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Old 7th April 2011, 11:39 PM   #281
SunRa is offline SunRa  Romania
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Quote:
I am curious to why not those that have received and evaluated the exaU2I are writing about their experiences here??

Have all the exaU2I units been sold to competitors of exaDevices

I cannot be the only one that have managed to connect the exaU2I and have it running as I now have connected it to several DAC in several ways and it have worked every time without any issues...
Just a few hours ago I managed to finish building a battery powered DAC around AK4396 and test the exaU2I. Listening to some of the high resolution files I've gathered over time, I felt the entire project was very rewarding.

Everything was smooth in installing the exaU2I, driver and player set-up is straightforward, also the connection to various DAC's is easy to get right, even for a beginner.

It quickly became obvious that I was hearing more details than my 96Khz capable soundcard and that it is clearly over a PCM2706 interface I built some time ago. I will come back with some more details, right now I just want to enjoy some music .

Anyhow, this board clearly is of great value considering that technologically is quite advanced. It's great to have the possibility of turning your PC into a digital crossover without the need of other conversion stages as it happens with Behringer for example. Also I plan to experiment soon with 32 bits material on an AK4397/99.
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Old 8th April 2011, 12:08 AM   #282
rsdio is offline rsdio  United States
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Originally Posted by Marek View Post
My knowledge about FW audio support is poor but as you said FW has isochronous mode defined which is not what we want. In isorchonous mode data source (PC) is a clock master like with PCM270x. If we want achieve lowest possible jitter , clock source (precise low jitter XO) should be located close to DAC and this requirement is the main reason for creating exa2UI.
I do not know FW solutions you talking about but I'm not sure it offers best best jitter performance which we want here.
I realize that I replied to this already, but I ignored the details of USB.
Isochronous does not mean what you think it means. Grab the USB Specifications from USB.org and read about USB-Audio and USB 2.0 in general. You will find that there are three Audio Synchronization Types (Chapter 3.3 in the USB-Audio Specification): Asynchronous, Synchronous, and Adaptive. All three of these use Isochronous endpoint data transfer packets. So, you are basically wrong about how USB works. I'm sure you probably read the term 'isochronous' in some online article which used a different definition, and that's probably why you got confused. When in doubt, the USB Specifications are freely available for reference.

To reiterate, neither FireWire nor USB have any problem running the DAC chip as master clock over an isochronous connection. In fact, all commercial audio interfaces use isochronous data transfers, because the data must be delivered in real time, unlike a hard drive.
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Old 8th April 2011, 01:33 AM   #283
AR2 is offline AR2  United States
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Quote:
Originally Posted by SunRa View Post
Just a few hours ago I managed to finish building a battery powered DAC around AK4396 and test the exaU2I. Listening to some of the high resolution files I've gathered over time, I felt the entire project was very rewarding.

Everything was smooth in installing the exaU2I, driver and player set-up is straightforward, also the connection to various DAC's is easy to get right, even for a beginner.

It quickly became obvious that I was hearing more details than my 96Khz capable soundcard and that it is clearly over a PCM2706 interface I built some time ago. I will come back with some more details, right now I just want to enjoy some music .

Anyhow, this board clearly is of great value considering that technologically is quite advanced. It's great to have the possibility of turning your PC into a digital crossover without the need of other conversion stages as it happens with Behringer for example. Also I plan to experiment soon with 32 bits material on an AK4397/99.
Thank you for the brief report. Would you mind elaborating on what are you using on the software side, what player, crossover app (if any) etc. That way we could have a more complete picture of what the set up is.
I am looking forward to learn more about your results.
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Old 8th April 2011, 07:44 AM   #284
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Originally Posted by SunRa View Post
It's great to have the possibility of turning your PC into a digital crossover without the need of other conversion stages as it happens with Behringer for example.

Yep. I'd agree. That's what I felt to be tempting about this device too.

Though if you want to run a crossover and convolution engine, I'd opt for a headless Linux machine with brutefir driving such an interface.

In my case times are over where a Windows PC/Notebook is sitting right next to my stereo.

It's really a pity that this exa device is Windows only.
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Old 8th April 2011, 08:58 AM   #285
rsdio is offline rsdio  United States
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Originally Posted by soundcheck View Post
It's really a pity that this exa device is Windows only.
All we need to do is find a savvy CoreAudio programmer who is familiar with Apple's sample code for an audio device driver. For USB Devices, this can be User-land code, i.e., it doesn't even have to be a kernel driver.

It wouldn't hurt if this hypothetical CoreAudio guru were motivated by the DIY ethic.

I would do this myself, but I am quite busy designing my own USB hardware, firmware, and software. Thus, I'm afraid that if I took on the task, you poor DIY'ers would be waiting too long!
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Old 8th April 2011, 09:09 AM   #286
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Originally Posted by rsdio View Post
All we need to do is find a savvy CoreAudio programmer who is familiar with Apple's sample code for an audio device driver. For USB Devices, this can be User-land code, i.e., it doesn't even have to be a kernel driver.

It wouldn't hurt if this hypothetical CoreAudio guru were motivated by the DIY ethic.

I would do this myself, but I am quite busy designing my own USB hardware, firmware, and software. Thus, I'm afraid that if I took on the task, you poor DIY'ers would be waiting too long!
I see. You then must be considered EXA competition.

Let see if you gonna comply to USB 2.0 standards ( as touched upon earlier) once you're finished.

In this case we wouldn't need a "Core Audio" programmer.
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Old 8th April 2011, 11:22 AM   #287
rsdio is offline rsdio  United States
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Originally Posted by soundcheck View Post
I see. You then must be considered EXA competition.
Ha! (I see your smiley) Actually, I am working on this: the Madrona Labs "Soundplane A", which is not an audio device. It has on-board DSP and way more than 8 inputs and 8 outputs. The DAC is capable of 125 MHz sampling rates! But, I have no plans to compete with exaDevices any time soon. I prefer FireWire Audio anyway...

Quote:
Let see if you gonna comply to USB 2.0 standards ( as touched upon earlier) once you're finished.

In this case we wouldn't need a "Core Audio" programmer.
It is impossible for the exaU2I to implement USB-Audio unless the hardware is completely redesigned around a new chip. The FTDI Chip used in the exaU2I is incapable of implementing USB-Audio (which is what I assume you mean by "USB 2.0"). The FTDI Chip is locked to a specific USB Device type which is different than USB-Audio. Therefore, the only way for exaU2I to work on Windows or OSX is with custom drivers.

Note that "USB 2.0" refers to a wide range of devices, including the newer High Speed, but also includes the exact equivalent of USB 1.x Full Speed and Low Speed. Actually, USB 2.0 is a rather diluted term which has very little meaning unless specifically qualified. Lots of Full Speed USB-Audio Devices are technically USB 2.0, so you really have to be careful what you're buying.
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Old 9th April 2011, 09:13 AM   #288
SunRa is offline SunRa  Romania
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Thank you for the brief report. Would you mind elaborating on what are you using on the software side, what player, crossover app (if any) etc. That way we could have a more complete picture of what the set up is.
I am looking forward to learn more about your results.
Hi AR2, sorry for the late reply, only that I was so excited on putting the U2I to work that I missed some sleeping hours this week as I needed to build a DAC with AK4396, a chip I've never used before. However all the efforts paid off when the DAC finally locked on the U2I signal! And as I told in the previous post it was quickly obvious that I had something special in my hands.

I am only now beginning to learn how the U2I is interacting with the rest of the system. Listening impressions are also yet to come. I've used it briefly with cPlay on Windows7 and also with foobar. To early to tell if any differences yet.

The idea of using cPlay came actually when I wanted to listen some 384Khz/32bits files and I was not having any high quality downsampler installed in foobar (it was about 1.00 in the morning ). cPlay immediately recognized all the 8 channels of the U2I and after setting the SRC downsampler to 192Khz it just went playing music.

Regarding crossover software, the problem is that I don't have all the resources now to make some tests. I've been thinking at a proper USB implementation for multichannel streaming for years now (ever since peufeu, memeber of this forum, first posted in 2007 - 2008 an experiment with a spartan board streaming to a DAC through ethernet) and the exa board came out quite unexpectedly and when I was starting to loose my hope that we will see something else than two channel devices. Since peufeu's first developments, my goal became also finding a way to do crossovers on a PC environment and the U2I is kind of the device I always wanted to build/develop myself. It seems for now to do everything right: multichannel, galvanic isolation, huge sampling rates and bit depth and proper clock management system.

The challenge now will be to use crossover software able to work with ASIO. I would first look into the well known options in the market: Thuneau and Allocate and check how are these working. The solution KOON developed is also extremely interesting as it works with ASIO and I believe it could be modified for U2I. And while his system is limited to 44.1K, with U2I there are no sampling rate limits, not even with studio master files!

Also, there should be a way of using brutefir and integrate it with ASIO, I'll take a deeper look into the documentation available. I guess that this should be possible through a VST plugin and foobar definitely is capable of managing this, and I've noticed cPlay also seems capable of taking a VST plugin.

Believe it or not but I've even thought of convoluting off-line my entire music collection once I set-up my multichannel music system. Storage space I have plenty, and this would resolve the demanding task of doing real-time fir filters on 192/24bits and 384/32 bits files. Even with CUDA GPU's realtime fir filters on such large files is not an easy task.

Quote:
Yep. I'd agree. That's what I felt to be tempting about this device too.

Though if you want to run a crossover and convolution engine, I'd opt for a headless Linux machine with brutefir driving such an interface.
Soundcheck, any chances you could give us some more info regarding brutefir and asio? I know that you were hard at work into brutefir a couple of months ago when developing your system and brutefir player. Your input would be very helpful.

Unfourtunately for me a headless linux is not really an option, for the reasons above. Also, I really like Windows environment (I've toyed with linux also) and I like to have easy access to my music, movies and concerts and play them through the same system, at the same quality. I believe U2I is an excellent start for doing this. As I told earlier it's kind of a do it all solution, without compromising on some design principles and this I find really great!

Last edited by SunRa; 9th April 2011 at 09:18 AM.
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Old 9th April 2011, 09:54 AM   #289
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Is there pricing on the exa yet? And availability?


Cheers,

Fran
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Old 9th April 2011, 11:07 AM   #290
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Originally Posted by woodturner-fran View Post
Is there pricing on the exa yet? And availability?


Cheers,

Fran
Pricing is $430.00 according to the website.
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