to Steve:
Why do you advise against *lossless* formats like FLAC/ALAC?
They are, after all, lossless, and after reconstruction are identical to RAW. And, I have compared and heard absolutely no difference. I admit i have not compared many times or particularly carefully since (danger will robinson!) i knew what the result would be :-)
No, on low powered computers or slow disks i could see it causing more power noise or even jitter/errors, but that would show up.
On re-reading your post i wonder if there is a subtlety in it, you actually say "avoid ripping to ALAC or compressed file using itunes". Is itunes somehow the problem(how?) or ALAC, which, after all, is lossless (mostly DPCM)?? TIA
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You have the basics above. I’ll just add a few comments.
First, think about the tasks - you need something to catalog and let you browse and select a file to play. Someone mentioned ROON, and i think that happens to be the pick of the streamer litter. Next, you need to get it to the room your stereo(s) is (are) in. This is any old ethernet network - not Wifi preferably (although it may work). Next you need to terminate the ethernet, convert it to either USB or SPDIF and provide that to your DAC which may be in a receiver or may be stand-alone. There are bunches of these, one by ALLO based on Raspberry Pi is excellent for the money.
Note that the digital signal DOES impact sound a lot, for good reasons, mostly 1) jitter and 2) noise, which causes 1) (jitter). Its HUGELY important. I was shocked.
Consider both what you need to get ot to play today, but also what you want for the future. I want a single server with a great interface for all my music, radio, streaming subscriptions etc. This will be ROON on a dedicated server (NUC/ROCK/custom linear supply). AS long as i can make that electrically and mechanically quiet i do plan to have that as part of my main system and drive my DAC via USB directly (well, galvanically isolated, but that’s about the noise bit).
Commercial streamers like SONOS and Bluesound simply combine some of these functions in the head-end and others int he remotes. SONOS, by the way, sounds awful in the context of true high-end. I was also shocked when i first heard that in a very good system. Switching ti CD was a relief.
I need to look up audioengr’s roll-you-r-own components to see what its about. I don’t think i’d give up ROON though.
G
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Picking up on the last response about streamers - read my post again. **something** needs to present you a UI, identify the files locally or on a network, and send it to the appropriate digital interface, somewhere on the other end will eb the DAC (depending on the interface).
The streamer may reside on the NAS in some cases. IMO, not a great idea. It can reside on the networked device. or it can be a stand-alone box like a ROOM server or BlueSound streamer. But it must be somewhere. A "head end" streamer has the advantage of using many source file locations and feeding many end points.
G
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Just to answer a few questions not addressed to me :-)
-- Why have the server in another room? I think to reduce physical noise (fans, etc.). I probably will just put it in a closet in the room. I'll also make a quiet server based on NUC, Roon ROCK, etc.
-- Why is Ethernet superior to USB? answer: both are asynchronous and therefore should be the same. But USB needs to be galvanically isolated to prevent noise propagation. Also, see above, network allows you to remote the whole thing and eliminate physical/mechanical noise
Otherwise there is no difference. Either vs SPDIF is a big difference however, since SPDIF is synchronous and depends on the source clock, which you cant control.
G
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"But, honestly, I just want to listen to music that sounds great and is easily located and selected."
:-) Don't we all. Let us know when you find it.
Ok, seriously, its not that easy, but yes BlueSound is supposedly pretty good. But you still either need to co-locate it with your DAC, or you need to get something to terminate the network in another room and feed either USB or SPDIF to your DAC, and therein lies more complexity if you want good sound. Its mostly about digital noise on the line and jitter.
G
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Audioengr wrote:"Most of what makes digital sound good has to with low jitter, and I mean
really, really low jitter, a few picoseconds. It's ALL ABOUT JITTER,
period."
I never say never or always, but i pretty much agree here. If you think about reproduction, each sample requries two points, plus smoothing/filtering. We have spent 35 years focusing on ONE point, voltage (bit depth) and pretty much ignored the other (timing). Over ten years ago i added a PLL (or two) to my cheap-o transport ( A CD player) and made a large leap forward.
Remember that jitter has many fathers too - noise, threshold detection, blah, blah, blah. I know nothing about Steve's stuff, but it certainly seems to have the right design objectives in mind. I have also had very good results with a relatively cheap Schiit EITR (USB - SPDIF).
G
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to oldschool1948
Steve has more bench experience with these so I wont even comment on his figures or claims. But I’ll provide a couple of data points that are useful to anyone trying to digest why jitter is worse in A than B.
First, SPDIF and its variants (including AES/EBU and toslink, which are merely physical layer manifestations) have the DAC as the SLAVE to the MASTER clock in the sending device (transport, CD player, adapter, streamer, whatever).
USB and Ethernet are asynchronous. the sender sends bits to a buffer until told to hold on... and the DAC clocks things out on its own, using whatever clock circuitry it has.
Beyond clock specs, we have to deal with detection of that clock, which might be on the lead (cab;e) on the internal bus, whatever. Lead lengths may vary, thresholds for detecting a clock pulse may vary, noise may interfere -- many functions can interfere with timing by small (to us) but large (to the music) amounts. Remember that the entire sample time slot for a 44k signal is 20 mSec (1/44000 sec) - yea simplified for illustration.
I suspect noise is a significant contributor since linear power supplies seem to improve sources in subjective testing and we KNOW (due to error correction) when there are errors and that the base clock was the same. I conclude that this ids also why the same signal over AES is reported to sound better than over Coax. We KNOW that optical toslink has a big jitter component, but the advantage of ground isolation (due to, well, no ground)
G
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Oh, a second answer - to your very last question: "how can you tell".
Well, given "one equation (or test) to one unknown" - you need to compare lower to higher jitter. Otherwise, you are hearing a system. Experience and training may tell you that sound X is related to cause Y, but that's tenuous.
Jitter is often blamed for the digital sound - the hard to define harsh un-naturalness that we've all heard. I will say that I have been able to compare a CD on a modest transport to the same CD, ripped ALAC, and played back through a MacBook Pro, bitperfect, and a well-thought-of but modestly priced USB--> SPDIF converter. All this thing can do (good anyway) is reduce jitter. The sound was less digital (ok, whatever that means) and more transparent. While levels were identical (duh) it sounded more dynamic, and more effortlessly so. There was more space between sounds. But it was very clear to all who heard it. It was also very clear when i got a bad feed into it switching back and forth, so that was a bit of a sanity test (sounded like crap, some USB weirdness).
Now this was not a super high end solution either, so there's more to be had. DAC was my "once upon a time it was a MSB Gold Full Nelson" Frankenstein test bed. Also the trusty old Theta that I've had for two decades.
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