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John Gresty
2004-07-16, 12:49
I'm a brand new user and extremely impressed with the Squeezebox - great work Slim Devices, et al!

I have a question relating to sample rates for coax digital output from the device. Briefly, my hi-fi DAC doesn't appear to be receiving a 44.1kHz sample signal from the Squeezebox's digital coax output and am looking for help or comments.

In detail... I used EAC software to create uncompressed WAV files of some of my CD collection on my PC (Windows XP). My PC connects via the SlimServer software over an 11mbps wireless network connection to the Squeezebox and then I use the coax digital output to connect to a hi-fi DAC. The DAC I use is aging a bit - it's a Meridian 200 Sigma Delta - but sounds pretty good from my hi-fi CD transport. Previous experimentation with other digital devices led me to call the manufacturer of the DAC, and they claim that it supports both 44.1 and 48kHz sampling. However, when the Squeezebox feeds the DAC with a WAV source, the 44.1kHz LED indicator on the DAC doesn't light up. In fact, I tried a VBR WMA file and found the same result. Interestingly, playing music files (or Internet radio) encoded to MP3 format enables the DAC to lock at 44.1kHz. Before you ask - the DAC doesn't have a 48kHz LED indicator! The main reason I ask is that I believe I can detect a degradation in sound quality and wonder whether some intermediary "upsampling" is taking place somewhere? The SlimServer option for file formats is set to WAV file format, WAV stream format, built-in encoder. I have fixed the digital/output volume. I've played around with EAC and LAME (and APE format) quite a bit, and am reasonably sure I've ripped the music files correctly.

Sorry to be so long-winded - thanks for any help on this.

Mark Bennett
2004-07-16, 13:50
Which version of SlimServer and Squeezebox firmware are you using?
There were some problems with sample rates etc. earlier in the year,
but these have all been fixed as far as I am aware.

Several people with very accurate measuring equipment have verified
the sample rate on the digital out.

Interestingly, I have seen exactly the same behaviour on a very
high-end DAC (Audio Synthesis DAX) even though my personal DAC
(Benchmark DAC-1) works perfectly.

In summary - make sure you're using the latest firmware. If you are,
then you're a member of a very select club whose DAC's just don't
work with the Squeezebox for uncompressed audio streams, and no-one
knows why.

Hopefully another example of thsi behaviour might make it easier to
find the cause, and therefore a solution.....

John Gresty wrote:
> I'm a brand new user and extremely impressed with the Squeezebox - great
> work Slim Devices, et al!
>
> I have a question relating to sample rates for coax digital output from
> the device. Briefly, my hi-fi DAC doesn't appear to be receiving
> a 44.1kHz sample signal from the Squeezebox's digital coax output and am
> looking for help or comments.
>
> In detail... I used EAC software to create uncompressed WAV files of
> some of my CD collection on my PC (Windows XP). My PC connects via the
> SlimServer software over an 11mbps wireless network connection to the
> Squeezebox and then I use the coax digital output to connect to a hi-fi
> DAC. The DAC I use is aging a bit - it's a Meridian 200 Sigma Delta -
> but sounds pretty good from my hi-fi CD transport. Previous
> experimentation with other digital devices led me to call the
> manufacturer of the DAC, and they claim that it supports both 44.1 and
> 48kHz sampling. However, when the Squeezebox feeds the DAC with a WAV
> source, the 44.1kHz LED indicator on the DAC doesn't light up. In fact,
> I tried a VBR WMA file and found the same result. Interestingly,
> playing music files (or Internet radio) encoded to MP3 format enables
> the DAC to lock at 44.1kHz. Before you ask - the DAC doesn't have a
> 48kHz LED indicator! The main reason I ask is that I believe I can
> detect a degradation in sound quality and wonder whether some
> intermediary "upsampling" is taking place somewhere? The SlimServer
> option for file formats is set to WAV file format, WAV stream format,
> built-in encoder. I have fixed the digital/output volume. I've played
> around with EAC and LAME (and APE format) quite a bit, and am reasonably
> sure I've ripped the music files correctly.
>
> Sorry to be so long-winded - thanks for any help on this.
>
>
> ------------------------------------------------------------------------
>
>

Michel Fombellida
2004-07-16, 14:02
Look at my bug report #416. I notice that the digital output can still take
some time to stabilize at 44.10.

Michel

John Gresty
2004-07-17, 03:18
Thanks for the response - I'm using SlimServer 5.2.1 and firmware version 29
for the Squeezebox. Since the 44.1kHz signal locks immediately when I play
MP3 encoded files, I can be sure that the Squeezebox is able to provide a
signal that my DAC is happy with. I wondered whether I might be using
incorrect EAC options for recording WAVs, but I've tried a number of
different recording settings with no joy. The fact that WMA won't lock at
44.1kHz either baffles me. I'm also trembling at the idea of re-recording
my music collection.

With respect to bug report #416, how long is the delay before the 44.1kHz
signal is locked to? I can play a whole album, some tracks > 5 minutes
each, without achieving a lock.

This may be an excuse for a hi-fi upgrade. Time to be extra nice to the
wife ;)

----- Original Message -----
From: "Mark Bennett" <mark (AT) markandliz (DOT) co.uk>
To: "Slim Devices Discussion" <discuss (AT) lists (DOT) slimdevices.com>
Sent: Friday, July 16, 2004 9:50 PM
Subject: [slim] Squeezebox PCM sample rate support


> Which version of SlimServer and Squeezebox firmware are you using?
> There were some problems with sample rates etc. earlier in the year,
> but these have all been fixed as far as I am aware.
>
> Several people with very accurate measuring equipment have verified
> the sample rate on the digital out.
>
> Interestingly, I have seen exactly the same behaviour on a very
> high-end DAC (Audio Synthesis DAX) even though my personal DAC
> (Benchmark DAC-1) works perfectly.
>
> In summary - make sure you're using the latest firmware. If you are,
> then you're a member of a very select club whose DAC's just don't
> work with the Squeezebox for uncompressed audio streams, and no-one
> knows why.
>
> Hopefully another example of thsi behaviour might make it easier to
> find the cause, and therefore a solution.....
>
> John Gresty wrote:
> > I'm a brand new user and extremely impressed with the Squeezebox - great
> > work Slim Devices, et al!
> >
> > I have a question relating to sample rates for coax digital output from
> > the device. Briefly, my hi-fi DAC doesn't appear to be receiving
> > a 44.1kHz sample signal from the Squeezebox's digital coax output and am
> > looking for help or comments.
> >
> > In detail... I used EAC software to create uncompressed WAV files of
> > some of my CD collection on my PC (Windows XP). My PC connects via the
> > SlimServer software over an 11mbps wireless network connection to the
> > Squeezebox and then I use the coax digital output to connect to a hi-fi
> > DAC. The DAC I use is aging a bit - it's a Meridian 200 Sigma Delta -
> > but sounds pretty good from my hi-fi CD transport. Previous
> > experimentation with other digital devices led me to call the
> > manufacturer of the DAC, and they claim that it supports both 44.1 and
> > 48kHz sampling. However, when the Squeezebox feeds the DAC with a WAV
> > source, the 44.1kHz LED indicator on the DAC doesn't light up. In fact,
> > I tried a VBR WMA file and found the same result. Interestingly,
> > playing music files (or Internet radio) encoded to MP3 format enables
> > the DAC to lock at 44.1kHz. Before you ask - the DAC doesn't have a
> > 48kHz LED indicator! The main reason I ask is that I believe I can
> > detect a degradation in sound quality and wonder whether some
> > intermediary "upsampling" is taking place somewhere? The SlimServer
> > option for file formats is set to WAV file format, WAV stream format,
> > built-in encoder. I have fixed the digital/output volume. I've played
> > around with EAC and LAME (and APE format) quite a bit, and am reasonably
> > sure I've ripped the music files correctly.
> >
> > Sorry to be so long-winded - thanks for any help on this.
> >
> >
> > ------------------------------------------------------------------------
> >
> >

Mark Bennett
2004-07-17, 03:51
John,

Ok, since you're using the lates official version of the software,
it looks like you should have all the firmware bug fixes that we
know about for the digital outs.

When I said I saw exactly the same symptoms, I meant it. MP3
music, which streams as MP3 and is decoded in the Squeezebox
itself worked perfectly.

Any other form of coding, which is converted on the server
side and streamed as WAV, did not work on this one particular
(old & high-end) DAC. However it does work on my own DAC (which
is obviously not so fussy).

Adding the flac decoder into the Squeezebox has been discussed
a few times, and apparently looks to be feasible, and may
inadvertantly fix the problem. (The aim of this is to reduce
the network bandwidth required and to increase the effective
buffer length.) However, it's not clear that this is currently
actively being worked on, or if it is still something for us
audiophiles to dream about.

One last thought - have you tried both co-ax and optical
digital outs? In my case it didn't make any difference, but if
you have the cables handy to try it it might be worth a go.

Cheers,
Mark.


John Gresty wrote:
> Thanks for the response - I'm using SlimServer 5.2.1 and firmware version 29
> for the Squeezebox. Since the 44.1kHz signal locks immediately when I play
> MP3 encoded files, I can be sure that the Squeezebox is able to provide a
> signal that my DAC is happy with. I wondered whether I might be using
> incorrect EAC options for recording WAVs, but I've tried a number of
> different recording settings with no joy. The fact that WMA won't lock at
> 44.1kHz either baffles me. I'm also trembling at the idea of re-recording
> my music collection.
>
> With respect to bug report #416, how long is the delay before the 44.1kHz
> signal is locked to? I can play a whole album, some tracks > 5 minutes
> each, without achieving a lock.
>
> This may be an excuse for a hi-fi upgrade. Time to be extra nice to the
> wife ;)
>
> ----- Original Message -----
> From: "Mark Bennett" <mark (AT) markandliz (DOT) co.uk>
> To: "Slim Devices Discussion" <discuss (AT) lists (DOT) slimdevices.com>
> Sent: Friday, July 16, 2004 9:50 PM
> Subject: [slim] Squeezebox PCM sample rate support
>
>
>
>>Which version of SlimServer and Squeezebox firmware are you using?
>>There were some problems with sample rates etc. earlier in the year,
>>but these have all been fixed as far as I am aware.
>>
>>Several people with very accurate measuring equipment have verified
>>the sample rate on the digital out.
>>
>>Interestingly, I have seen exactly the same behaviour on a very
>>high-end DAC (Audio Synthesis DAX) even though my personal DAC
>>(Benchmark DAC-1) works perfectly.
>>
>>In summary - make sure you're using the latest firmware. If you are,
>>then you're a member of a very select club whose DAC's just don't
>>work with the Squeezebox for uncompressed audio streams, and no-one
>>knows why.
>>
>>Hopefully another example of thsi behaviour might make it easier to
>>find the cause, and therefore a solution.....
>>
>>John Gresty wrote:
>>
>>>I'm a brand new user and extremely impressed with the Squeezebox - great
>>>work Slim Devices, et al!
>>>
>>>I have a question relating to sample rates for coax digital output from
>>>the device. Briefly, my hi-fi DAC doesn't appear to be receiving
>>>a 44.1kHz sample signal from the Squeezebox's digital coax output and am
>>>looking for help or comments.
>>>
>>>In detail... I used EAC software to create uncompressed WAV files of
>>>some of my CD collection on my PC (Windows XP). My PC connects via the
>>>SlimServer software over an 11mbps wireless network connection to the
>>>Squeezebox and then I use the coax digital output to connect to a hi-fi
>>>DAC. The DAC I use is aging a bit - it's a Meridian 200 Sigma Delta -
>>>but sounds pretty good from my hi-fi CD transport. Previous
>>>experimentation with other digital devices led me to call the
>>>manufacturer of the DAC, and they claim that it supports both 44.1 and
>>>48kHz sampling. However, when the Squeezebox feeds the DAC with a WAV
>>>source, the 44.1kHz LED indicator on the DAC doesn't light up. In fact,
>>>I tried a VBR WMA file and found the same result. Interestingly,
>>>playing music files (or Internet radio) encoded to MP3 format enables
>>>the DAC to lock at 44.1kHz. Before you ask - the DAC doesn't have a
>>>48kHz LED indicator! The main reason I ask is that I believe I can
>>>detect a degradation in sound quality and wonder whether some
>>>intermediary "upsampling" is taking place somewhere? The SlimServer
>>>option for file formats is set to WAV file format, WAV stream format,
>>>built-in encoder. I have fixed the digital/output volume. I've played
>>>around with EAC and LAME (and APE format) quite a bit, and am reasonably
>>>sure I've ripped the music files correctly.
>>>
>>>Sorry to be so long-winded - thanks for any help on this.
>>>
>>>
>>>------------------------------------------------------------------------
>>>
>>>

John Gresty
2004-07-17, 04:52
Mark,

Thanks once again for the response. Yes - it sounds like exactly the same
symptoms. My DAC doesn't have an optical input, but I have an off-board
device made by a manufacturer called CO2 for performing optical to digital
signal conversion. However, just as you found on the particular DAC, I'm
still not getting a 44.1kHz lock. Oh well...

I haven't looked up the old on-board flac converter debate, but will listen
with interest for future developments. I suppose with increasing bandwidth
support in new networking devices this is going to be less and less of a
priority though.

Thanks again for your input - finding another example of the same problem at
least keeps me sane!

JohnG.


----- Original Message -----
From: "Mark Bennett" <mark (AT) markandliz (DOT) co.uk>
To: "Slim Devices Discussion" <discuss (AT) lists (DOT) slimdevices.com>
Sent: Saturday, July 17, 2004 11:51 AM
Subject: [slim] Squeezebox PCM sample rate support


> John,
>
> Ok, since you're using the lates official version of the software,
> it looks like you should have all the firmware bug fixes that we
> know about for the digital outs.
>
> When I said I saw exactly the same symptoms, I meant it. MP3
> music, which streams as MP3 and is decoded in the Squeezebox
> itself worked perfectly.
>
> Any other form of coding, which is converted on the server
> side and streamed as WAV, did not work on this one particular
> (old & high-end) DAC. However it does work on my own DAC (which
> is obviously not so fussy).
>
> Adding the flac decoder into the Squeezebox has been discussed
> a few times, and apparently looks to be feasible, and may
> inadvertantly fix the problem. (The aim of this is to reduce
> the network bandwidth required and to increase the effective
> buffer length.) However, it's not clear that this is currently
> actively being worked on, or if it is still something for us
> audiophiles to dream about.
>
> One last thought - have you tried both co-ax and optical
> digital outs? In my case it didn't make any difference, but if
> you have the cables handy to try it it might be worth a go.
>
> Cheers,
> Mark.
>
>
> John Gresty wrote:
> > Thanks for the response - I'm using SlimServer 5.2.1 and firmware
version 29
> > for the Squeezebox. Since the 44.1kHz signal locks immediately when I
play
> > MP3 encoded files, I can be sure that the Squeezebox is able to provide
a
> > signal that my DAC is happy with. I wondered whether I might be using
> > incorrect EAC options for recording WAVs, but I've tried a number of
> > different recording settings with no joy. The fact that WMA won't lock
at
> > 44.1kHz either baffles me. I'm also trembling at the idea of
re-recording
> > my music collection.
> >
> > With respect to bug report #416, how long is the delay before the
44.1kHz
> > signal is locked to? I can play a whole album, some tracks > 5 minutes
> > each, without achieving a lock.
> >
> > This may be an excuse for a hi-fi upgrade. Time to be extra nice to the
> > wife ;)
> >
> > ----- Original Message -----
> > From: "Mark Bennett" <mark (AT) markandliz (DOT) co.uk>
> > To: "Slim Devices Discussion" <discuss (AT) lists (DOT) slimdevices.com>
> > Sent: Friday, July 16, 2004 9:50 PM
> > Subject: [slim] Squeezebox PCM sample rate support
> >
> >
> >
> >>Which version of SlimServer and Squeezebox firmware are you using?
> >>There were some problems with sample rates etc. earlier in the year,
> >>but these have all been fixed as far as I am aware.
> >>
> >>Several people with very accurate measuring equipment have verified
> >>the sample rate on the digital out.
> >>
> >>Interestingly, I have seen exactly the same behaviour on a very
> >>high-end DAC (Audio Synthesis DAX) even though my personal DAC
> >>(Benchmark DAC-1) works perfectly.
> >>
> >>In summary - make sure you're using the latest firmware. If you are,
> >>then you're a member of a very select club whose DAC's just don't
> >>work with the Squeezebox for uncompressed audio streams, and no-one
> >>knows why.
> >>
> >>Hopefully another example of thsi behaviour might make it easier to
> >>find the cause, and therefore a solution.....
> >>
> >>John Gresty wrote:
> >>
> >>>I'm a brand new user and extremely impressed with the Squeezebox -
great
> >>>work Slim Devices, et al!
> >>>
> >>>I have a question relating to sample rates for coax digital output from
> >>>the device. Briefly, my hi-fi DAC doesn't appear to be receiving
> >>>a 44.1kHz sample signal from the Squeezebox's digital coax output and
am
> >>>looking for help or comments.
> >>>
> >>>In detail... I used EAC software to create uncompressed WAV files of
> >>>some of my CD collection on my PC (Windows XP). My PC connects via the
> >>>SlimServer software over an 11mbps wireless network connection to the
> >>>Squeezebox and then I use the coax digital output to connect to a hi-fi
> >>>DAC. The DAC I use is aging a bit - it's a Meridian 200 Sigma Delta -
> >>>but sounds pretty good from my hi-fi CD transport. Previous
> >>>experimentation with other digital devices led me to call the
> >>>manufacturer of the DAC, and they claim that it supports both 44.1 and
> >>>48kHz sampling. However, when the Squeezebox feeds the DAC with a WAV
> >>>source, the 44.1kHz LED indicator on the DAC doesn't light up. In
fact,
> >>>I tried a VBR WMA file and found the same result. Interestingly,
> >>>playing music files (or Internet radio) encoded to MP3 format enables
> >>>the DAC to lock at 44.1kHz. Before you ask - the DAC doesn't have a
> >>>48kHz LED indicator! The main reason I ask is that I believe I can
> >>>detect a degradation in sound quality and wonder whether some
> >>>intermediary "upsampling" is taking place somewhere? The SlimServer
> >>>option for file formats is set to WAV file format, WAV stream format,
> >>>built-in encoder. I have fixed the digital/output volume. I've played
> >>>around with EAC and LAME (and APE format) quite a bit, and am
reasonably
> >>>sure I've ripped the music files correctly.
> >>>
> >>>Sorry to be so long-winded - thanks for any help on this.
> >>>
> >>>
>
>>>------------------------------------------------------------------------
> >>>
> >>>

Michel Fombellida
2004-07-17, 10:59
Hi,

> With respect to bug report #416, how long is the delay before the 44.1kHz
> signal is locked to?

In my case I see the clock frequency drifting for about 15 seconds. I noticed
that pausing the SB during this drift sometimes help the DAC to lock. Once it
the DAC is locked, the SB can be unpaused.

Michel

John Gresty
2004-07-17, 14:35
I've now tried your suggestion of pausing the SB, but unfortunately this
doesn't help my DAC to gain 44.1kHz lock. Thanks for the suggestion though
Michel.

Since Mark's suggestion regarding switching to optical I've noticed
something (mildly) interesting. In order to switch to optical, I have to
pass the signal through a CO2 optical-to-digital converter - as described
previously in this thread. When I do this, I still can't get 44.1kHz lock
and the lock light remains firmly off on the DAC. In order to try Michel's
idea, I switched back to a direct digital signal from the Squeezebox and
noticed that the 44.1kHz lock light on the DAC becomes "dimly lit". On very
close-up inspection, the light is actually flickering at incredibly high
speed. I'm not sure this means anything - and am happy to accept that my
DAC is just too fussy for the Squeezebox - but thought it was worth
mentioning. I wouldn't want to stake my life to a blind listening test, but
I believe sound quality is better when the lock light isn't flickering.

Finally, I should correct a detail I mentioned at the start of this thread
in case it proves useful to anyone in future. The DAC is a Meridian 263
Sigma Delta, not a 200 as previously reported (200 is the CD transport model
number).

JohnG.

----- Original Message -----
From: "Michel Fombellida" <mf22433 (AT) yahoo (DOT) com>
To: <discuss (AT) lists (DOT) slimdevices.com>
Sent: Saturday, July 17, 2004 6:59 PM
Subject: [slim] Squeezebox PCM sample rate support


> Hi,
>
> > With respect to bug report #416, how long is the delay before the
44.1kHz
> > signal is locked to?
>
> In my case I see the clock frequency drifting for about 15 seconds. I
noticed
> that pausing the SB during this drift sometimes help the DAC to lock. Once
it
> the DAC is locked, the SB can be unpaused.
>
> Michel
>
>
>