is of poor quality. Quality is
subjective, is a composite of many individual factors and can't be reduced
to a number. A computer program (or manual instruments) can analyse the
performance of a piece of music, and give you numbers for dynamic range,
frequency range and by analysing the gaps between music, the background
noise level. It can't then tell you whether this is "good" or "bad" as these
are value judgements.

As to your OP, I think you are asking for a piece of (free) software that
will analyse for any "footprint" left behind by MP3 compression. I have
never come across any such software, free or otherwise, nor do I know of any
reliable way of telling subjectively that something has been (or even is)
MP3 processed, if the bit rate used is high enough.

Others have mentioned the infuriating habit today of removing any vestige of
dynamic range from modern mastered CDs, then clipping the result, all in an
attempt to get maximum loudness. I previously posted that the Daily Mail
even, ran an article a week or two ago highlighting this trend. However, it
is not all the fault of the producers foisting their ideas on the poor
artists, even some artists insist that their CDs are mastered as loud as
possible, as a part of their "sound". Lily Allen was mentioned by name.
This, I think, is much more likely to be the reason for dissatisfaction with
recently mastered CDs than any (unlikely) possibility that MP3 was involved.
As a consequence, I now don't buy any CD that was mastered (or remastered)
in the past 10-12 years.

S.

--
http://audiopages.googlepages.com

"Dave" wrote in message
oups.com...
On 23 Jun, 06:44, "Colin B." wrote:
In rec.audio.tech Dave wrote:

I have been disappointed with the audio quality of some CDs I have
bought recently. Is there a free program I can use to get an accepted
measurement of fidelity? (like a signal to noise ratio)

I have my suspicious that some may have been stored an MP3s and then
"unripped" in the factory. So how can I tell for certain if my CD has
been an MP3, or other lossy format? I'd hope mp3 storage would leave
different markers than the original tape, for example.

Unless these are pirated copies, the answer is most likely not. That's
too much pointless effort for commercial studios to go through.

The answer is much more mundane: Most recording sucks.
Maybe I should retrain when I get to 50 because by then all younger
sound engineers will have grown up with MP3s and not have a clue what
decent audio sounds like.

This is all too true. How many young "sound engineers" today ever get to
mike up a drum kit, or piano these days. How many ever get to record even a
string quartet let alone a full symphony orchestra with a crossed pair of
mics? They may do it as part of a college course, but then never get to
practice once they get out in the world.

S.

--
http://audiopages.googlepages.com

Dave wrote:
I have been disappointed with the audio quality of some CDs I have
bought recently. Is there a free program I can use to get an accepted
measurement of fidelity? (like a signal to noise ratio)

I have my suspicious that some may have been stored an MP3s and then
"unripped" in the factory. So how can I tell for certain if my CD has
been an MP3, or other lossy format? I'd hope mp3 storage would leave
different markers than the original tape, for example.

To get a good measure I'd expect some Fourier transforms and signal
analysis to be done, so this should be relevant to sci.physics.

Which CDs? Perhaps someone else has them and can comment.

--
Eiron.

"Serge Auckland" wrote in message
...

As to your OP, I think you are asking for a piece of (free) software that
will analyse for any "footprint" left behind by MP3 compression. I have
never come across any such software, free or otherwise

Well, you could look for a 15.8kHz hard bandlimit on the audio using the
frequency analyzer in a DAW. That would indicate the likelihood that a
128kbps .mp3 was part of the chain. It's still pretty unlikely, though,
unless the recording is something like a live gig issued by the band itself,
perhaps from a portable .mp3 recorder.

Not impossible, though. Hey, I once co-produced and mastered an album from a
hodgepodge of sources, and one track on it was from MiniDisc, which uses
perceptual-coding algorithms not too conceptually different from those in
the .mp3 format. It's Art Thieme's "The Older I Get, The Better I Was" on
Waterbug. I'd be surprised if someone can tell me which track it was by ear
(no cheating and looking at the liner notes!)

Peace,
Paul

"Dave" wrote in message
oups.com

I have been disappointed with the audio quality of some
CDs I have bought recently. Is there a free program I
can use to get an accepted measurement of fidelity? (like
a signal to noise ratio)

I have my suspicious that some may have been stored an
MP3s and then "unripped" in the factory. So how can I
tell for certain if my CD has been an MP3, or other lossy
format? I'd hope mp3 storage would leave different
markers than the original tape, for example.

Spectal analysis can give strong evidence. Most MP3 files show signs of a
brickwall low pass filter the audio band - sometimes as low as 15 KHz or
less.

"Dave" wrote in message
oups.com...
I have been disappointed with the audio quality of some CDs I have
bought recently.


No surprise there, but let's not get into all of that.....


Is there a free program I can use to get an accepted
measurement of fidelity? (like a signal to noise ratio)


So you can do what - take any disks back to the shop for a refund if a
computer tells you the 'fidelity factor' is below a certain figure
whether you actually *liked* the sound or not....???

"Colin B." wrote


I'd suggest that this isn't a recent phenomenon. I've got plenty of
pop
vinyl from the 1970s and 1980s that has roughly no dynamics.



Yep, you bought it so *they* kept on supplying it - same thing's
happening today, apparently. Where's the problem?


Making crap
sound louder on the radio at the complete expense of quality is
decades old.


Compressed audio like 'Classic FM' on a car radio works very well,
actually....