spartan1969

Thank you. After cleaning my qobuz cache the problem seemed to be less pronounced; and after my last qobuz and system update, it is playing like the other streaming services. But this has already happened in the past and then, for some reason, the problem reappears. It might be related to qobuz cache messing up with clocking somehow. I'm using a 2017 iPad with camera adapter.

android x ios I also wonder if people here have had the chance to compare using android and ios. I suppose it would be a though thing to compare given the potential deep differences btw the tablets being compared too. It would be interesting to have some feedback on this matter anyway.

I don't know how and doubt there's a way to check bit depth integrity while playing a file through Qobuz. Whatever is going on, it might or might not affect bit integrity. It might be an issue with clocking as I said. I don't know. With other players like Amazon music or Apple, if the same happens, it is on a far more subtle level. If you're using an iphone and just listening through headphones, I believe there's no way you'll tell the difference. The issue becomes clear on a state-of-the art purist system. We were able to compare ipad/qobuz (optimized ipad, of course) with computers and dedicated streamers costing sometimes tens of thousands of dollars. Our conclusion was that it makes no sense to go other way. The real difference one can have, supposing the streamer used is sending the data bit perfect, is on the conversion from the usb signal to spdif and the connection to the dac. But that's a different subject. The only issue we're having is the one described above. Unfortunately, the other streaming options suck as interface and in other ways compared to qobus. Tdal with its disgusting MQA is not an option. Apple and Amazon have other issues, not to mention being what those companies are... Bear in mind that we have not tested all ipad models, perhaps with the new versions the issue disappears.

Sound quality issue with iOS We have been using qobuz in our studio for years as our main streaming service. We have done many demos with it and realized that if properly configured, for instance with a dedicated ipad, wifi off and other obvious sonic precautions, it can sound as a reference source, virtually matching other more "sophisticated" dedicated file players. Recently we have noticed a problem with qobuz that we simply do not have with other streaming softwares such as apple music, amazon or tidal. We are talking about the mobile version for iOS, which is what we use here. We have tested several ipads of different years and the problem really seems to be with qobuz. If we start the ipad, open qobuz and play a file (44.1K), it sounds perfect. If we replay the same song, it’s still fine. But the moment we chose another song from another album (44.1K), SQ drops with high frequency distortion being introduced. The distortion sounds like something on the clocking level. The average ear would probably not notice the change, but for our standards, it is enough to spoil the party… You can do some testing by playing first, immediately after startup, a very familiar file for 20 secs and repeating that file a couple of times. Then put on mute and play different files from different albums for a couple of seconds each, stopping and restarting them, etc. All files MUST have the same resolution, so all 44.1k. Then unmute and play the first file again for 20 seconds. You should be able to hear what I’m referring to. Again, it might be subtle, but it’s enough to downgrade the SQ to “lower quality” sound. We use different USB to spdif converters, such as the m2tech hiface 2. We have noticed this issue in the past when switching between hires and standard resolution files, which definitely changes the sound for worse and completely compromises SQ for us. So whenever we change the resolution we restart the ipad for optimal sound. Recently, as mentioned, I have compared qobuz to other softwares specifically on this issue and to our surprise only qobuz has the “glitch”. When it comes to changing the resolution though, none of the apps seems to keep the original SQ present at startup. It’s very odd that this sort of problem is present in services that are sold based on their superior sound quality. I wonder if anybody here has an explanation.

have you compared regular sdcard with micro sdcard for best sound? Some of these cards are much faster than others too. I wonder if it would pay off buying hte fastest. The only experiment I've tried with these was with a portable player and to my surprise a 32Gb card sounded better than larger cards of the same type (brand, series, etc).

I think I see it. The dX-USB HD is a sort of M2Tech hiface EVO, right?

Sorry for the confusion about the PSU. But no, I don't use the uptone supplies. What is the dX-USB HD then? I thought that what you meant by usb card... So you use three of those clocks in total (one in each unit). Can you actually fit them inside the original chassis? And do you power each clock with the same supply you use for the corresponding unit? As for windows sounding better, I never questioned that. I'm not particularly attached to the mini or to anything for that matter. Indeed, then why not just go with a PC (perhaps a 12v fanless PC) instead of the macmini? I'm sure booting from an sdcard on a PC would not be a problem.

Romaz, Thank you for the thorough reply. For the way you are involved with this project you are extremely generous with sharing your ideas and with your time! As for what you say above (quotes), couldn't we boot the Macmini with windows using the SATA SD card or SLC adapters you mentioned? I believe that was your assumption in your earlier post, no? Or your friends at Apple told you already it's a no go? What you say about the high frequency noise with SSD PCIE resonates with my recent experience testing an euphony SSD drive (a linux dedicated system pre-installed in an ssd drive) with my macmini. Similar things from your comparison with windows+ao X macmini+sdcard: slightly better definition, transparency, overall presentation, but polluted highs... Couldn't this be related to the SATA port instead of the SSD drive itself? I suppose SSD drives could be even worse than SSD PCIE (which I never tried) in terms of noise. At any rate, I'll try to test that linux system from an SD card. The question is if it will work. *** Allow me an aside: The thing about the macmini that people generally forget is how great it is IF it is used without any other electrical connection to it: no monitor, keyboard, mouse, no external HD or SSD, no ethernet (especially not from modem... horrible compromise!), and... yes, no USB, but just a very good optical cable (I know one that for under $200 beats by far every expensive USB cable I have tried so far). And no wifi or cel phones in the room, of course. Let's hold for a second the boring stuff about spdif's resolution limitation, DSD, etc. That's not my point. My point is that THAT source (with all the optimizations we have been describing here) can be really hard to beat in terms of musical satisfaction. Yes, of course things can always be improved, but this setup will put you on an extremely comfortable seat. We forget sometimes (and this is often true for every aspect of audio reproduction) that we can leave that seat with a big smile on our faces to an endless rollercoaster journey that is all but comfortable. Any way, my point is that one should start from here (at least if the Macmini is the core) as a sound reference and always come back to this basic setup for comparison. Also, let us not forget, in my case, certainly – and, I believe, 95% of people – that the vast majority of the music we listen is in standard resolution(s). So my reasoning is very simple: the SQ we have with THAT stuff should be our priority and thus our standard. For what would be the point of seriously worrying about DSD (or to any format that promises you the sound of angels without really telling you how to get there) if one has to sacrifice, even just a little bit of that standard (not to mention of his sanity)? I hope the aside was clear and that I’m not misinterpreted… *** Can you clarify the following points?: For all your tests, is the router connected to the computer or do you break that ethernet connection (using it ONLY when needed, namely with streaming services like tidal and other internet stuff)? Still not quite clear (sorry...) which ext. clock(s) do you use (model) and how many? Is it just the one you had installed in the switch? By "UBS Card" you mean the SOtM unit? Can you repeat which model? And why would it be really a gain after the sms200? I thought the latter had already an optimized USB "card". One last thing. I'm curious to know what makes you think the PSU I use has a lower impedance than yours... I know the Hynes regulators very well.

oh, thanks for the help... but did you read my first post?

You must mean without having the router as the hub, right? The router is still connected somewhere I presume... I believe that's what I have here: two computers connected through ethernet. But one of them connects to the router (otherwise, how do you have streaming service?), the other is the end computer with the sdcard. In any case, I was not asking about the term "direct connection", but the rest of the quote : "For those of us who apply proper care and attention to our upstream components, we are rewarded for our efforts and for those of us who don't, there are sonic penalties. "

Thanks. Can you just explain what you mean by "direct connection"? Maybe I'm missing the terms here...

Hi Romaz, Can you please explain what precisely do you mean by the passage in quotes here? More specifically to file storage, what is giving you the best results now. The SATA adaptor to SDcards you mentioned is interesting. Did you suggest that SD cards are a better solution for storage (in terms of SQ) than the alternatives? That has been my suspicion too. If so, is there a way, or adaptor, you have tried, that allows us to use extra SD cards (other than, of course, the SD card used for the system) for storage? I'm too having a very fine SQ with the MacMini booted from SDcard with El Capitain. Moreover, I'm using a mac-to-mac connection as suggested by Superdad a few years ago. Also, my macmini is already on the best PS I can think of and I'm using Roon. All those "extra things" you're using (microrendu, sms200, clocks, switch, USBoptimizer, and respective supplies) can become very expensive and a small nightmare in terms of space, cables, etc. Pardon me if I hesitate a bit... but it's a potential mess, as you'll probably agree. I have read this entire thread and one would be silly not to believe your findings, as they are very well explained and documented. But if you compare the macmini-sdcard system (the one I'm using) with that same system plus all the extras in question (apparently what you are using), do you think now it really pays off? In other words, unplug all those "extra" supplies from the wall (remove all the "extras" from the room if possible) and play the mini for a while. Now connect all the extras and listen. What happens? I'm asking this apparently redundant question because a few post ahead you said you have returned to the sdcard with elcapitain with great relief. And sometimes we travel great lengths looking for improvement to realize much later that what we had before was better. Was that (at least partially) the case? By the way, what OS system are you planning to use in your future server (nice project!) Thanks, Spartan

What CD player or transport you have in mind, my friend?... Please let me know what are you comparing, even if in retrospect, to what.