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View Full Version : Digital out fails for 64k audio, works for 56k



David Hearst
2004-07-13, 15:49
Dean,

Here's the link for the station:

http://www.live365.com/stations/vongoober?play

Here's the broadcaster's home page as well:

http://www.vongoober.com


I do think this has something to do with the fact that the station is
broadcast as MP3Pro and thus is being handled by the SlimServer and the
Squeezebox as bandwidth constrained MP3. I just can't figure out why the
stream works when the Squeezebox feeds my SuperDAC and not when it feeds my
Marantz receiver. What type of stream would you expect to be delivered at
the Squeezebox's output when it receives incoming MP3 stream? Would it be
PCM data? Would its sample rate and/or bit depth be determined by the
characteristics of the incoming MP3 stream? I'm guessing that whatever
digital format the Squeezebox outputs in response to the incoming MP3Pro is
supported by my SuperDAC but not my receiver. I just don't know if that's
what we'd expect from the Squeezebox.

Thanks for your help,

David



-----Original Message-----
From: discuss-bounces (AT) lists (DOT) slimdevices.com
[mailto:discuss-bounces (AT) lists (DOT) slimdevices.com]On Behalf Of dean
blackketter
Sent: Tuesday, July 13, 2004 2:53 PM
To: Slim Devices Discussion
Subject: [slim] Digital out fails for 64k audio, works for 56k


Can you post the URL for the failing station?

On Jul 9, 2004, at 3:54 PM, David Hearst wrote:

> Sean,
>
> Thanks for the suggestion. I've actually done a bit more
> experimentation and it's pretty clear that the problem is not 32kHz
> sample rate. Here's the additional info:
>
> I own two Squeezeboxes (an early wireless model and a fairly recent
> wired model). One is attached to the optical digital input on our home
> theater receiver, the other is connected to an M-Audio Super DAC 2496.
> After my original E-mail, I discovered that the Squeezebox /SuperDAC
> combo was working fine with the 64k stream. I then confirmed that
> either one of my Squeezeboxes work fine with the SuperDAC. They just
> don't work with my home theater receiver.
>
> To the best of my knowledge, the difference between these internet
> radio stations is as follows:
>
> Success: 56k bit , standard Live365 stream
> Failure: 64k, MP3 Pro-capable Live365 stream
>
> That leads me to a question. I'm just wondering whether you'd expect
> the digital stream coming out of the Squeezebox to be significantly
> different in these two cases and, if so, different in what way?
> Obviously, a simple and not-too-expensive solution would be to
> purchase another SuperDAC to use with our home theater. I'd just like
> to understand what the problem is before jumping on that bandwagon...
>
> Thanks, David
>
>
> On Jul 9, 2004, at 3:03 PM, Sean Adams wrote:
>
>>
>> David,
>>
>> Probably the stream is using a 32KHz sample rate, which is not
>> compatible with s/pdif (not a squeezebox limitation - just not
>> supported over s/pdif at all).
>>
>> The best solution if you have a receiver which auto-senses the s/pdif
>> signal is to connect both cables. Then the amp will automatically
>> fall back to the analog inputs if s/pdif is not available.
>>
>> Sean
>>
>> On Jul 9, 2004, at 11:27 AM, David Hearst wrote:
>>
>>> For quite awhile I've been using my Squeezebox and SlimServer to
>>> deliver Live365 broadcasts to my stereo using the digital (optical)
>>> output. It has worked fine for the stations I used up until now but
>>> it turns out that all of them are being streamed at 56k bit quality
>>> from their respective servers. Today I tried to set up a 64k bit
>>> stream in a similar fashion and found that I get no output from my
>>> stereo. However, if I use the analog outs on the Squeezebox they
>>> work fine. It's just the digital (optical) output that is a problem.
>>> All the 64k stream doesn't work, not only do 56k streams work, but
>>> the WAV audio files in my iTunes library work fine as well when
>>> played through the digital (optical) output.
>>>
>>> Has anyone experienced this? Should the Squeezebox be delivering the
>>> same type of digital signal output regardless of the stream rate
>>> received by the SlimServer? Are there any settings I can change to
>>> overcome this problem?
>>>
>>> Thanks for the help,
>>>
>>> David Hearst
>>> david (AT) madd-dogg (DOT) com
>>>
>>>

dean
2004-07-14, 08:21
Hi David,

I took a look at that station and it appears to use a 22.050k sample
rate, which doesn't work over S/PDIF, according to the spec. Maybe
your SuperDAC is smart enough to be able to play back non-standard
sample rates.


On Jul 13, 2004, at 3:49 PM, David Hearst wrote:

> Dean,
>
> Here's the link for the station:
>
> http://www.live365.com/stations/vongoober?play
>
> Here's the broadcaster's home page as well:
>
> http://www.vongoober.com
>
>
> I do think this has something to do with the fact that the station is
> broadcast as MP3Pro and thus is being handled by the SlimServer and the
> Squeezebox as bandwidth constrained MP3. I just can't figure out why
> the
> stream works when the Squeezebox feeds my SuperDAC and not when it
> feeds my
> Marantz receiver. What type of stream would you expect to be delivered
> at
> the Squeezebox's output when it receives incoming MP3 stream? Would it
> be
> PCM data? Would its sample rate and/or bit depth be determined by the
> characteristics of the incoming MP3 stream? I'm guessing that whatever
> digital format the Squeezebox outputs in response to the incoming
> MP3Pro is
> supported by my SuperDAC but not my receiver. I just don't know if
> that's
> what we'd expect from the Squeezebox.
>
> Thanks for your help,
>
> David
>
>
>
> -----Original Message-----
> From: discuss-bounces (AT) lists (DOT) slimdevices.com
> [mailto:discuss-bounces (AT) lists (DOT) slimdevices.com]On Behalf Of dean
> blackketter
> Sent: Tuesday, July 13, 2004 2:53 PM
> To: Slim Devices Discussion
> Subject: [slim] Digital out fails for 64k audio, works for 56k
>
>
> Can you post the URL for the failing station?
>
> On Jul 9, 2004, at 3:54 PM, David Hearst wrote:
>
>> Sean,
>>
>> Thanks for the suggestion. I've actually done a bit more
>> experimentation and it's pretty clear that the problem is not 32kHz
>> sample rate. Here's the additional info:
>>
>> I own two Squeezeboxes (an early wireless model and a fairly recent
>> wired model). One is attached to the optical digital input on our home
>> theater receiver, the other is connected to an M-Audio Super DAC 2496.
>> After my original E-mail, I discovered that the Squeezebox /SuperDAC
>> combo was working fine with the 64k stream. I then confirmed that
>> either one of my Squeezeboxes work fine with the SuperDAC. They just
>> don't work with my home theater receiver.
>>
>> To the best of my knowledge, the difference between these internet
>> radio stations is as follows:
>>
>> Success: 56k bit , standard Live365 stream
>> Failure: 64k, MP3 Pro-capable Live365 stream
>>
>> That leads me to a question. I'm just wondering whether you'd expect
>> the digital stream coming out of the Squeezebox to be significantly
>> different in these two cases and, if so, different in what way?
>> Obviously, a simple and not-too-expensive solution would be to
>> purchase another SuperDAC to use with our home theater. I'd just like
>> to understand what the problem is before jumping on that bandwagon...
>>
>> Thanks, David
>>
>>
>> On Jul 9, 2004, at 3:03 PM, Sean Adams wrote:
>>
>>>
>>> David,
>>>
>>> Probably the stream is using a 32KHz sample rate, which is not
>>> compatible with s/pdif (not a squeezebox limitation - just not
>>> supported over s/pdif at all).
>>>
>>> The best solution if you have a receiver which auto-senses the s/pdif
>>> signal is to connect both cables. Then the amp will automatically
>>> fall back to the analog inputs if s/pdif is not available.
>>>
>>> Sean
>>>
>>> On Jul 9, 2004, at 11:27 AM, David Hearst wrote:
>>>
>>>> For quite awhile I've been using my Squeezebox and SlimServer to
>>>> deliver Live365 broadcasts to my stereo using the digital (optical)
>>>> output. It has worked fine for the stations I used up until now but
>>>> it turns out that all of them are being streamed at 56k bit quality
>>>> from their respective servers. Today I tried to set up a 64k bit
>>>> stream in a similar fashion and found that I get no output from my
>>>> stereo. However, if I use the analog outs on the Squeezebox they
>>>> work fine. It's just the digital (optical) output that is a problem.
>>>> All the 64k stream doesn't work, not only do 56k streams work, but
>>>> the WAV audio files in my iTunes library work fine as well when
>>>> played through the digital (optical) output.
>>>>
>>>> Has anyone experienced this? Should the Squeezebox be delivering the
>>>> same type of digital signal output regardless of the stream rate
>>>> received by the SlimServer? Are there any settings I can change to
>>>> overcome this problem?
>>>>
>>>> Thanks for the help,
>>>>
>>>> David Hearst
>>>> david (AT) madd-dogg (DOT) com
>>>>
>>>>