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In Reply to: RE: An insolent provocation .... if a usb dac is very well design (and built) the pc quality should not matter posted by beppe61 on December 10, 2014 at 00:12:52
The effect of the PC depends on a lot of different factors. Using USB makes it more difficult to get computer independence. The best way I believe is to use network renderer. This way the data is packetized, the system is galvaically isolated and most important, the audio stack can be mostly avoided.
Follow Ups:
Or you could use a DAC that does that instead of that hypersensitive Empirical Audio crap.
Hi and thanks a lot for the kind reply
May i ask what is a " network renderer " ?
I do not have a clue ... but i am curious of course.
Thanks again.
Kind regards,
bg
It is an Ethernet interface rather than a USB interface. Takes packets off Ethernet and buffers them, reclocks them and reformats them. Then outputs on I2S, S/PDIF or AES/EBU. If you don't know what Ethernet is, it is the wired version of WiFi. Your router usually has several Ethernet connections.Can be an external device or designed into a DAC. It can be designed with many different embedded processors running various operating systems. It is not usually a general purpose computer.
Edits: 12/13/14
Hi thanks for the kind reply and sorry for the delay
Does this network renderer have to have an internal dac ?
because if it is a network streamer many of them rely on external dac, with usb input or spdif input.
So the interface issue is still present.
Can you give me some commercial examples ?
Thanks again.
Kind regards,
bg
This renderer evidently does not have an internal DAC. Another is the Rendu:
http://www.rendu.sonore.us/rendu.html
Hi and thanks for the suggestion but in this case we can have again the issue of the interface at the spdif out
A nice thing instead would be a renderer that connects via ethernet (or wireless) to a LAN but output directly an analog signal
That would avoid any interface issue ?
No usb and no spdif ... only analog outs
I wonder if renderers with analog outs exist
Thanks again.
Kind regards,
bg
Edits: 12/16/14
You are talking about a renderer interface on a DAC. Sure, they exist, but the DACs are usually sub-par. I believe the Sony streamer does this. Wireless can be added with an external device to a wired-Ethernet device.
Hi,
A "Network Render" is a custom build Computer aimed at playing audio (or Audio/Video) via network connections. A prime example is the Popcornhour range.
It is build from the same commodity hardware parts as general purpose computers and uses fundamentally the same kinds of designs and design techniques, but omits functions/memory/processing power not required for the audio or AV role and it may (or may not) provide improved circuitry for the audio or AV functions.
Operating systems are generally modified/optimised/stripped down general purpose OS (Linux and Windows embedded are most often found).
In many cases the commodity type network renders are less expensive than general purpose computers purchased new at full retail (though more than you pay for a "leftover laptop" which is free).
Some are marketed squarely at the high end audio market and command large premiums. The degree of customisation for these devices ranges from fully custom build designs to generic PC or phone/tablet hardware bodged into fancy boxes with expensive looking front-plates.
Ciao T
At 20 bits, you are on the verge of dynamic range covering fly-farts-at-20-feet to untolerable pain. Really, what more could we need?
Hi and thanks a lot for the kind explanation
A very interesting approach indeed
But also very difficult and for expert like the choice of the OS
I read that Linux, for instance, runs also with low resources
Does this maybe mean that is more "effective" of the others ?
Does this make it a better OS ?
I am thinking to try Ubuntu but i am quite scared
I would only need a good SW to play media files then
Then i have also to check if my pc is compatible
For instance the NUC has no official drivers for Ubuntu
Is Ubuntu a better OS than win 7 64 bit ? i am not able to slim win 7 down so i am referring to the recommended installation of the OS
Thanks again.
Kind regards,
bg
Edits: 12/12/14
We can have conversations with all new, different, and undefined terms, so no one knows what we're talking about.Our Squeezebox touchs are "network rendering, streamers, music servers, mini computers"
Or we can call them NRSMSMCs for those wishing to proceed further down the path of obfuscation and pedantry.
NETWORK RENDERING traditionally is VIDEO. Typically, it means to "fill in" or "render in" skins over 3 dimensional vertices, (covering them). Rendering these complicated 3D wire frames would often take many hours and A network rendering program would utilize the processing power of many individual PCs, and servers, in a network to "cover" these wire frames.
Likely, in this case, - he probably means something like the Aries, SoTM, Bryston, Sim Audio Mind, - etc.
Cheers,
"Asylums with doors open wide,
Where people had paid to see inside,
For entertainment they watch his body twist
Behind his eyes he says, 'I still exist.'"
Edits: 12/11/14
The term Network Renderer was chosen by the committee that developed the DLNA standard.
.
"Asylums with doors open wide,
Where people had paid to see inside,
For entertainment they watch his body twist
Behind his eyes he says, 'I still exist.'"
Hi and thanks and sorry for the belated reply
Now i have understood and i have to say that if keeping things simpler is better these network streamers makes a strong sense.
The average guy has audio, video and internet on the same pc.
I am convinced now that internet must be absolutely avoided
Video maybe can live together with audio
Audio only would be the best
So for audio streaming only the HW can be quite reduced
Personally i am following a lot the Android streamers
The OS is very fashionable and there are many update
My next idea would be to try an Android media streamer with a usb dac
Or viceversa if only i could find a usb dac with Android drivers ...
Thanks again.
Kind regards,
bg
Consumers tweaking computers and becoming their own "designer" or "manufacturer" is a recipe for disaster.
When we push toward superior playback with our computers that are not designed for high end audio playback, (indeed designed to be the antithesis of great playback), we are on a fools errand.
In no world is a Mytek DAC EVER going to be as good as anything that says Meitner on it at 10 times the price. The elements that go into building a great DAC have stayed the same since 2000.
This is also the case with transports. No computer can ever be made into a SOTA transport.
Most people here are not interested in SOTA, and that's fine. But traditionally, SOTA tech & ideas "trickle" down to the rest of the high-end and even lower. The examples of this, are almost too numerous to mention.
I contend that before one wastes time trying to violate a computer, that one does some basic Squeezebox optimization, or picks up a Sim Audio Mind, and does some comparisons.
"Asylums with doors open wide,
Where people had paid to see inside,
For entertainment they watch his body twist
Behind his eyes he says, 'I still exist.'"
I believe there are different protocols involved. The bits sent over the Ethernet are not the same. Protocols designed for use over a local area network on dedicated links can be considerably simpler and more efficient than those that must run over arbitrary networks including the Internet. This impacts the processing that is located close to the DAC and hence, potentially the sound. Unfortunately, in both cases, as with USB, there is still a lot of processing, something that requires a considerable amount of computing power and the likely noise.
Most product terminology is created for marketing purposes. A classic example is "Direct Stream Digital" which is nothing but 2822.4/1 PCM rather than 44.1/16 PCM. Of course when one looks at the format this way one immediately sees DSD has high sampling rate (good) and DSD has low bit depth (bad) and hence one expects there to be tradeoffs, as in fact there are. This is all about creating market niches, publicity and in some cases cults.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Tony, you claim Ethernet require a considerable amount of computing power and processing. Really now?
A network player, streamer, whatever you want to call it, the size of a pack of cards will have absolutely no trouble streaming a 24/192 WAV, FLAC, or AIFF file. None. That is because it is designed to do nothing else.
I think we continue to chase phantom problems in computer audio.
You have to look at peak processing, not average processing. If you transfer the samples one at a time to the DAC then it processes them one at a time. The processing cycles at the sample rate. If you transfer samples a buffer at a time, then the processing takes place each time a buffer arrives. This results in a busy period followed by an idle period at the buffer rate. Given typical packet sizes the cycle time will be in the middle of the audio range, e.g. 1 kHz for USB. The numbers will be similar for Ethernet. Noise associated with this processing may be audible. This is similar to the situation that many people have observed in computer audio where reducing the buffer size improves the sound quality up to the point where buffer overruns start happening and audible glitches appear.
These are real problems. There is a lot of debate about why these effects happen and what the best (or most economical) way of dealing with them might be. However, careful listeners all notice that bits are not bits, or at least usually do not appear to be such. There is spirited debate as to what to do about it. Of course there are people who deny this can happen, but you will find them on other forums.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
I understand what you are saying.
However, explain what kind of noise can affect playback when the computer/NAS never directly interface, and only communicate via a router, and 30 feet of shielded CAT7 cable
Noise can be coupled at least three ways, through the air with cables acting as antennas, through the power wiring and through the signal cabling. You can test (and rule out or rule in) the first two possibilities by running the computer after the streamer has been disconnected from the network. (You may have to fake it out so that it thinks it's still playing, details would depend on system and network.) Shielding on the Ethernet cables will definitely help but there are various ways their effectiveness can be reduced.
Getting to the third possibility, different software in the computer or various hardware related noise will affect the speed at which the computer operates and hence the timing of packets sent through the router. If this timing is different then the router will forward packets to the streamer with different timing. The streamer gets a huge pulse of work each time a packet arrives and the required processing will create noise. If the streamer isn't isolated from the DAC then this noise will affect the audio. This is a good theory, and according to John Swensen, a theory that he has proven to apply in practice.
What this amounts to is that the streamer has a computer inside it and that computer has the opportunity to pollute the audio output of the DAC. I can't think of any way to avoid this possibility other than to isolate the DAC from the streamer. The fundamental problem is that computer components that are designed as digital circuitry are in close proximity with sensitive analog components such as the DACs master clock, converter power supply, DAC chip, IV converter and output buffer.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Thorsten's iFI iUSB creates isolation between computer/streamer and DAC.
What you will hear isn't the computer noise, just the packet processing noise. The timing of packet arrivals will depend on what goes on in the computer. Hence the timing of the packet processing noise depends on the computer. John Swensen has posted about observing this effect. Note: if you change the timing of the noise then the effect on the music will change, hence the listener may perceive differences. To hear consistent sound one will either have to reduce the noise to insignificant levels or time the noise so that it is consistently correlated with the music, or alternatively reduce the quality of the playback by various means such as adding much louder masking noise. This might hide any source differences, but this would not amount to a good outcome.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Yep, John Swenson has called this packet noise (maybe packet jitter?) & it is really the result of the receiver chips self generated noise when packets arrive & processing of these packets occurs. The concept being that this burst of processing causes a current draw on the PS which can effectively result in noise on the PS/ground plane & this noise effecting other parts of the system that are also using this PDN (power Distribution Network).One way of addressing this is to read the whole audio file into local RAM at the DAC & closing down the connection before processing of the audio file from RAM by the DAC chip.
Another way would be to attempt to kill any possible PDN noise when processing this bursty data
Or a final way, might be to ensure the packet bursts do not have a frequency that effects the audio band directly?
Edit: I see my points were already made - sorry for the noise :)
There may be another issue - the signal integrity of the waveform that represents the digital bits? Could a worse SI waveform result in a different sound to a good SI waveform because of similar processing issues in the receiving chip?My thinking is that DACs connected to computers are effected by a mix of 3 possible issues:
- noise conducted via the wire connection (usually common mode)
- bursty packet self-generated noise
- signal integrity self-generated noise
Edits: 12/12/14 12/12/14 12/12/14 12/12/14
These are TCP/IP connections with the typical, (physical, transport, internet, data-link, & application layers). When rendering 3D video object vertices, - it's all TCP/IP.With digital music playback transports, - it also uses TCP/IP to either grab the file and load it into memory, - or play it, (stream), it from the box.
These are not marketing terms: they are old computer terms to describe the packet transport performed by the TCP/IP protocol: correct?
The terms created to describe the events are not of a concern, it's a question of how we define things, so that we all understand what we're talking about. The term "DSD" no matter who created it, is fine until the point where it gets confused with other terms, or it's used erroneously. If we start with DSD discs, SACDs, it was clear that DSD was something entirely different than redbook, (also not the most creative term).
The point of my post was that we should come to some sort of consensus about some of these definitions, or we're going to be spitting into the wind in two different languages, blathering lunacy.
The OP asked what was meant by "Network Renderer" we still don't know.
"Asylums with doors open wide,
Where people had paid to see inside,
For entertainment they watch his body twist
Behind his eyes he says, 'I still exist.'"
Edits: 12/11/14
I may be mistaken, but I don't believe that the new standards for studio audio use TCP. Audio is transferred in hard real-time with absolutely minimal buffering as would be required for sound on sound studio use. (I haven't studied the protocols as the standards are beyhind a paywall.)
One thing is pretty clear, and that is that the Squeezebox protocol is source independent. Once you buffer ahead sufficiently, you can pull the plug and power down the source, playing out of memory on the Squeezebox. At this point there will be little scope for the source to affect the sound quality. (Or maybe not, but if you go there then it is only a small step to worrying about the Ethernet cable at the HDtracks sever to the HDtracks router. Personally, I worry more about the record label shysters marshaling the files that get uploaded to the server.)
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
the same applies to all the streamers I have in my systems. I can shut down my server software and my computer with my library attached and I can get sometimes two more songs to play.
Yes, isolation of source and DAC. You are starting to get it.
Best way to isolate the source and the "DAC" is to stream the entire playlist at gigabit speeds to the "DAC", power down the source and the network connection and listen to the music out of memory in the "DAC". This was done a decade ago for CDs with the "Memory Player".
This won't work for some applications, such as streaming from the Internet or studio processes such as sound on sound or editing, but this will eliminate the "source" from the equation. If you are impatient then you had best not do any DSP in the computer or if you do so you had best have a very fast multi-core processor, or you can do your preprocessing off-line and store the results on disk if you have stock in Seagate, Western Digital or Hitachi.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
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