Regarding Android music player apps to run on the N6ii: Following the recent discussion about whether MQA is done properly on our DAP, I did a comprehensive study on what the various apps are doing to replay the various audio digitization (PCM, DSD) and encoding / file formats (FLAC, MQA). I used the Android Debug Bridge from my PC to the N6ii, and I looked at the AudioFlinger outputs (the last element in the Android audio stack before alsa which is the lowest one). I hope my way of diagnosing is good, and that my results are trustworthy.
In short, I could prove that three apps are doing everything they do correctly, i.e. in a bit-perfect way: Cayin, HiBy, and Neutron. UAPP does PCM alright, but it simply cannot do native DSD; I found it to always fall back to D2P, as confirmed then by the developer. I didn‘t check PowerAmp. I also looked at the original Qobuz and Tidal apps, both in streaming and offlining.
So, for me, Neutron has become the go-to app to replay audio stored locally on my N6ii and on devices on my home WiFi network. Fortunately, Neutron is also way more stable than UAPP when playing from my home WiFi. A matter of taste: The UI of Neutron is often seen as too complicated, but anybody who did master foobar2000 on Windows will master Neutron easily.
I found no issues with the original Tidal app, except for the discussions (cf. above, started by
@Taz777) on how MQA should be handled.
With the original Qobuz app, I stumbled over two serious issues, both of which I brought up to the Qobuz customer support. The current status of these inquiries is ”we have forwarded your issue to the developers, they will follow up on it“ - hmm, a well-known answer. Hope for the best... The two issues are:
(1) From AudioFlinger, I just see 16 bit resolution only, but never 24 bits. OMG! This holds for a whole lot of HiRes files, both in streaming and offlining. Of course, I made as sure as I can that my subscription and my app settings are good. I hope this matter will get resolved by Qobuz at some point in the near future!
(2) For offlining, Qobuz has opted to use a chunk file method (similar to YouTube): A track gets split into 2MB chunks, plus encryption. Since I offlined approx. 100 albums in various qualities from CD to all sorts of HiRes, I have 50,000 chunk files on my SD card (SanDisk ExtremePro 1 TB). Any action that makes the N6ii Android read in that storage space is an unbearable burden on the N6ii. First, I am used now to switching it on 1/2 hour before I want to listen to music (any music, not just Qobuz!), since the first read of that particular directory on the SD card takes that long. Second, the Qobuz App takes a certain time to gather an offlined album and track. Third, skipping forward or backward within a track and from track to track takes unpleasantly long, too.
So, to all of you out there: I can provide many more details on my investigation and results - just let me know, maybe via PM. And it would be great if someone could jump in, do the same or different diagnoses, and confirm or reject my findings. Some findings I mentioned are indeed VERY serious as far as I understand matters. Any feedback is highly welcome, in public or via PM.