In the last times I’ve been researching on how to improve the Sound Quality of Volumio, particularly with USB DACs, trying to squeeze the best out of the Raspberry PI and its USB BUS.
I’ve always been very skeptical when it came to Real-Time kernel usefulness for audio reproduction: my belief was that they were really useful when producing music, and their use in music playback did have little logic reason.
However, on the Raspberry PI, a RT kernel significantly mitigates the USB IRQ issues, and I must admit I’ve been pretty surprised by the sonic results of the tweaks I made.
I’ve also took the chance to add some USB Quirks to enable DSD Direct on a wider range of DACs. For some reasons that I don’t understand, currently enabling DSD direct requires the USB VID\PID of a particular DAC to be added to a list in the Kernel. I really hope in the future the Linux kernel will adopt a better and standardized way of recognizing such capability.
Also, I’ve implemented a patch to handle properly DSD silence, and avoid the nasty bumps when skipping, playing or stopping DSD in DSD Direct mode (it’s not included in 4.9, but it is in 4.10).
So I’m publishing this experimental release to know your feedback, and if you notice any improvement or degradation, compared to previous builds.
I’m trying the most empirical approach, but I am really keen to hear some subjective impressions from you guys.
Please note, this is an experimental release, and it will be excluded from normal update cycles, so if you would like to retain your settings and use future OTA updates, make sure you try this on a spare SD Card. Also make sure, that every time you select an audio device, restart your system for the optimizations to happen (this won’t be necessary in future builds).
Last, this is only compatible with Raspberry PI2 and 3.
You can download it here:
updates.volumio.org/pi/volumiort … pi.img.zip
Enjoy and let me know!