Pc -> Dac, How ?

[Goto]

That looks bsically like ethernet streaming...

[philpoole]

audio synthesis used two ST channels: http://www.audiosynthesis.co.uk/dax_discrete5.htm Anyway, i dont think i2s is a bad interface, if implemented well.

That just looks like marketing snake-oil.
I'm sure ST is a very good interface, but to argue that I2S adds a square wave in the audio frequency domain is a red-herring.
I assume its referring to the WS signal, which could potentially be classed as audio frequency at the sampling frequency, just (correct me if I've missed the point).

This is a pointless argument to make for ST being superior, because whatever link you use, you'll need to convert back to I2S (or very similar) to be able to feed the digital signal to your chosen DAC, so you'll be re-inserting this audio component anyway. AND, you'll be having to convert to ST (which is also a conversion from electrical to optical) and then back to the original I2S-esque signal, each conversion an opportunity to add jitter.

I think it seems hi tech because its optical.

Just my opinion though, I'm not after an argument.

[rfbrw]

Originally posted by peufeu

Ah, rfbrw, always so cheerful no topic would be complete without your snide remarks.

Least I could do, it's Christmas.
Would it not be more useful to have titled the thread "Improved PC based USB Audio output" or something similar as the "How" bit was clearly decided long before finger hit keyboard. The rationale of this thread escapes me.

[Pjotr]

Anyway rfbrw, it escapes me at all what peufeu is up to. FW and USB2 DAC’s with their own lo-noise x-tal oscillator are readily available at the corner of the street. And if you wish you can drop in a holy TENT-clock for even lower jitter. And modify as heavily as you wish the PSU for lowest noise.

FW, USB2 and Ethernet (either wired or wireless) have plenty of bandwidth to get the audio data at the DAC-chip on a regular package/handshake basis.

And if you wish isolation between PC and DAC with USB2, put an USB isolator in between (not cheap though).

[Telstar]

Originally posted by rfbrw
Would it not be more useful to have titled the thread "Improved PC based USB Audio output" or something similar as the "How" bit was clearly decided long before finger hit keyboard.

ditto.

[wakibaki]

Originally posted by rfbrw
The rationale of this thread escapes me.

My take on it:-

Of the first post 90% is about how clever the author is and the technologies he claims to understand with a 10% sweetener about the wonderful things he's gonna do for us, all brewed up into a condescending slurry of buzzwords.

While I can see that the writer might be able to string together a few lines of Python, I can't see how anybody whose post is so fragmented and disorganised could possibly do anything useful in VHDL.

If you've just explained something carefully and in detail, than there's some justification in offering the encouragement that 'it's easy', but in this case it's just an attempt to dump on people who might be struggling with such very issues.

You're an expert are you? Go on, do me something expert then...

w

[audioengr]

Peufeu has it right. USB 2.0 async interface supporting 24/192 is the ticket. This is exactly what I'm doing in 2009.

Steve N.

[abraxalito]

Originally posted by wakibaki

My take on it:-

Of the first post 90% is about how clever the author is and the technologies he claims to understand with a 10% sweetener about the wonderful things he's gonna do for us, all brewed up into a condescending slurry of buzzwords.

Get thee to a therapist. Peufeu is clearly a smart guy, if you have a problem with that then your inferiority complex is a matter for your shrink, not this forum.

While I can see that the writer might be able to string together a few lines of Python, I can't see how anybody whose post is so fragmented and disorganised could possibly do anything useful in VHDL.

Ah, so you think you know how good a person's VHDL skills are from their postings on diyaudio. That's laughable. I'll bet peufeu is (or becomes) good enough at VHDL to make his project work - then will you eat humble pie?

If you've just explained something carefully and in detail, than there's some justification in offering the encouragement that 'it's easy', but in this case it's just an attempt to dump on people who might be struggling with such very issues.

If you're one of those who is struggling with the issues, then ask. I reckon that peufeu will take time to answer your questions. But if you don't ask, you'll not receive. In point of fact, on his website he does go to quite great lengths to explain things, so he's not just parading his knowledge as you seem to think.

You're an expert are you? Go on, do me something expert then...

w

Just take a look at peufeu's website, he clearly shows he's a competent engineer - he's an original thinker and he gets results. What problem do you have with that?

R

[peufeu]

Let's make a summary of this thread...

I'd like to know what others think / try / have tried and their experiences about connecting a PC to a DAC the correct way (something about clocks...) so I open a topic. Some people bring useful information like dw8083 who has his hands on DSPs (interesting). Then a debate on FireWire ensues with half of the people who don't know what they're talking about, as usual

This detracts from the useful stuff :

- what did dw8083 do with his DSP ? will you implement a digital crossover/EQ on that ?

- what setup is schro20 using, what Roku's is he talking about ?

- what could this phrase by tritosine mean
"Also, you seem to forgot that the TI / BB chips have direct downsampling option, the data is not harmed by downsampling filter that way."

- what happened to rfbrw so he has to take his emotional issues out on an audio forum ? must be pretty nasty stuff...

> Would it not be more useful to have titled the thread "Improved PC
> based USB Audio output" or something similar as the "How"
> bit was clearly decided long before finger hit keyboard.
> The rationale of this thread escapes me.

Yeah perhaps it should. Or not. Perhaps the title should have been "trolls versus people" ?

> Of the first post 90% is about how clever the author
> is and the technologies he claims to understand

You mistook enthusiasm for snobbery. My bad. I should have put a disclaimer.
Actually I wanted to post more explanations later but this was cancelled due to too much trolling.

> I can't see how anybody whose post is so fragmented and disorganised
> could possibly do anything useful in VHDL.

You're right, I suck at VHDL, I much prefer Verilog. I would be curious to know what you know about VHDL though.

> If you've just explained something carefully and in detail, than there's
> some justification in offering the encouragement that 'it's easy', but in this
> case it's just an attempt to dump on people who might be struggling with
> such very issues.

Considering the amount of trolling that happens here, you will, I hope, understand that I like to waste a minimum of time writing on this forum.

You could have asked instead of being insulting.

When I say "USB is simple", it means the amount of knowledge needed to make it working is small. Ethernet is simple, too. On the opposite, FireWire is complex. From opening the FX2 datasheet and google to getting streaming to work, it took a few evenings, and I knew nothing about USB before that. I still don't know much about USB, that's why I chose bulk and not async isochronous to start with. FX2 is a very simple chip too, the hardware does everything, I like this chip.

If you were interested in the subject, instead of just ranting, you would have opened a Cypress app note and seen for yourself.

Originally posted by audioengr
Peufeu has it right. USB 2.0 async interface supporting 24/192 is the ticket. This is exactly what I'm doing in 2009.
Steve N.

Want to join ?

The project will be opensourced as soon as it's ready, I think I'll put it on OpenCores. I would have liked an opensource USB soundcard with good quality, eq, crossover, custom oversampling etc. Since it doesn't exist, I'm building it. Those who want to help are invited

Thanks to abraxalito for reading my posts.

Oh and by the way, don't think I'm pissed by the trolling. It's pretty funny actually.

[Telstar]

Originally posted by peufeu
Want to join ?

Considering how much he charges for the commercial dacs i dont think that Steve would be interested in an open source project.

The project will be opensourced as soon as it's ready, I think I'll put it on OpenCores. I would have liked an opensource USB soundcard with good quality, eq, crossover, custom oversampling etc. Since it doesn't exist, I'm building it. Those who want to help are invited

While I do think that you are a very skilled and smart person, I also think that are way too many usb dacs already available and that they either sound crappy or are very expensive, or both.
So, being usb the interface of choice, my interest in the project is nil.

I wish you all the luck in solving the several problems due to this interface that you will find along the way.