Seems that there is little attention to it, but it relates to the same issue I have raised on 24/10 in this thread.
Afterwards, submitting a few logs (w/o particularly raising the issue on the forum) and attempting to push an individual message to support on the forum I decided to examine it (I have 4 active Volumio devices and 3 DACs to test around) and as a Premium user I felt this is a nasty issue of losing the anticipated quality of the sound…
Issue:
a) irrespective of DSD settings (direct or DoP) and resampling (off or up to 768kHz target), USB output is always PCM limited to max 384kHz
b) this is observed on 3.* versions, when logged in as Superstar
c) no problem at the same setup used but logged out / operating as Basic user
d) no issues with 2.9* versions at Superstar or Basic
Hypothesis:
Based on my tests, there is a guess that the issue might be related to the implementation of the multi-room sync playback in Volumio 3.
For multi-room sync ALSA is deployed via conversion (creating loopback devices for PCM streams rather than HW) which cannot be disabled. And this might limit Premium users to lower quality than Basic users.
See tests & logs below to illustrate my idea.
Here are 2 test logs to illustrate it with the following setup
Setup: Raspberry Pi 4 8Gb + Topping D90SE DAC (ESS9038PRO) on USB (max native DSD512, PCM768). Only one device is active on the network (to avoid confusion with multi-room).
Fresh boot, all plugins disabled, output → USB, DSD direct, no mixer, no resampling. Live log enabled, then all setup reconfirmed and played test sequence.
10 test files in a sequence (PCM 44.1->88.2->176.4->352.8->44.1 MQA, then DSD64->128>256->512, them PCM 768)
First part of log - Superstar user / then logged out (Basic) for the second.
1) Volumio 3.159 test log:
http://logs.volumio.org/volumiobuster/650lpx5.html
Results confirm b+c issue (see above):
Anything = OK (i.e. DAC received on USB bitstream that matches the file correctly) for the Basic user (when not logged in).
For Superstar:
= OK: for PCM 44.1-352.8
= TO CONSIDER: 44.1 MQA played back at 44.1 and MQA was not available for the unfold (Volumio 2.917 did the same unfolding → 352.8)
= FAILED: DSD output always PCM (352.8k for DSD64, 284k for DSD128-256-512 and PCM768)
Note: when upsampling is enabled later, it always maxes out at 384kHz (irrespective of 768kHz target rate enabled)
2) Volumio 2.917 test log:
http://logs.volumio.org/volumio/AK775hy.html
Results confirm d (above)
= ALL TESTS OK (including MQA unfolded correctly for both Premium and logged-off/Basic users)
Few extra tests
The same results are achieved using other DAC - Topping E50 (ESS9068, USB max native DSD512, PCM768). Did not attach logs for these to keep it shorter.
Test of another Pi device (Pi 400 4Gb) - same results on both DACs.
Test of x86 setup - same results again…
When tested MoOde 7.60 (5.4.7 kernel based) on the same Pi 4 + Topping D90SE and E50 setup - discovered that:
- when multi-room is enabled, loopback device is created and the setup works at PCM up to 384kHz as a limit (and MoOde states it in in-app help)
- when multi-room is disabled, none of these limitations occur
CONCLUSIONS
- the synced multi-room implementation might be the issue
- as multi-room is available for Premium users only, they unwillingly fall victims to this implementation:
- Basic users do not get Manifest UI (which I really love) and multi-room, but they get audiophile sound
- Premium users get UI & multi-room but due to the latter, they do not get the option to enjoy the best sound
This is a shame from the perspective of Premium user’s perspective - likely a discerning and audiophile crowd…
3) a quick fix for this trade-off between quality vs features is an option to switch off multi-room is recommended to be made available for Premium users
As a Premium user, I would prefer Manifest UI + good sound over less frequently used synced multi-room. If I enable it, I would accept lower quality knowingly.
- In a long-term, obviously a proper fix would be appreciated anyway…
I hope this helps the developers to do the fantastic job they do for us - Volumio is great and I hope it will become even better.