[obobskivich]

I wouldn't worry so much about that kind of accuracy in the images BradJudy, mostly because its "over accurate" (you'd have to make a unique pic for every possible solution for it to be proper, essentially)

but <3 the effort you've put into these pics

and LOL @ the error "not a mechanical connection", thats pretty good when the only errors you can find are syntax, not content, again top notch FA

 

[BradJudy]

Thanks for the compliment, I think visual aids and consistent color coding help to reinforce the concept behind this thread. I'm now thinking that keeping the digital receiver as a separate item is pointless in the visuals (as per my note below).

I'm not sure if syntax items are the only things left to be discussed. For example, I'm not entirely sure that this statement is accurate:

"Source/Transport : USB Host Controller on computer motherboard
-> USB Audio 1.1 Stream over USB cable
Digital Receiver : PCM2704 USB receiver inside Stello DA100"

Is a PCM270x really a digital receiver or is it the source? The definition of source used here is the reading of the content and outputting of a digital stream. This is vague enough that it's hard to define the boundary of the system for computers (since it's all digital internally). I would argue that if an internal soundcard with a digital output is considered a "source" then a PCM270x should be considered a source. I think the boundary for a computer source should be where devices are no longer under the control/management of the computer (hence why I diagrammed it that way).

If my argument is valid, then it makes sense to fold the digital receiver into the DAC device for visual purposes. This eliminates it from a simple diagram and might result in something like this in a full diagram:

I can see how an argument can be made to consider a PCM270x a digital receiver for DACs with built-in USB support if you want it to be a requirement of the chain. In this case, it seems like a chain with say a Trends UD-10 to a Channel Islands VDA-2 would have two digital receivers (one in each device). In that case, I would still argue that the Trends is the "source/transport" rather than the USB host controller.

I'm also looking into where the content decoding occurs for a SqueezeBox chain. I think it can occur on either the server or the SqueezeBox, depending on the original content format (i.e. sends FLAC straight to SB to be decoded there, but transcodes Apple Lossless on the server prior to sending it to the SB).

 

[BradJudy]

I did some reading and it looks like the PCM270x family and similar devices definitely should be considered to have a digital receiver. This article was very good in learning about those devices: PlanetAnalog.com - The D/A diaries: A personal memoir of engineering heartache and triumph

Since the computer sees it as the audio output device, it still seems like it should also be considered the "source".

 

[FallenAngel]

I think it would be easier to think of a USB->S/PDIF converter as a transport, it's digital-digital. In my mind (which of course can work similar or different from others), the computer is the Source that reads data from the media and outputs a digital stream using the Transport to the receiver. The USB->S/PDIF, I would consider another transport in the chain.

Great photos by the way, thanks. I'll see what I can do about putting them on the first page, if you don't mind.

I'll get to it tonight.

 

[BradJudy]

Perhaps it's best to treat a USB->SPDIF like a Monarchy DIP, stand-alone upsampler, or other DSP-type device. It receives a digital signal and outputs a digital signal.

It sounds like I should change "source/transport" on my diagrams to simply "transport" for clarity. In effect, what I have called "content format decoder" is probably the layer you are referring to as the "source".

It's pretty quick and easy for me to tweak there and republish them if you let me know which styles are best. Do you feel that adding the arrows was good? Should the digital receiver always be shown as in the first diagrams or hidden as in the last? Does the word "source" have a concrete enough meaning to include in the diagrams?

 

[FallenAngel]

The split between Source and Transport might be a good idea in terms of the USB->S/PDIF converters and standalone up-samplers, but they are generally the "same" on soundcards and CD Players. Still a nice distinction I guess, good call.

I like "Content Format Decoder" notion as a "source" yet it doesn't exactly encompass the idea of a "source". To me, "source" means something that reads content (media) and spits out an unprocessed digital stream of it, guess that pretty much does mean decoder, but decoding might happen in other places, such as DSP or even beyond the digital receiver in terms of multi-channel audio or DSD. This will require a little thinking to clearly explain.

I'm sorry, I was swamped with things these last few days and didn't have a chance to put all the wonderful photos by BradJudy in the first page. Don't think I forgot about it or chose not to, I simply didn't get a chance to yet, completely plan to and am very grateful for such wonderful slides to visually display the components. Thanks! I'll try to have them up as soon as I have some time (likely not at work but after getting back from the gym, I should have an hour to dedicate to this).

Clarifications/Updates on the way.

 

[Ricey20]

Very informative thread so far. I like the colorful photos lol. Keep it up!

 

[dantztiludrop]

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif I like "Content Format Decoder" notion as a "source" yet it doesn't exactly encompass the idea of a "source". To me, "source" means something that reads content (media) and spits out an unprocessed digital stream of it, guess that pretty much does mean decoder, but decoding might happen in other places, such as DSP or even beyond the digital receiver in terms of multi-channel audio or DSD. This will require a little thinking to clearly explain.

I've been searching (unsuccessfully, so far) for this concept of "source" to be more clearly spelled out, but I was under the impression that the source was the point at which the digital signal is converted to analog.

 

[BradJudy]

Quote:

Originally Posted by dantztiludrop /img/forum/go_quote.gif I've been searching (unsuccessfully, so far) for this concept of "source" to be more clearly spelled out, but I was under the impression that the source was the point at which the digital signal is converted to analog.

The term "source" definitely seems hard to pin down. I spent some time browsing online "audiophile" dictionaries and write-ups on a few websites and no one bothers to define it. In the most general terms, it might be considered the sum of everything upstream from the amp/pre-amp. It's not clear to me that if you have a chain with a dedicated transport and a dedicated DAC if the word "source" should imply one, the other, or the sum of both.

Either way, it seems like it should be less specific than what was mentioned above (the reading of static content into an electrical signal - digital or analog).

 

[gregorio]

I think it's a good idea to be a little more specific with the term "source". After all, once we have a reasonable quality sound system, the quality of the original recording is at least of equal importance to any piece of equipment in the playback chain when it comes to sound quality.

G

 

[BradJudy]

Quote:

Originally Posted by gregorio /img/forum/go_quote.gif I think it's a good idea to be a little more specific with the term "source". After all, once we have a reasonable quality sound system, the quality of the original recording is at least of equal importance to any piece of equipment in the playback chain when it comes to sound quality.

I'm not sure what you mean. Are you saying that you use the term "source" to mean the content (CD, LP, mp3, etc)? Certainly the quality of the content is of the utmost importance, but I don't refer to it as the "source".

 

[gregorio]

Quote:

Originally Posted by BradJudy /img/forum/go_quote.gif I'm not sure what you mean. Are you saying that you use the term "source" to mean the content (CD, LP, mp3, etc)? Certainly the quality of the content is of the utmost importance, but I don't refer to it as the "source".

Professionally we use the term "source" or "source material" to mean the raw recorded tracks, before any processing or mixing is applied.

G

 

[dantztiludrop]

A year or so ago there was a thread (probably has been a bunch of them) where this concept of source was raised. A few people were very set on the idea of source being defined as "the point of origin of analog along the path", with everything before that being "transport". I've just always believed them & went with that definition....but who knows(?).

And I'm not sure, gregorio, how that fits into the realm of a professional recording system.

 

[gregorio]

Quote:

Originally Posted by dantztiludrop /img/forum/go_quote.gif A year or so ago there was a thread (probably has been a bunch of them) where this concept of source was raised. A few people were very set on the idea of source being defined as "the point of origin of analog along the path", with everything before that being "transport". I've just always believed them & went with that definition....but who knows(?). And I'm not sure, gregorio, how that fits into the realm of a professional recording system.

Of course, that wouldn't really work with a recording system because then source would pretty much at the end of the chain rather than at the beginning. I would agree with "the point of origin of analogue along the path" but of course in recording this is the point from the musician performing up to the signal exiting the mic-preamp and entering the ADC.

We could agree to have a meaning for source here and different meaning for recording. It would likely lead to some confusion though!!

G

 

[Aleatoris]

Why hasn't this been stickied yet?