exaU2I - Multi-Channel Asynchronous USB to I2S Interface - Page 107 - diyAudio
Go Back   Home > Forums > Commercial Sector > Manufacturers > exaDevices

exaDevices World-class audio devices for do-it-yourself projects from exaDevices

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 27th March 2012, 11:27 AM   #1061
diyAudio Member
 
Join Date: Jun 2004
Location: Bath, UK
Quote from Mathias (RME designer):

"Its most spectacular feature is the addition of multi-client mixing. You can now use any number of programs of any sort (WDM, ASIO) to play back on the same channels. Note that as long as you use only one program per playback channel the driver works as before, including bit-perfect playback."
  Reply With Quote
Old 27th March 2012, 01:04 PM   #1062
diyAudio Member
 
Join Date: Jun 2005
Location: Texas
Quite frankly, as a happy exaU21 owner, I would rather see George continue to spend his time on new and continued product/feature development.
__________________
www.affirmaudio.com
  Reply With Quote
Old 27th March 2012, 02:10 PM   #1063
oyvine is offline oyvine  Norway
diyAudio Member
 
Join Date: Sep 2005
Location: Trondheim
Quote:
Originally Posted by drspence View Post
Quite frankly, as a happy exaU21 owner, I would rather see George continue to spend his time on new and continued product/feature development.
Hallelujah!
It might also be a good idea to spend some time into marketing/documentation to gain some more customers(me for instance). I do not understand what sets the exa apart in "bit-perfectness". Therefore I do not "buy" that argument. A white paper could perhaps convince me and bring me on board. Undocumented claims tends to do the opposite.

regards,
ōyvin
  Reply With Quote
Old 27th March 2012, 02:58 PM   #1064
diyAudio Member
 
Join Date: Jun 2004
Location: Bath, UK
I thinks we might have some crossed wires here.

I presumed exa was discussing bit-perfect in regard to his USB to I2S converter and comparing that to RMEs spdif output.

I now see he may have been referring to his new DAC product and comparing that to RMEs DACs. This is a whole different kettle of fish However, beyond 16bit AFAIK, there are no DACs that can truly be called bit-perfect. If his new product achieves this then it is quite an achievement indeed - I look forward to evidence of this being the case.
  Reply With Quote
Old 27th March 2012, 03:14 PM   #1065
ccclapp is offline ccclapp  United States
diyAudio Member
 
Join Date: Mar 2012
Quote:
Originally Posted by oyvine View Post
Hallelujah!
It might also be a good idea to spend some time into marketing/documentation to gain some more customers(me for instance). I do not understand what sets the exa apart in "bit-perfectness". Therefore I do not "buy" that argument. A white paper could perhaps convince me and bring me on board. Undocumented claims tends to do the opposite.

regards,
ōyvin


As I understand it the rme and many other sound devices will output bit perfect audio streams . I believe the issue is that there can be significant jitter and/or noise. Many people feel that using a USB or FireWire interface to the ps can yield far less of both. Many people feel that using a i2s interface between the USB and the DAC is optimal for similar reasons. Many people feel the b-III is an excellent DAC. Exa's u2i interface card is the only way I know of to bring all of these things together in m-ch.


"Quote:
Originally Posted by exa065
...It was discussed in previous posts in this thread, you can browse back and read it.
This thread is 106 pages(!) It would be useful if you took the time to write a white paper or something to explain this issue in detail and what exaU21 does to overcome it. "...

I believe the discussion he was referring to began 1 page back and is the same discussion you have joined in on.


"It might also be a good idea to spend some time into marketing/documentation"...

Likely everyone would agree more documentation would make all of our lives easier. This statement applies to this card, the buffalo-III and in fact the whole DIY experience of which both are a part. But then again I guess that's why it's called DIY ;-)
  Reply With Quote
Old 27th March 2012, 03:36 PM   #1066
ccclapp is offline ccclapp  United States
diyAudio Member
 
Join Date: Mar 2012
oyvine ,

Here is one of many threads on a site you may find helpful: computeraudiophile.com

Music player: what is there beyond Bit Perfect'ness? | Computer Audiophile
  Reply With Quote
Old 28th March 2012, 09:22 AM   #1067
oyvine is offline oyvine  Norway
diyAudio Member
 
Join Date: Sep 2005
Location: Trondheim
Quote:
Originally Posted by ccclapp View Post
"Quote:
Originally Posted by exa065
...It was discussed in previous posts in this thread, you can browse back and read it.
This thread is 106 pages(!) It would be useful if you took the time to write a white paper or something to explain this issue in detail and what exaU21 does to overcome it. "...

I believe the discussion he was referring to began 1 page back and is the same discussion you have joined in on.
This discussion has been going on for a while. Periodically I see claims such as in this posting:
exaU2I - Multi-Channel Asynchronous USB to I2S Interface
"I may say as much as when a 16 bit audio file are played and the so called bit-perfect chain to the DAC are following the standards - then you may get bit-perfect performance ONLY if you use a pure 16 bit DAC.."

I have also seen a posting where the actual C-library that is used was mentioned. I am not able to find it at the moment though. According to RayCtech, the exa065 and its drivers converts 16-bit data to 24-bit data in a "bit-perfect" way. I would really like to get some understanding on what this means and also understand why and how "all others" fail to do this correctly.

regards,
ōyvin Eikeland
  Reply With Quote
Old 28th March 2012, 11:11 AM   #1068
Marek is offline Marek  Poland
diyAudio Member
 
Join Date: Apr 2003
Location: Katowice
Quote:
Originally Posted by oyvine View Post
According to RayCtech, the exa065 and its drivers converts 16-bit data to 24-bit data in a "bit-perfect" way. I would really like to get some understanding on what this means and also understand why and how "all others" fail to do this correctly.
its simple - you add 8 zeros as 8 LSBs to 16-bit word and you get 24-bit word with 16 MSBs untouched.
When you use for example digital filter or ASRC with 24-bit output length the input word is recalculated and 16 MSBs of 24-bit output word are not the same as 16 MSBs of input word
  Reply With Quote
Old 28th March 2012, 02:15 PM   #1069
diyAudio Member
 
Join Date: Apr 2004
Location: Wisconsin
Default Connecting to a Micro Controller

I am trying to figure out the best way to input the bit rate into a micro controller. I know I would have to remove the LED's on the exaI2S. I have a lot of experience with the micro controller and basic digital IO. I am having trouble figuring out the best way to do this interface. The Xilinx chip that controls the LED's is new to me and I am having trouble getting what I need from their documentation. One idea I had was to use optical isolators. But they can draw 60ma. Is this too much for the Xilinx? I want to be careful with my investment in the exa board.
  Reply With Quote
Old 29th March 2012, 01:43 AM   #1070
exa065 is offline exa065  Canada
diyAudio Member
 
Join Date: Feb 2011
Quote:
Originally Posted by johnmarkp View Post
I am trying to figure out the best way to input the bit rate into a micro controller. I know I would have to remove the LED's on the exaI2S. I have a lot of experience with the micro controller and basic digital IO. I am having trouble figuring out the best way to do this interface. The Xilinx chip that controls the LED's is new to me and I am having trouble getting what I need from their documentation. One idea I had was to use optical isolators. But they can draw 60ma. Is this too much for the Xilinx? I want to be careful with my investment in the exa board.
Hi John,
You can replace the LEDs with optical isolators. The FPGA outputs are connected via 390 Ohms resistors, so you can draw about 5-6 mA.

George
__________________
exaDevices.com | exaSound.com
  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
Ultimate USB to I2S interface sampler Digital Source 206 30th January 2012 04:45 PM
High Resolution Multi-Channel Digital Interface Brian Brown Digital Source 34 15th January 2008 07:48 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 11:06 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