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-   -   exaU2I - Multi-Channel Asynchronous USB to I2S Interface (https://www.diyaudio.com/forums/exadevices/183374-exau2i-multi-channel-asynchronous-usb-i2s-interface.html)

UnixMan 18th February 2011 02:32 PM

Linux?
 
What about Linux/ALSA driver support?

glt 18th February 2011 04:35 PM

A couple of comments/questions:

1- Any thoughts of using bulk mode transfer instead of iso-asynch?
2- In your testing with Sabre32, are you using the lowest setting for DPLL?

exa065 18th February 2011 08:20 PM

Quote:

Originally Posted by NeoY2k (https://www.diyaudio.com/forums/exadevices/183374-exau2i-multi-channel-asynchronous-usb-i2s-interface-post2473761.html#post2473761)
Hello,
Thanks for your message on my previous thread.

You don't seem to use USB Audio 2.0 standard, as you don't have OSX compatibilty yet. I'd be happy to know how you made it :)

As a sound engineer, and now also a guy working for major brands of professionnal audio equipment, I can tell that FireWire is DEAD. Even for pro! USB is not dead: just old. USB 3.0 is of some interest. Some.

FireWire was an excellent idea. It (almost) never was correctly implemented. Compatibility issues were paramount. Finally, even Apple ditched it out of most it's products, even Macbook Pros! Developping FireWire equipment now is a nonsense. Its benefits have to be transferred to another technology that has a longer potential life.

USB is the standard. And, if designed correctly, there is no clocking problem. Ask MOTU's designers...

Where we really are heading is convergence. Network. TCP/IP Ethernet.
Just have a look at what Dante for pro audio does, Ethersound is also going native...

Didn't you just said Ethernet a few posts ago?

There is no open protocol for consumer audio streaming over TCP/IP (and especially WiFi). If you can do it, if you can have automatic delay compensation somehow for when the user is looking at videos, then... Then you'd probably better team with a few other guys, and sell a few trucks of these.

NeoY2k,
I agree with your thoughts and I am going to explore the issues of using standard network protocols and controlling latency for video. I was considering streaming the sound data over Ethernet. USB was easier and safer for the first release. I will be moving to USB 3.0 eventually. Right now I can do "only" four channels at 352.8 kHz.

exa065 18th February 2011 08:35 PM

Quote:

Originally Posted by qusp (https://www.diyaudio.com/forums/exadevices/183374-exau2i-multi-channel-asynchronous-usb-i2s-interface-post2473338.html#post2473338)
where do i sign? you might also drop acko a line as he has full 8 channel es9018 dac kit available shortly. he may offer your solution as part of the range of modules. are you also looking at integrating a digital xo as part of your mcu?

ackolabs

My website will be released soon. :)

For now I will stay focused on the interface - driver and hardware to get the data delivered to a DAC.

My understanding is that the digital XO is usually a plug-in for the player - for example Foobar. Do you want to see the XO as a plug-in for the ASIO driver? What would be the reason for that?

exa065 18th February 2011 09:14 PM

Quote:

Originally Posted by greggp (https://www.diyaudio.com/forums/exadevices/183374-exau2i-multi-channel-asynchronous-usb-i2s-interface-post2473366.html#post2473366)
Have you tested with other applications, like Windows 7 Media Center, VLC Media Player, or Media Player Classic - Home Cinema?

I'm curious how your drivers handle playback of DVDs and Blu-rays (either BD discs, images or MKV files). If you are going to support multichannel, it obviously needs to support these formats.

How is the device listed in Control panel, does Windows see this as a multichannel device?

Do you have any mixer control. Is it possible to control the volume of individual channels and is there a master volume control?

What about USB2 Audio Class 2.0 drivers? Supported in OSX and Linux. Hopefully Microsoft will support USB2 Audio Class 2.0 in the future. I was holding my breath, but had to exhale.

I am using Foobar and J. River Media Center. Both players can cover almost all lossless audio formats. J. River can play most video formats, including DVD and MKV. Both players can do multichannel audio and automatic sampling rate switching.

Iíve also tested Winamp and Media Monkey. Unfortunately the ASIO output plug-ins for the last two are not very stable. There is also an open source project about ASIO plug-in for Windows Media Player and Windows Media Center. I couldnít make it work. There are other ASIO capable players out there, I haven't tested them.

Itís a pity that VLC Media Player, and Media Player Classic - Home Cinema have no support for ASIO.

The remaining questions in your post are very important. I need many pages to explain the way ASIO works and the benefits of using ASIO for audiophile-grade multichannel playback. Some of it will be on my website Ė to be released soon.

I will try to continue my reply to you ASAP.

exa065 18th February 2011 09:32 PM

Quote:

Originally Posted by tdtsai (https://www.diyaudio.com/forums/exadevices/183374-exau2i-multi-channel-asynchronous-usb-i2s-interface-post2473649.html#post2473649)
It's seems very interesting. What USB Chip you use on your board? Does your project only support output? I suggest you reference XMOS USB Audio Class 2.0 reference design or C-Media CM6632 USB Audio Class 2.0 reference design. All two company's product can do what you want to do except 352.8K output.
I had some experence in develop USB Audio device driver in windows and Mac. If you need help you can PM me too.

Thanks for offering help. OS X seems to be a hot topic. For now I have to go one step at the time.

The project supports only outputs. It is meant for high-end music playback.

I am using a FTDI USB. I am not using any third party reference designs Ė the hardware (FPGA core) is designed in-house from scratch.

exa065 18th February 2011 09:36 PM

It is on the to-do list for the next version.

rsdio 18th February 2011 10:20 PM

Quote:

Originally Posted by glt (https://www.diyaudio.com/forums/exadevices/183374-exau2i-multi-channel-asynchronous-usb-i2s-interface-post2473935.html#post2473935)
Any thoughts of using bulk mode transfer instead of iso-asynch?

That would be a very bad choice. Bulk mode transfer does not guarantee the bandwidth, and thus you would have audio dropouts at any time. Bulk is only appropriate if you wanted to download a music file to a standalone player for later playback, not for real-time playback.

Iso-Asynch is the only choice for audio. If your operating system enables the device, then bandwidth is guaranteed. For Full Speed USB, this is 8.192 Mbps, for High Speed USB, it's something like 200 Mbps. If bandwidth is not available for some reason, then you will get an error message instead of dropped audio.

exa065 19th February 2011 03:15 AM

Website Launched
 
The project website is now released. I would like to invite you to visit www.exaDevices.com - the home of the exaU2I Interface.

Thank you for your feedback. Iíve tried to answer your questions on the website. More content will be up soon.

I hope to make the device available within 15 days.

exa

glt 19th February 2011 03:20 AM

Quote:

Originally Posted by rsdio (https://www.diyaudio.com/forums/exadevices/183374-exau2i-multi-channel-asynchronous-usb-i2s-interface-post2474344.html#post2474344)
That would be a very bad choice. Bulk mode transfer does not guarantee the bandwidth, and thus you would have audio dropouts at any time. Bulk is only appropriate if you wanted to download a music file to a standalone player for later playback, not for real-time playback.

Iso-Asynch is the only choice for audio. If your operating system enables the device, then bandwidth is guaranteed. For Full Speed USB, this is 8.192 Mbps, for High Speed USB, it's something like 200 Mbps. If bandwidth is not available for some reason, then you will get an error message instead of dropped audio.

The Musiland driver is bulk mode and it is good for 24/192. When you have plenty of bandwidth then bulk mode guarantees data delivery.


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