XMOS-based Asynchronous USB to I2S interface - Page 73 - diyAudio
Go Back   Home > Forums > Source & Line > Digital Source

Digital Source Digital Players and Recorders: CD , SACD , Tape, Memory Card, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 14th May 2012, 02:01 PM   #721
PET-240 is offline PET-240  Australia
diyAudio Member
 
Join Date: Feb 2010
Location: Brisbane Northside
Default CONGRATULATIONS!

G'day ENSen,

Congrats on the little one, hope both are well and happy!

You have a pm reg the Alix, I have one arrived in the box the other day, still getting that sorted!

God Bless!

Drew.
  Reply With Quote
Old 14th May 2012, 02:16 PM   #722
diyAudio Member
 
Join Date: Nov 2007
Location: Scotland
Quote:
Originally Posted by triode_al View Post
So I don't understand your complaining.
I wasn't complaining about anything, merely trying to suggest that the notion of "custom" drivers seems a bit arbitrary to me and thus unhelpful even if soundchekk disagrees. (He of course has the benefit of Linux expertise.)

To revert to topic, I have no issue with buying a device that uses Thesycon drivers - they may not be "stock" but they are certainly mainstream and much more likely to be refined over time and kept current than any drivers supplied with XP (or Vista or Win 7 or Win 8 or . . . ).
  Reply With Quote
Old 14th May 2012, 03:48 PM   #723
diyAudio Member
 
Join Date: Jul 2010
Default Windows/OSX

"There's now a thriving market in after-market (custom?) players for the Mac with users anguishing over soundstage (depth, width and height all according), "inner detail", ambience and all the rest with a zeal that makes some of us PC wallahs queasy."

With ASIO, and W7, many of the previous "problems" of Windows with audio are solved, and this brings W7 to the level of OSX regarding software, but hardware is another story...

I would not get queasy... It appears that a good W7 set up is now on a close to level playing field with OSX for sound quality: that is, better try jPlay if you want the best performance (or HQplayer, etc for tweaky options).

My experience is that better audio quality is going to result from a low power computer server running linux (vs W7 or OSX), voyage/mpd in my case. But my experience may be hardware related, as my custom server has a low noise dedicated USB output card running on an isolated linear power supply.
  Reply With Quote
Old 14th May 2012, 07:42 PM   #724
jrling is offline jrling  United Kingdom
diyAudio Member
 
Join Date: Jan 2010
Location: London England
Quote:
Originally Posted by barrows View Post

With ASIO, and W7, many of the previous "problems" of Windows with audio are solved, and this brings W7 to the level of OSX regarding software, but hardware is another story...
I would be interested to hear what improvements were made by MS in W7 to their audio software that you are basing that statement? Genuinely interested, as I run W7 am v happy with it. But they still do not support USB Audio Class 2 in W7 or I believe Windows 8.

Thank you
  Reply With Quote
Old 14th May 2012, 08:28 PM   #725
rsdio is offline rsdio  United States
diyAudio Member
 
Join Date: Feb 2008
Location: Seattle
Great questions. I'll try to answer where I can.

Quote:
Originally Posted by Ryelands View Post
Sorry if I'm being dumb but I can't follow your argument here. What's the essential difference between a USB designer who develops his/her own firmware and drivers on the one hand and one who licences from the likes of Thesycon or Ploytek on the other? (Except of course that the latter are likely to be much cheaper and give the designer access to significant expertise.)
I would say that licensing code is orthogonal to USB Audio Class compliance. The choice to license should not force the choice to comply with standards. I probably should have been more precise in my terminology. Thus, if you don't understand my argument then it's probably my fault!

I am not familiar with the offerings of Thesycon or Ploytek, but if either of them offer UAC firmware and/or drivers then there is nothing wrong with paying for a license versus paying for firmware or driver development in-house. Firmware development is often handled by a different engineer than the hardware design, and so there's certainly nothing wrong with licensing firmware from a third party. Same thing goes for the driver that lives on the computer.

The biggest issue is that Mac OS X supports USB Audio Class with a system driver, whereas Windows does not (to my knowledge). This means that hardware developers targeting Windows are forced to develop a Windows driver as well as their device firmware. My comments were that when a hardware developer fails to create a UAC compliant firmware in order to make their custom driver easier to develop, they've done a disservice to their customers and have made any OSX customers deal with unnecessary third-party system drivers.

Quote:
Also, taking your word on the fact that the USB Audio specs are all-inclusive (I've read some of them but not carefully), I don't see how it follows that Apple's implementation of those specs is, as you seem to imply, perfect almost by definition.
It's not rocket science. It either works or it doesn't. I'm not saying that Apple is "perfect" so much as I'm saying that it works. I mean, nobody questions whether USB hard drives work "better" on Apple or Microsoft systems. The fact is that when you save a file to a USB drive, your files are bit-perfect whether you're working on Mac or PC. The same should be true for audio, except that Windows does not provide USB Audio Class drivers and OSX does.

So, I turn this question around to you: Are you implying that we should be concerned about whether Apple's USB Storage Class (disk drive) code is "perfect?" Should we be pitting USB hard drive reliability under Windows against the same drive under OSX? If not, then why would there be a vendor battle over USB Audio, except for the fact that Microsoft isn't even trying.

I simply expect it to work as reliably for audio as it does for a file storage device. I've gone so far as to confirm that the audio data is bit-perfect on a Mac, but to be honest those exhaustive tests have been for FireWire Audio more than USB Audio. I just don't see any reason to doubt that it's perfect. On Windows, there is no USB Audio Class driver, so I'm not saying that Microsoft couldn't do an equally perfect implementation, I'm merely acknowledging that they haven't tried (or haven't released anything).

Quote:
The notion that Apple's audio software was, unlike those clunky PCs, as good as it could ever be was aired almost daily by a small group of Mac users on AA's computer audio forum a year or two back. It took a knock when a music-player program called Amarra - which cost more than my entire PC audio system (inc custom driver . . .) - was released.

There's now a thriving market in after-market (custom?) players for the Mac with users anguishing over soundstage (depth, width and height all according), "inner detail", ambience and all the rest with a zeal that makes some of us PC wallahs queasy.
We're not going to get anywhere with this line of discussion, because those same users probably think that changing the power cord on their computer changes the sound stage. In my estimation, it is impossible for "those" people to ever be satisfied with anything. There will always be snake oil that makes the best technology "better."

Quote:
Granted, a few iTunes devotees (curiously, mostly programmers) can still be heard muttering under their breath from time to time but the emerging consensus is that Macs are prone to much the same issues as PCs once the user starts to push the boundaries.
I use iTunes and get bit-perfect performance out of it. I have designed hardware tests to confirm that the bits reaching my DAC are exactly the same bits in my audio files, and I know that the clocking is controlled by my DAC, not by iTunes, CoreAudio, OSX, or anything on the computer (which is slaved to the DAC).

Granted, I'm always learning new things, and I would love for someone to prove the merits of Amarra to me. At this time, I do not see the point. Then again, I have Logic and my own audio software for those times when I doubt iTunes' quality.

Quote:
In short, I'm not saying you're wrong but I'm not convinced you're right either.
I'm struggling with staying on topic versus making a convincing argument that encompasses all possible questions. The challenge is to be concise without leaving holes that raise questions. Hopefully, a conversation that isn't one-sided will be most informative.
  Reply With Quote
Old 14th May 2012, 09:01 PM   #726
diyAudio Member
 
Join Date: Jul 2010
Default Well...

As most of the aftermarket playback software available allows for free trials (Amarra, Pure Music, etc) if you are interested in improving the playback performance of your system, it is quite simple for YOU to test for yourself.
Yes, you can get bit perfect playback from Itunes.
But, it is not up to anyone to "prove" anything about the sonic benefits of different playback software, it is simple enough for people to try it for themselves, for free, and come to their own conclusions about the sonic benefits.
I prefer to make decisions for my system based on what I hear, not what someone on the internet might tell me I "should" hear, and I suggest that you might want to do the same. Why not, considering it is free to find out...
  Reply With Quote
Old 14th May 2012, 09:12 PM   #727
Wolfsin is offline Wolfsin  United States
diyAudio Member
 
Join Date: Aug 2009
Blog Entries: 2
Everyone agrees the i2s bits from WaveIO are bit-perfect. At issue, it appears, is jitter. Given the stock WaveIO being shipped by Lucien today, using external power but not modified to accept an external clock, is the jitter of the PCM stream affected by which OS is supplying the bits?

This thread is about WaveIO. If the answer to the above is that macs, linux, and windows machines all suffer the same jitter then everything about any application running on any OS is OT because the few picoseconds of measured jitter is inherent in the WaveIO clock.
__________________
'gardz, Dick

Last edited by Wolfsin; 14th May 2012 at 09:19 PM.
  Reply With Quote
Old 14th May 2012, 10:31 PM   #728
rsdio is offline rsdio  United States
diyAudio Member
 
Join Date: Feb 2008
Location: Seattle
Quote:
Originally Posted by Wolfsin View Post
Everyone agrees the i2s bits from WaveIO are bit-perfect. At issue, it appears, is jitter. Given the stock WaveIO being shipped by Lucien today, using external power but not modified to accept an external clock, is the jitter of the PCM stream affected by which OS is supplying the bits?
No.

According to the web site, WaveIO is based on a reference design that is a High Speed USB 2.0 Device that implements Audio Class 2.0 (and 1.0) using asynchronous synchronization. Thus, although the WaveIO master clock may not be perfect, it is not controlled by the OS or the USB Host computer. Using external power, there is very little, probably no opportunity for the computer to affect the on-board clock. In other words, the only way to improve the clock jitter reliably is to change the hardware, not the OS.

Quote:
This thread is about WaveIO. If the answer to the above is that macs, linux, and windows machines all suffer the same jitter then everything about any application running on any OS is OT because the few picoseconds of measured jitter is inherent in the WaveIO clock.
Thank you for focusing the discussion on the purpose of this thread.
  Reply With Quote
Old 14th May 2012, 10:35 PM   #729
Telstar is offline Telstar  Italy
diyAudio Member
 
Join Date: Dec 2007
Location: Italy
Quote:
Originally Posted by barrows View Post
My experience is that better audio quality is going to result from a low power computer server running linux (vs W7 or OSX), voyage/mpd in my case. But my experience may be hardware related, as my custom server has a low noise dedicated USB output card running on an isolated linear power supply.
I'm going to try this on my office w7 computer.
__________________
"The total harmonic distortion is not a measure of the degree of distastefulness to the listener and it is recommended that its use should be discontinued." D. Masa, 1938
  Reply With Quote
Old 14th May 2012, 11:55 PM   #730
diyAudio Member
 
Join Date: Jul 2010
Default Well...

"According to the web site, WaveIO is based on a reference design that is a High Speed USB 2.0 Device that implements Audio Class 2.0 (and 1.0) using asynchronous synchronization. Thus, although the WaveIO master clock may not be perfect, it is not controlled by the OS or the USB Host computer. Using external power, there is very little, probably no opportunity for the computer to affect the on-board clock. In other words, the only way to improve the clock jitter reliably is to change the hardware, not the OS."

Consider, that even when supplying a separate power supply for the USB interface, the computer ground is still connected to the WaveIO ground, and hence the computer's ground is connected to the ground of the oscillator's. It is entirely possible (likely) that noise on the computer's ground does raise the jitter level becuase of this connection.

But, I also think there is more to this than just jitter and bit perfection. I suspect that noise from the computer will couple through the WaveIO interface and into the DAC, perhaps even into the analog circuitry of the DAC. The folowing is speculation: it may be that better playback software allows the computer to run with less noise (most playback software developers remark that their software reduces processor load) and less noise then gets into the output of the DAC. This factor would also be a possible explanation for why low power computers often sound better.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
exaU2I - Multi-Channel Asynchronous USB to I2S Interface exa065 exaDevices 1357 3rd March 2014 09:51 PM
Introducing miniStreamer: Native 24/96 USB to I2S / SPDIF interface minidsp miniDSP 39 6th January 2014 12:00 AM
Ultimate USB to I2S interface sampler Digital Source 206 30th January 2012 04:45 PM
Is it possible to develop a ASIO driver for PCM2900 based USB Audio interface? cxhawk Digital Source 7 3rd December 2010 03:30 PM
interface I2S with USB mermoz Digital Source 0 21st February 2003 11:34 AM


New To Site? Need Help?

All times are GMT. The time now is 07:58 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2