I am running two Cubox-i4 units in my house, both using Volumio 1.5 and kernel 3.14.14.
One talks USB to a Schiit Bifrost Uber and the results are great (wonderful sound, no dropouts, nothing to complain about).
One talks USB to an AudioQuest Dragonfly (1.0) and the results are almost but not quite great. What is the problem?
On 44.1/16 music there appears occasional loud crackly static sounds, much like a noisy LP record.
This problem does not occur on 96/24 or 88/24 music.
I can make the problem less frequent by tweaking the buffer (10% seems to work better than 20%) and also by messing with the kernel parameters (ACX seems to work the best). But it doesn’t go away completely.
I also see a number of the following types of messages in dmesg:
[64299.012555] 2:1:1: cannot get freq at ep 0x1
and very occasionally
[63318.381614] cannot submit urb 0, error -27: internal error
[ 255.251316] usb 2-1: USB disconnect, device number 2
I see on this list that many people have had problems with the AQ DragonFly (on Raspberries as well as Cuboxen). I also see other mentions of similar error messages and these often seem to be tied up with sound degradation.
Finally, there is a long thread over on launchpad that seems to indicate the problem came along in kernel 3.8 or so and may have gone away in 3.18 or so.
So, enough about me! Do any of you have any suggestions? Is there a newer kernel for the Cubox I can try that works with Volumio? Has anyone here fixed the problem in some other way?
Thanks in advance!