I tried playing CD and mp3 via HDMI in. The 10s mute is now down to about 0.5 s I'd say. Much better but not perfect. Still misses the beginning of some songs. I also encountered the "stutter" (as dsperber described it "Ta-Ta") after skipping etc. when the stream starts again.
Then I tried SPDIF (optical) and there it seems you don't have that problem. Just 0.5 s mute time and "soft" un-mute, as you expect!
So I recommend for 2ch PCM sources use SPDIF!
Had my own chance to reproduce your CD/SPDIF results today. I agree with your observation on the "stutter" (as you call it, which is definitely more accurate and professional sounding than my "ta-ta" which was the first thing that came to mind when I wanted to verbalize it). Definitely isn't there using PCM via optical input, whereas it is there with PCM via HDMI input. So I agree that for now, using optical input for CD audio seems the best choice and we'll have to live with the 0.5s mute time until Smyth eliminates the use of the decoder on PCM input.
So this was also my first opportunity to use an A16 input (optical) other than HDMI. And it also was yet another opportunity for me to interact with the level of user-friendliness (or not so much) currently built into the user interface. Others may feel this to be relatively unimportant on any to-do list when contrasted with true important promised functionality (e.g. DTS decoding) that is currently still not available. But my own feeling is that user interface is experienced 100% of every time you use the device, no matter what you're doing. And so any inconvenience which you run into EVERY TIME YOU WANT TO DO ANYTHING is really quite important.
Specifically, with regard to today's playing around with CD via optical vs. CD via HDMI, it is once again obvious that not having a power-on default VOLUME is a nuisance. At power-on I happened to be sitting on my preset 01 (5.1) which is perfectly usable for 2-channel CD audio, so that's where I was working. But my volume was still up around 79 from yesterday's usage. CD audio is much hotter than ordinary movies and HDTV, and reasonable listening volume for me needs to be around 63. So obviously I had to down-the-volume right away.
I also had set the INPUT for preset 01 to optical. That required going BACK to main menu, navigating down from the preset/UserA line to the INPUT line, and then sequentially ADJ + from HDMI2 up to coaxial (which I discovered is the very last input available). With headphones on while doing the ADJ + on INPUT, I noticed noise/pop when passing through the rest of the inputs, none of which had any input cable connected. I think it might have been the USB input which produced the "pop". Anyway, it took real time to complete all the finger-presses needed to finally get to optical input, and only then could I get back to preset 01 using PA.
And of course, when I wanted to repeat the testing again for HDMI I had to repeat the complete sequence of lots of finger-presses, but this time reversing the input with ADJ - multiple times to come down from coaxial to HDMI2. Once again, passing through USB produced the pop noise in my headphones.
And naturally, when I really want to watch HDTV tonight using that same 5.1 preset 01, I'm going to have to up-the-volume back to 79, because 62 is too low.
So, what would have been very convenient would have been to be able to set up two specially purposed for 2-channel PCM CD audio presets for A/B comparison. I shouldn't be playing around with my preset 01 which I should reserve for 5.1 HDTV, coming from HDMI1 and with default power-on volume of 79. One new special preset for CD audio testing would have HDMI2 as input, the other would have optical as input. Both would have say 62 as the power-on initial default volume.
Also, I would then want the ability to do an "instant random/direct selection" of either preset ideally through one or two two keys. Obviously it is of maximum convenience to the user when doing A/B comparisons to have fixed preset-selecting buttons on the remote like P1-P4 with the A8. Given that there are no hard-wired preset-selecting buttons on the A16 remote what might we come up with instead? I now propose one more A16 modification to add to the wish list of changes and improvements.
==> I PROPOSE THAT WHEN NOT IN "TEST" MODE (speaker solo with sound loop) THAT THE NUMERIC KEYPAD AREA REVERTS FROM SPEAKER-SOLO FUNCTIONALITY TO DIRECT PRESET-SELECTION PURPOSE.
It seems a real waste to permanently allocate the 12 numeric keypad buttons at the bottom of the remote to the truly relatively rarely used purpose of soloing Atmos speakers. The 11 engraved speaker-solo buttons in the top part of the remote are probably the most commonly used speaker-solo buttons because they apply to 5.1/7.1 sound systems. And the 12 numeric keypad buttons can be brought back into use as speaker-solo buttons when the TEST button is pressed. Until TEST is pressed again to get out of speaker solo mode and back to normal mode, the numeric keypad can be the assignable speaker-solo buttons as they are today.
But when operating in normal mode (i.e. WHEN NOT IN TEST), and really as soon as the PA/PB buttons are pressed, the 12 keys of the numeric keypad instead BECOME THE DIRECT-SELECTION buttons for presets. In other words they are now P1-P12 for the A16. (don't have an answer yet for presets P13-P16, but I'll leave that as of really really minor concern to me). This does lose today's capability to do "live solo" of speakers, using actual live source sound on that channel (as opposed to the music loop from TEST). But I'm very willing to give up that really really rarely needed "demo" use of Atmos speaker soloing (for speakers not in the 7.1 plane) to instead have direct preset keys P1-P12.
PROBLEM SOLVED!!! Our remote now has preset-selecting keys P1-P12!!! The 12-key numeric keypad area will be re-purposed primarily for direct preset selection, unless in TEST mode when it will revert to today's speaker-solo function.
And, if each preset can also have its own NVRAM power-on default value for both VOLUME and INPUT, well now we're really making progress. Zero need to push keys zillions of times to navigate sequentially using BACK, arrow up/down, ADJ +/-, because direct selection isn't possible for the very primary one or two variables central to what we're really A/B comparing. All we have to do is properly set up one or two (or more) presets to reflect not only VOLUME and INPUT but also the assorted significant variables we're probably really wanting to compare (including the true main ones, like PRIR, HPEQ, etc.) and then we can do an INSTANT ONE-CLICK A/B COMPARE by simply pressing the numeric keys.
I suspect there will still be a several second delay when switching presets (as there is today, to populate all the variables needed to present the speaker map display) so it won't really be an "instant" A/B comparison. But it will at least be a single-click A/B comparison. WHAT A RELIEF!!
Sure would have simplified my testing today with optical vs. HDMI input for CD audio.