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Jason
2005-03-31, 14:12
It is entirely possible that you heard something that was not there. If
anything the DAC and clock speeds on the SB2 are more accurate and you
simply might have a preference for the "looser" DAC/clocks in the SB1.

To be taken more seriously it would be better to do a double blind test
where you listen to both players without any knowledge of which player is
running and see if you can still detect the differences you have already
reported.

> -----Original Message-----
> From: discuss-bounces (AT) lists (DOT) slimdevices.com
> [mailto:discuss-bounces (AT) lists (DOT) slimdevices.com] On Behalf Of Ken
> Sent: Thursday, March 31, 2005 1:37 PM
> To: discuss (AT) lists (DOT) slimdevices.com
> Subject: [slim] Squeezebox 2 audio quality.
>
> Sean,
>
> Let me first apologize for the post I made on AudioAsylum. I
> should have taken my thoughts here first and was unaware that
> it would cause a stir. I've asked the folks that run that
> forum to remove my post, and hopefully they will.
>
> The sonic differences we heard are entirely subjective and
> not easily quantifiable, but were easily noticed by all of
> the folks in attendance. Terms such as 'boxy sounding' and
> 'compressed' were used, but there is no way to attach a
> measurable metric to this. I would like to be more specific
> if there are ways you can advise to do so. We were mostly
> just surprised that we heard any differences at all since our
> expectations were that flac vs PCM should yield identical
> results. That all said, I will take time this weekend to
> check through the system setup and make sure that the
> differences we hear aren't due to any other factors.
>
> In the meantime, I've posted a retraction to my comment on
> AudioAsylum to hopefully alleviate any harm it may have done.
> I was naive to think that my comment would be taken in a
> smaller context and the result was certainly not my expectation.
>
> Ken
>
> Sean Adams wrote:
> >
> >> I have and enjoy both my SB1 and the new SB2 I received, but noted
> >> that we could indeed hear audible differences between the
> two types
> >> of streaming. I was (and are still) hoping that this information
> >> would be taken constructively by the Slim Devices folks.
> >
> >
> > Ken,
> >
> > This information is actually not helpful - you need to tell us what
> > you're hearing or give some measurements or a test case which
> > demonstrates an objective difference. Even a subjective
> listening test
> > would be helpful, but only if done scientifically and with
> > double-blind controls.
> >
> > I've got s/pdif and analog audio analyzers, oscilloscopes, spectrum
> > analyzers, function generators, frequency counters, dozens
> of sets of
> > receivers and speakers to test with, and a pair of ears.
> Any problem
> > you can identify could be measured here, but you have to
> tell us what it is.
> >
> > Sean
>
>

Mike Hartley
2005-03-31, 14:50
Jason,
This is an excellent point if this case of SB1 vs SB2. Different does not
necessrily mean bad. But I went back and re-read the post and it seemed to
me that he was saying that they could tell a difference between FLAC
decoding (on the SB2) vs decode to PCM and stream to the SB2 already
uncompressed. If that is the case, the sound should be identical since FLAC
is lossless.

That said, it is entirely possible that double blind testing would reveal no
difference. Listening tests are notoriously unreliable when it comes to
audio equipment, and even when there are differences they are extremely
difficult for listeners to describe in an acccurate and useful manner, just
like Ken said. One interesting example of this is an Extreme Tech test of
Audio Codecs that I read some time ago. A fascinating result of their
listening test was that the higher qulaity variable bit-rate (VBR) files
scored lower with some users than lower quality 128K rips, and that lossless
didn't score close to perfect:

"Notice that we also included a WMA9 Lossless score on the VBR table. We
included one such track on each CD, purely out of curiosity. We are able to
prove that this codec, which only achieves a compression ratio of about 2:1
on most musical tracks, is indeed mathematically lossless. It sounds exactly
like the source material and produces an identical spectrum analysis graph,
without fail. This would lead us to believe that the only score it can
receive is a 5.0, right? But when our listeners didn't know what they were
listening to, some of them scored it lower. Psychologists call this the
"Pygmalion Effect," or self-fulfilling prophecy. Our listeners expected to
hear compressed audio tracks and for there to be artifacts, and therefore
couldn't bring themselves (on the whole) the give the lossless compression
track a perfect score. Even though it was a perfect reproduction, they
scored it as less than such because that is what they expected to hear".
More here if you are interested:
http://www.extremetech.com/article2/0,1558,1560792,00.asp

Mike
----- Original Message -----
From: "Jason" <jason (AT) pagefamily (DOT) net>
To: "'Slim Devices Discussion'" <discuss (AT) lists (DOT) slimdevices.com>
Sent: Thursday, March 31, 2005 4:12 PM
Subject: [slim] Squeezebox 2 audio quality.


> It is entirely possible that you heard something that was not there. If
> anything the DAC and clock speeds on the SB2 are more accurate and you
> simply might have a preference for the "looser" DAC/clocks in the SB1.
>
> To be taken more seriously it would be better to do a double blind test
> where you listen to both players without any knowledge of which player is
> running and see if you can still detect the differences you have already
> reported.
>
> > -----Original Message-----
> > From: discuss-bounces (AT) lists (DOT) slimdevices.com
> > [mailto:discuss-bounces (AT) lists (DOT) slimdevices.com] On Behalf Of Ken
> > Sent: Thursday, March 31, 2005 1:37 PM
> > To: discuss (AT) lists (DOT) slimdevices.com
> > Subject: [slim] Squeezebox 2 audio quality.
> >
> > Sean,
> >
> > Let me first apologize for the post I made on AudioAsylum. I
> > should have taken my thoughts here first and was unaware that
> > it would cause a stir. I've asked the folks that run that
> > forum to remove my post, and hopefully they will.
> >
> > The sonic differences we heard are entirely subjective and
> > not easily quantifiable, but were easily noticed by all of
> > the folks in attendance. Terms such as 'boxy sounding' and
> > 'compressed' were used, but there is no way to attach a
> > measurable metric to this. I would like to be more specific
> > if there are ways you can advise to do so. We were mostly
> > just surprised that we heard any differences at all since our
> > expectations were that flac vs PCM should yield identical
> > results. That all said, I will take time this weekend to
> > check through the system setup and make sure that the
> > differences we hear aren't due to any other factors.
> >
> > In the meantime, I've posted a retraction to my comment on
> > AudioAsylum to hopefully alleviate any harm it may have done.
> > I was naive to think that my comment would be taken in a
> > smaller context and the result was certainly not my expectation.
> >
> > Ken
> >
> > Sean Adams wrote:
> > >
> > >> I have and enjoy both my SB1 and the new SB2 I received, but noted
> > >> that we could indeed hear audible differences between the
> > two types
> > >> of streaming. I was (and are still) hoping that this information
> > >> would be taken constructively by the Slim Devices folks.
> > >
> > >
> > > Ken,
> > >
> > > This information is actually not helpful - you need to tell us what
> > > you're hearing or give some measurements or a test case which
> > > demonstrates an objective difference. Even a subjective
> > listening test
> > > would be helpful, but only if done scientifically and with
> > > double-blind controls.
> > >
> > > I've got s/pdif and analog audio analyzers, oscilloscopes, spectrum
> > > analyzers, function generators, frequency counters, dozens
> > of sets of
> > > receivers and speakers to test with, and a pair of ears.
> > Any problem
> > > you can identify could be measured here, but you have to
> > tell us what it is.
> > >
> > > Sean
> >
> >

Robin Bowes
2005-03-31, 15:04
Mike Hartley wrote:
> If that is the case, the sound should be identical since FLAC
> is lossless.

Not so. There is a possibility that the timing (i.e. clock rate) is
different between flac and PCM. That's pure speculation, but I'm just
pointing out that just getting the bits the same doesn't mean the sound
will be the same.

R.
--
http://robinbowes.com