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[Grey Friar]

I have been unable to play 88.1 or 176.2 kHz files bit-perfectly in either MC17 or MC20 via the SPDIF header in my HTPC.  The SPDIF connection (galvanically isolated with a 1:1 Pulse transformer) is on an Intel i3 board with Realtek ALC892 audio driver (updated to the latest version) connected via coax to a Musical Fidelity V-DAC II.  I get an error message with 88.1 and 176.2, but 192 kHz files appear to be playing bit-perfectly according to "Audio Path" and the spectrum visualizer -- however, no sound emerges with 192K files.  The output mode is set to WASAPI-Event Style, Exclusive Access. In some cases, with higher frequency files, I must also use the 32-bit package or I get only static.

All files types can be played using Direct Sound output mode, or on the VLC player -- but, of course, the sound is terrible.  Using DSP Studio to resample all files to 96 kHz works fine, but I was hoping for "bit-perfect" playback.  The V-DAC is specified to play all files from 32 t0 192 kHz bit-perfectly.

If I instead use an esi Juli@ PCI soundcard with ASIO drivers feeding its SPDIF output to the V-DAC, every file type plays as intended.  An extra-cost solution, however.

Any suggestions?   Thanks much.

(Please excuse this duplicate post.)

[Grey Friar]

I have been unable to play 88.1 or 176.2 kHz files bit-perfectly in either MC17 or MC20 via the SPDIF header in my HTPC.  The SPDIF connection (galvanically isolated with a 1:1 Pulse transformer) is on an Intel i3 board with Realtek ALC892 audio driver (updated to the latest version) connected via coax to a Musical Fidelity V-DAC II.  I get an error message with 88.1 and 176.2, but 192 kHz files appear to be playing bit-perfectly according to "Audio Path" and the spectrum visualizer -- however, no sound emerges with 192K files.  The output mode is set to WASAPI-Event Style, Exclusive Access. In some cases, with higher frequency files, I must use the 32-bit package or I get only static.

All files types can be played using Direct Sound output mode, or on the VLC player -- but, of course, the sound is not very good.  Using DSP Studio to resample all files to 96 kHz works fine, but I was hoping for "bit-perfect" playback.  The V-DAC is specified to play all files from 32 t0 192 kHz bit-perfectly.

If I instead use an esi Juli@ PCI soundcard with ASIO drivers feeding its SPDIF output to the V-DAC, every file type plays as intended.  An extra-cost solution, however.

Any suggestions?   Thanks much.

[felix2]

While S/PDIF the protocol standard can support up to 24/196, actual bitrate depends on the transmission medium (coax or optical), and on the digital audio processing hardware/driver (sound card) that's driving the S/PDIF output. It also depends on the ability of the receiver - clearly no use to send a 24/96 signal a DAC that does not support support it. Over the years I have used S/PDIF output from a dozen sound cards, coaxial and optical, and every one of them has a different set of supported audio bitrate and encoding. All digital audio transmissions are encoded and therefore each audio processing/transmission system must specifically be designed to support its set of audio encoding method - PCM, Dolby, DTS, etc.. There is no such thing as a 'raw' digital audio. With this in mind, do the following check:

1) Open Control Panel>Sound to see the full set of sound cards, each further listed by type of output port, in your PC. Identify those with S/PDIF output.
2) For each S/PDIF, enter Properties>Supported Formats tab. The bitrate and audio encoded format capability of this card/port combination is revealed.
3) Check those boxes which you want to enable and use. This is just a software turn-on since the full hardware capability is already revealed.

This sets up the Windows side of things, meaning its DirectSound system is now configured for this sound card. BUT if you have additional hardware, such as a DAC that requires special driver in order to do high-res, then you must further install & configure the driver. This driver now controls bitrates and encoding, especially when you used WASAPI sound subsystem. WASAPI connects to the DAC using its special driver, which take charge of things, not Windows. Again, the DAC-driver-port combination will be listed as a 'sound card', and you must properly configure it to work.

This is complicated because Windows permits 3rd party sound hw/sw to take control over its sound subsystem. An ASIO 'driver' can even take over Windows entire sound subsystem, bypassing everything, thus controlling everything.

If everything are configured properly and certain bitrates do not work, then 1) your S/PDIF sound card does not support it (not listed in 2) above), or listed but not checked, 2) you have sent the audio in an unsupported format, 3) your DAC does not support it from that input port, 4) wrong driver used.

[Grey Friar]

felix2,

Thank you for your prompt and very complete response to my inquiry. I went through your checklist and confirmed that all my settings are appropriate.  I also tried playing via Foobar 2000, with the WASAPI-Event Style plug-in, to make sure the problem was not unique to JRiver MC. Same result: 88.1 and 176.2 kHz files generated an error message; 192 kHz files looked to be playing bit-perfectly, but no sound.

My Intel DH67GD board specs SPDIF output capability of 32-192 kHz, as does the Realtek ALC892 chipset/driver...and everything works as intended through the Juli@ soundcard.  I'm still at a loss.

The motivation for this whole effort was to compare to the approach used by Baetis Audio in their highly-reviewed servers using "SPDIF done right."  I used an even lower leakage pulse transformer than they appear to be using to galvanically isolate the output from computer electrical noise.  I did, however, just notice in their literature that 176.2 kHz bit streams must be either up-sampled or down-sampled to play, so there must be some unique issue with 176.2 kHz.

[glynor]

I split this from Jim's Weird and Wonderful thread.  Not sure if it is already answered elsewhere.

EDIT: I found and merged in his other thread, which was buried over on the PC and Hardware board.

[6233638]

Are 88.2 kHz or 176.4 kHz rates supported by the device?
Check Windows' Sound Control Panel.
A surprising number of devices only support multiples of 48 kHz once you get above 44.1 kHz (and 44.1 is likely resampled to 48)