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Demo material recommendation

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Anonymous
July 24, 2005 11:00:22 PM

Archived from groups: rec.audio.high-end (More info?)

I've performed an experiment with surprising results. The object of this
experiment was to evaluate lossy compression codecs. I decided to use an
excellent piano recording of a couple of Rachmaninoff preludes as the
material. I ripped these pieces to wav files, and converted the wave files
to each of 5 different codecs:

LAME mp3 at 256kb/s, for a 5:1 compression ratio
LAME mp3 at 128kb/s, for 10:1
WMA9 at 64kb/s, for 21:1
WMA9 at 32kb/s, for 42:1
WMA9 VBR10, for 50:1

The VBR10 variable bit rate file was the smallest one that could be
converted back to wav and subsequently burned to a CDR. This is what I did,
putting all 5 compressed versions and the original wav file on the CDR in
random order. I made 6 copies of this disc and passed them around to
discriminating friends, with instructions to rate the fidelity of each file,
and rank them in order. I didn't tell them what they should be listening
for. All these friends have excellent audio systems, in one case costing
over $40,000.

So far, 2 people have returned their discs with their comments. Neither of
them chose the original wav track as the best; neither chose the WMA VBR
file as the worst, inspite of its 50 to 1 compression ratio!

I'd like to expand this test to music having a wider dynamic and frequency
range. I'd like some suggestions from the group of a classical selection
running about 3 minutes that might be more revealing of codec differences
than piano music. Try to pick something fairly easy to locate, and
preferably a piece generally regarded as a great recording. I'll then
rerun this test with the new material. Hopefully, the degradation of the
highly compressed files will be easier to pick out.

Thanks for your input,

Norm Strong
July 25, 2005 5:01:26 AM

Archived from groups: rec.audio.high-end (More info?)

normanstrong@comcast.net wrote:

> I've performed an experiment with surprising results. The object of this
> experiment was to evaluate lossy compression codecs. I decided to use an
> excellent piano recording of a couple of Rachmaninoff preludes as the
> material. I ripped these pieces to wav files, and converted the wave files
> to each of 5 different codecs:
>
> LAME mp3 at 256kb/s, for a 5:1 compression ratio
> LAME mp3 at 128kb/s, for 10:1
> WMA9 at 64kb/s, for 21:1
> WMA9 at 32kb/s, for 42:1
> WMA9 VBR10, for 50:1
>
> The VBR10 variable bit rate file was the smallest one that could be
> converted back to wav and subsequently burned to a CDR. This is what I did,
> putting all 5 compressed versions and the original wav file on the CDR in
> random order. I made 6 copies of this disc and passed them around to
> discriminating friends, with instructions to rate the fidelity of each file,
> and rank them in order. I didn't tell them what they should be listening
> for. All these friends have excellent audio systems, in one case costing
> over $40,000.
>
> So far, 2 people have returned their discs with their comments. Neither of
> them chose the original wav track as the best; neither chose the WMA VBR
> file as the worst, inspite of its 50 to 1 compression ratio!
>
> I'd like to expand this test to music having a wider dynamic and frequency
> range. I'd like some suggestions from the group of a classical selection
> running about 3 minutes that might be more revealing of codec differences
> than piano music. Try to pick something fairly easy to locate, and
> preferably a piece generally regarded as a great recording. I'll then
> rerun this test with the new material. Hopefully, the degradation of the
> highly compressed files will be easier to pick out.
>
> Thanks for your input,
>
> Norm Strong
>

I have found certain piano solos to require high bitrates in order to
sound good. Here are a couple of tracks you can try out, Certainly these
are common enough so that you should find them in your local library:

1. Glenn Gould's Bach Two-Part Inventions and Three-Part Sinfonias.
Sony Classical, SMK-52596. Track 1.

2. Glenn Gould's Goldberg Variations (the first recording). Track 1
(Aria). I have the Sony State of Wonder CD set.

I find that Gould's clean playing style and miminal use of the sustain
pedal somehow make it easier to tell the difference between mp3's and
the original.
Anonymous
July 25, 2005 5:01:44 AM

Archived from groups: rec.audio.high-end (More info?)

normanstrong@comcast.net wrote:
> I've performed an experiment with surprising results. The object of this
> experiment was to evaluate lossy compression codecs. I decided to use an
> excellent piano recording of a couple of Rachmaninoff preludes as the
> material. I ripped these pieces to wav files, and converted the wave files
> to each of 5 different codecs:

> LAME mp3 at 256kb/s, for a 5:1 compression ratio
> LAME mp3 at 128kb/s, for 10:1
> WMA9 at 64kb/s, for 21:1
> WMA9 at 32kb/s, for 42:1
> WMA9 VBR10, for 50:1

> The VBR10 variable bit rate file was the smallest one that could be
> converted back to wav and subsequently burned to a CDR. This is what I did,
> putting all 5 compressed versions and the original wav file on the CDR in
> random order. I made 6 copies of this disc and passed them around to
> discriminating friends, with instructions to rate the fidelity of each file,
> and rank them in order. I didn't tell them what they should be listening
> for. All these friends have excellent audio systems, in one case costing
> over $40,000.

> So far, 2 people have returned their discs with their comments. Neither of
> them chose the original wav track as the best; neither chose the WMA VBR
> file as the worst, inspite of its 50 to 1 compression ratio!

> I'd like to expand this test to music having a wider dynamic and frequency
> range. I'd like some suggestions from the group of a classical selection
> running about 3 minutes that might be more revealing of codec differences
> than piano music. Try to pick something fairly easy to locate, and
> preferably a piece generally regarded as a great recording. I'll then
> rerun this test with the new material. Hopefully, the degradation of the
> highly compressed files will be easier to pick out.

difficult-to-encode music for codec testing:


http://ff123.net/samples.html
Related resources
July 26, 2005 4:39:57 AM

Archived from groups: rec.audio.high-end (More info?)

In article <dc1dl609q4@news4.newsguy.com>, Chung <chunglau@covad.net>
wrote:

> normanstrong@comcast.net wrote:
>
> > I've performed an experiment with surprising results. The object of this
> > experiment was to evaluate lossy compression codecs. I decided to use an
> > excellent piano recording of a couple of Rachmaninoff preludes as the
> > material. I ripped these pieces to wav files, and converted the wave files
> > to each of 5 different codecs:
> >
> > LAME mp3 at 256kb/s, for a 5:1 compression ratio
> > LAME mp3 at 128kb/s, for 10:1
> > WMA9 at 64kb/s, for 21:1
> > WMA9 at 32kb/s, for 42:1
> > WMA9 VBR10, for 50:1
> >
> > The VBR10 variable bit rate file was the smallest one that could be
> > converted back to wav and subsequently burned to a CDR. This is what I
> > did,
> > putting all 5 compressed versions and the original wav file on the CDR in
> > random order. I made 6 copies of this disc and passed them around to
> > discriminating friends, with instructions to rate the fidelity of each
> > file,
> > and rank them in order. I didn't tell them what they should be listening
> > for. All these friends have excellent audio systems, in one case costing
> > over $40,000.
> >
> > So far, 2 people have returned their discs with their comments. Neither of
> > them chose the original wav track as the best; neither chose the WMA VBR
> > file as the worst, inspite of its 50 to 1 compression ratio!
> >
> > I'd like to expand this test to music having a wider dynamic and frequency
> > range. I'd like some suggestions from the group of a classical selection
> > running about 3 minutes that might be more revealing of codec differences
> > than piano music. Try to pick something fairly easy to locate, and
> > preferably a piece generally regarded as a great recording. I'll then
> > rerun this test with the new material. Hopefully, the degradation of the
> > highly compressed files will be easier to pick out.
> >
> > Thanks for your input,
> >
> > Norm Strong
> >
>
> I have found certain piano solos to require high bitrates in order to
> sound good. Here are a couple of tracks you can try out, Certainly these
> are common enough so that you should find them in your local library:
>
> 1. Glenn Gould's Bach Two-Part Inventions and Three-Part Sinfonias.
> Sony Classical, SMK-52596. Track 1.
>
> 2. Glenn Gould's Goldberg Variations (the first recording). Track 1
> (Aria). I have the Sony State of Wonder CD set.
>
> I find that Gould's clean playing style and miminal use of the sustain
> pedal somehow make it easier to tell the difference between mp3's and
> the original.

Though I'm generally against using a piano for this literature, GG
certainly did use minimal sustain, which is most appropriate. It bugs
me to no end to hear baroque harpsichord and clavichord lit played on a
Steinway with pedaling. Ugh!

Speaking of piano, I did the Ravel G Major with Jeffrey Kahane this
weekend. WOW! What a great artist, and such a fun work!
July 26, 2005 4:40:50 AM

Archived from groups: rec.audio.high-end (More info?)

normanstrong@comcast.net wrote:
> I've performed an experiment with surprising results. The object of this
> experiment was to evaluate lossy compression codecs. I decided to use an
> excellent piano recording of a couple of Rachmaninoff preludes as the
> material. I ripped these pieces to wav files, and converted the wave files
> to each of 5 different codecs:
>
> LAME mp3 at 256kb/s, for a 5:1 compression ratio
> LAME mp3 at 128kb/s, for 10:1
> WMA9 at 64kb/s, for 21:1
> WMA9 at 32kb/s, for 42:1
> WMA9 VBR10, for 50:1
>
> The VBR10 variable bit rate file was the smallest one that could be
> converted back to wav and subsequently burned to a CDR. This is what I did,
> putting all 5 compressed versions and the original wav file on the CDR in
> random order. I made 6 copies of this disc and passed them around to
> discriminating friends, with instructions to rate the fidelity of each file,
> and rank them in order. I didn't tell them what they should be listening
> for. All these friends have excellent audio systems, in one case costing
> over $40,000.
>
> So far, 2 people have returned their discs with their comments. Neither of
> them chose the original wav track as the best; neither chose the WMA VBR
> file as the worst, inspite of its 50 to 1 compression ratio!
>
> I'd like to expand this test to music having a wider dynamic and frequency
> range. I'd like some suggestions from the group of a classical selection
> running about 3 minutes that might be more revealing of codec differences
> than piano music. Try to pick something fairly easy to locate, and
> preferably a piece generally regarded as a great recording. I'll then
> rerun this test with the new material. Hopefully, the degradation of the
> highly compressed files will be easier to pick out.
>
> Thanks for your input,
>
> Norm Strong
>


The choral piece on the end of the Dorian Sampler I will fit the bill.
Mere regular 'high-end' systems fall apart on the creshendo which
includes a large chorus and orchestra, minimalist mic'ing and
outstanding spatial representation. The resolution and detail falls away
with lesser systems...

_-_-bear

You will not be able to hear substantial differences on instruments -
you need vocals, and best not pure solo voice - layers will show more.
!