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Old 1st November 2011, 07:33 AM   #141
rsdio is offline rsdio  United States
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Quote:
Originally Posted by Turbon View Post
I would say that firewire is dead from the industrys point of view. No interest - no money.
You can say whatever you like. Meanwhile, high-end audio companies continue to release products based on FireWire.

UAD just announced this month a FireWire-based DSP accelerator card - one that should be very attractive to folks wanting to perform biamping EQ without the hiccups of running under a generic operating system.

Metric Halo Labs released their LIO-8 FireWire audio interface last year, and are winning awards this year as probably the best DAC on the planet.

These are not the cheap USB Audio interfaces that your grandma buys at Fry's. It's a totally different ball game.

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I do understand what you are writing rsdio but to be able to hear the timing imperfectness you need a constant error in your data chain. It can't show itself as something happening here or there.
Sorry, but you're wrong. Jitter is random timing fluctuations, and it is audible as an increased noise floor at best or correlated distortions at worst. Jitter introduces analog errors tens of thousands of times per second. So, it's 'constant' in the sense that it is happening all the time, but it's not literally constant because the timing error is different with every sample.

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Finally, don't worry about violating the standards as they have 2 sides. The lesser thought of is that it keeps you boxed so that you can't perform better than your competitors.
Thanks for the encouraging words!
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Old 1st November 2011, 08:31 AM   #142
Turbon is offline Turbon  Sweden
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Hmmm, how do you multiquote?

Quote:
Originally Posted by rsdio View Post
You can say whatever you like. Meanwhile, high-end audio companies continue to release products based on FireWire
.
I usually say whatever I like :-)

UAD just announced this month a FireWire-based DSP accelerator card - one that should be very attractive to folks wanting to perform biamping EQ without the hiccups of running under a generic operating system.

Metric Halo Labs released their LIO-8 FireWire audio interface last year, and are winning awards this year as probably the best DAC on the planet.

These are not the cheap USB Audio interfaces that your grandma buys at Fry's. It's a totally different ball game.

Yes, dead was an overstatement - sorry. But the target is moving from the home to the professional domain. There is little interest from the broad market.

Sorry, but you're wrong. Jitter is random timing fluctuations, and it is audible as an increased noise floor at best or correlated distortions at worst. Jitter introduces analog errors tens of thousands of times per second. So, it's 'constant' in the sense that it is happening all the time, but it's not literally constant because the timing error is different with every sample.

If it is as bad as you describe - of course it affects the sound. What was these people thinking of when they created the standards?


Thanks for the encouraging words!
Don't mention it. People like me getting the best out of smart people as you is called progress ;-)
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Old 1st November 2011, 09:06 AM   #143
Turbon is offline Turbon  Sweden
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Now to the QUESTION in capital letters.

Does it work? What tweaks if any needs to be done?

Brgds
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Old 1st November 2011, 09:44 AM   #144
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Hello guys,
back from a short trip... I see things are getting wild here There's a lot to chatch up for me thus I'll try to share my opinions one at a time... hoping I'll not ruin the thread
WaveIO must be redesigned, main goal being the need to isolate things there (and I'm speaking about I2S). On my perspective, digital (noisy) ICs must stay on one side of board while sensitive/analog ones on the other side. Besides that, I saw how "sensitive" the XMOS reference design is (mostly in software) thus I'll try to keep this implementation close to original as possible (for obvious reasons)... meaning that, from the hardware point of view, I'll not place any isolator between the XMOS and PC/MAC. I'm tired about BSODs and other "fancy" behaviours without them.
On the other hand, I2S must be isolated somehow and now, I'm thinking how to do this without getting too much jitter on the path. One solution could be to realign all the I2S signals at the DAC side but for now it's in prototyping stage...
Cheers,
L
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Old 1st November 2011, 09:48 AM   #145
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Quote:
Noise on the USB data lines can be mitigated with a common-mode choke designed for such an application. Murata makes one.
@ abraxalito Could you share the serial number on that part? I saw it in the past... if memory serves me right, on one of their app note or product specs ... but I can't remember where.
L
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Old 1st November 2011, 12:05 PM   #146
rsdio is offline rsdio  United States
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Quote:
Originally Posted by Turbon View Post
Hmmm, how do you multiquote?
HTML Code:
I manually insert [/quote] and [quote]
(end quote and begin quote)
in the larger quoted text
anywhere that I want to comment,
then I type my responses in between
Quote:
If it is as bad as you describe - of course it affects the sound. What was these people thinking of when they created the standards?
It was so long ago that I don't know. Certainly before my time as a professional, although I was curious at the time. I get the impression that they really were not aware of the effects of jitter. I certainly did not understand until I attended an AES meeting where someone demonstrated it in real time with frequency analyzers connected to the output of a CD player. Part of the issue is that it's cheaper to omit a quality master clock, but the original standards seem more like they were completely oblivious rather than just cutting costs.

I met one digital audio circuit designer who admitted that he did not realize the importance of the layout of traces and other esoteric aspects of the clock design until someone demonstrated the improved clarity of the sound. Afterwards, he put way more effort into every board design, and the company's products were all the better.

One innocuous aspect is that if the spectrum of the jitter noise is Gaussian, then it really just adds noise that reduces the effective bit depth. Unfortunately, it's far more common that the jitter noise has some unnatural spectral quality that is correlated to the data in a way that sounds really harsh.
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Old 1st November 2011, 12:11 PM   #147
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Originally Posted by barrows View Post
"Noise, from the computer transmitted by the USB cable, and noise from the XMOS processor itself CAN increase jitter at the DAC-this is why people want galvanic isolation from the computer. How much jitter can this cause? I have not seen or heard of anyone measuring this..."
Whether it DOES is on a case by case basis.

Until somebody measures it on a comparative basis it hasn't been demonstrated that it CAN in any case.

You've got NO IDEA what constitutes evidence.

You just make these claims, not even realising that you invalidate them in the next sentence. You need to learn to think about what you yourself have written. The overall contribution of your statement is noise.
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Old 1st November 2011, 12:22 PM   #148
rsdio is offline rsdio  United States
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Originally Posted by counter culture View Post
You need to learn to think about what you yourself have written. The overall contribution of your statement is noise.
kettle := BLACK == pot
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Old 1st November 2011, 12:23 PM   #149
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Quote:
Originally Posted by Lorien View Post
Could you share the serial number on that part?
This is one of their most helpful documents - the USB component recommendations start on page 12:

http://www.murata.com/products/catalog/pdf/c35e.pdf
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Old 1st November 2011, 12:26 PM   #150
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Originally Posted by rsdio View Post
kettle := BLACK == pot
If you have something specific to say, make your point.
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