How the JACK Sound Daemon is capable of running at 192kHz

Most of my Linux-computers have as their sound-server ““. But specifically on my laptop named ‘‘, I have set up the to be able to run as an alternative, yet not to be running by default. I have performed experiments on that laptop, to confirm that I can launch this sound-server, using a GUI named ‘‘, but have also had to make modifications to how this GUI executes commands from the user, so that its start-up pauses the , which has been able to resume successfully after I was done using . Without such a detail, the attempt should not be made.

One fact which I can see in , is that is capable of running at 192kHz, even though it has not interrogated any of the available devices, about their real capabilities are.

The reason this is possible is the fact that individual sound devices are just clients to that daemon, including any number of devices that act as sound-sources, rather than acting as sinks, i.e. that act as inputs rather than as one output.

I also own a USB-Sound-Device named the ‘‘, which is mainly intended for use in sound capture, but which also has outputs intended for monitoring purposes.

If I was to run at 192kHz, then one simple consequence of that would be, that zero actual sound-devices would remain compatible with it. As to how cleanly an attempt to connect to an incompatible device exits, giving error messages or crashes, I have not tested, because when I tested the , I took into account the real limit of that device at 96kHz.

Similarly, the runs with 32-bit linear precision by default. In this case, when we enable devices to act as clients, which are only capable of 24-bit sample-depth, which is common, the mismatch is safely ignored. already sees to it, that the last 8 bits of precision get ignored.

Now, I could be cautious and worry, that because of errors in the Linux drivers, those last 8 bits somehow get mapped to a control register as an error. But then the simple way to test for that, was simply to send some 32-bit sound through JACK, to this output device. What I found when testing this, is that the basic operation of the was not disturbed, even though my hearing was not good enough, to tell me when I had my Sennheisers on, whether in fact 24-bit precision was still working. I was mainly testing, that trying to send a 32-bit value, does not disrupt the actual operation.

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