On Thu, August 8, 2019 6:39 pm, crocket wrote: Often that is the case, but you would have to consult the documentation for your particular audio interface to verify. -- Chris Caudle

Would alsa_in be confused and spew pops and clicks if SPDIF out stops emitting clock signals in the absence of audio signals? On Fri, Aug 9, 2019 at 11:18 AM Chris Caudle <chris(a)chriscaudle.org> wrote:

If SPDIF Out stops emitting clock signals in the absence of audio signals, would alsa_out working on the headphone jack of the USB soundcard that gets its clock signals from SPDIF Out emit pops and clicks? Basically, the plan is 1. ALSA dmix(period size 512, periods 3) --> SPDIF Out of onboard soundcard(Realtek ALC887) --> SPDIF In of Creative Sound Blaster X-Fi HD USB --(alsa_in, period_size 512, periods 3)--> netjack1 ==(ethernet)==> ALSA jack backend --> Amplifier --> Speakers 2. netjack1 --(alsa_out, period_size 512, periods 3)--> headphones I have my own software for managing jack connections. A keyboard shortcut can switch clients between speakers and headphones. On Fri, Aug 9, 2019 at 11:18 AM Chris Caudle <chris(a)chriscaudle.org> wrote:

I'm trying to share speakers with my desktop computer and Raspberry Pi 3 B+. Both machines should be able to play audio simultaneously. --> is a connection that doesn't cross the boundary of a computer. ==> is a connection that occurs between two computers. Anything that doesn't cross ==> occurs on my desktop computer. Anything that happens after ==> occurs on Raspberry Pi 3 B+. netjack1 runs on my desktop computer. Ethernet cable is the only cable that connects two machines. 1. ALSA dmix --> SPDIF out of Realtek ALC887 onboard soundcard --> SPDIF In of X-Fi HD USB --(alsa_in or zita-a2j)--> netjack1 ==(ethernet cable)==> ALSA jack backend --> I2S Amplifier(HiFiBerry Amp2) --> Speakers 2. netjack1 --(alsa_out or zita-j2a)--> headphone jack of X-Fi HD USB on my desktop computer --> headphones netjack1 can route audio to either headphones or HiFiBerry Amp2. I can control routing via a keyboard shortcut. netjack1 can accept audio from alsa_in, zita-a2j, or just regular JACK clients like mpv. Here are questions. 1. If SPDIF out of Realtek ALC887 onboard soundcard stops emitting clock signals, would the following audio route cause pops and clicks in alsa_out or zita-j2a? mpv --> netjack1 --(alsa_out or zita-j2a)--> headhpone jack of X-Fi HD USB --> headphones I suspect that if SPDIF out doesn't emit clock signals and the clock source for X-Fi HD is SPDIF, alsa_out can misbehave. If SPDIF out may not emit clock signals in the absence of audio signals, everything should be routed via SPDIF out. 2. If SPDIF out stops emitting clock signals in the absence of audio signals and starts emitting them again in the presence of audio signals, can alsa_in or alsa_out be confused and inject pops and clicks into audio? On Fri, Aug 9, 2019 at 11:08 PM Chris Caudle <chris(a)chriscaudle.org> wrote:

* Does clock source matter if alsa_in resamples every audio sample to jack server's clock? Is it impossible to extract audio sample without knowing clock? * How can I have my computer automatically switch clock source between SPDIF and internal? Is there a clock source named "SPDIF or internal"? On Fri, Aug 9, 2019 at 7:21 AM Chris Caudle <chris(a)chriscaudle.org> wrote:

If I set the clock source of a USB soundcard to SPDIF, would the headphone jack of the USB soundcard conform to the SPDIF clock, too? Or, does the SPDIF clock source apply only to SPDIF In? On Fri, Aug 9, 2019 at 7:21 AM Chris Caudle <chris(a)chriscaudle.org> wrote:

I suspect SPDIF clock sour means that either SPDIF out or SPDIF in is not of high quality and you need better sound cards for both SPDIF out and SPDIF in. On Fri, Aug 9, 2019 at 9:18 AM <liebrecht(a)grossmann-venter.com> wrote:

On Thu, August 8, 2019 8:18 pm, crocket wrote: It is just because the window is not wide enough, it is the first part of "SPDIF clock source" but there is not enough room for the last two letters. -- Chris Caudle

On Thu, August 8, 2019 6:56 pm, crocket wrote: You would have to check the documentation for your particular interface, but in most cases yes, the digital to analog converter for the headphone jack would share a single clock domain with the rest of the audio interface. Typically and audio interface will have only one clock source active for the entire interface. That does not have to be the case, but in almost every instance that is what is most useful, so every interface I have seen works that way. -- Chris Caudle