Open-source USB interface: Audio Widget

[Turbon]

But I hate python...

Anyway, oscilloscope showed no sign of 12MHz - fixed - there was of course a short. Tried again on Linux and here is parts of the syslog from the time I press prog/reset and release the prog button.

---
Nov 24 13:42:46 Minty kernel: [ 7508.368096] usb 5-1: USB disconnect, address 32
Nov 24 13:42:48 Minty kernel: [ 7509.848042] usb 5-1: new full speed USB device using uhci_hcd and address 33
Nov 24 13:43:07 Minty kernel: [ 7529.200118] usb 5-1: USB disconnect, address 33
Nov 24 13:43:07 Minty kernel: [ 7529.440064] usb 5-1: new full speed USB device using uhci_hcd and address 34
Nov 24 13:43:07 Minty kernel: [ 7529.560075] usb 5-1: device descriptor read/64, error -71
Nov 24 13:43:08 Minty kernel: [ 7529.784046] usb 5-1: device descriptor read/64, error -71
Nov 24 13:43:08 Minty kernel: [ 7530.000051] usb 5-1: new full speed USB device using uhci_hcd and address 35
Nov 24 13:43:08 Minty kernel: [ 7530.120097] usb 5-1: device descriptor read/64, error -71
Nov 24 13:43:08 Minty kernel: [ 7530.344059] usb 5-1: device descriptor read/64, error -71
Nov 24 13:43:08 Minty kernel: [ 7530.560046] usb 5-1: new full speed USB device using uhci_hcd and address 36
Nov 24 13:43:09 Minty kernel: [ 7530.972086] usb 5-1: device not accepting address 36, error -71
Nov 24 13:43:09 Minty kernel: [ 7531.084064] usb 5-1: new full speed USB device using uhci_hcd and address 37
Nov 24 13:43:09 Minty kernel: [ 7531.492080] usb 5-1: device not accepting address 37, error -71
Nov 24 13:43:09 Minty kernel: [ 7531.492105] hub 5-0:1.0: unable to enumerate USB device on port 1

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Obviously there is a problem with the card...

Alex, you asked earlier for the full output from progwidget - that was the full output...

What about the physical USB ports? On this cheap Emachines E510 there is 3 USB ports 2 on the left and one on the right side. How would I know if they support "High speed"? In the control panel of vista there were a bunch of ordinary USB's and only 2 USB2 devices.

Now, I believe we have put enough focus on this one so I have ordered a tested and functional box from Borges (ship it fast Börge)... This one will be saved until the next time I feel to fix it. Thanks a lot for all the efforts you have put into it. Eventually I hope to post a note when it is working.

Brgds

[alexlee188]

Hi Turbon:

1. It is a good idea to order a tested and functional AB1.1 from Borge :-)
2. As for your Emachines E510, read the user manual etc. :-)
3. Even if the PC port is only USB1.0, the audio-widget should enumerate and work (at 44.1/48khz)
4. After you have fixed the 12Mhz XO problem, have you tried to re-flash with dfu-programmer?
5. If the earlier dfu-programmer output was only those you posted, there was something wrong - the flashing got stuck at the "erase" stage.
6. Try re-flashing again.

Alex

[Turbon]

Yupp, it feels like a good idea but still it nags me that it won't work.
Yes, I will RTFM...
Yes, the latest output is after fixing the 12MHz.
Yes, I tried again...

Thanks a lot Alex but I don't think we come any further with this one. I will order a new MCU or two - it will probably work right out of da box.

Brgds

[alexlee188]

Hi all,

I just tested the PurePlayer software for playback under Windows:

http://www.purediy.gr/downloads/pureplayer.zip

The sound quality is excellent and there is no extraneous noise when skipping tracks with audio-widgets.

Alex

[Turbon]

Now I bought Borges AB-1.1 and it arrived today, after some initial fiddling with it these are my findings:

1: I have to feed it at the bottom of the wave volume control in XP so I have aout 3 steps to silence. I can live with this as long I can keep output below 2VRMS.

2: This one is nicer. Whatever flacs I throw on it of the selection I posess, it plays them without a hitch. With UAC-1 I'm not supposed to have anything above - now there is different views of if it is 24/48 or 24/96. Never mind - I have 24/192's from reiable sources - vlc becomes a bit slow responding but sound is good. I first believed it was my very old SB Live! from about year 2000 that pranked me - I disabled it and checked where the AB-1.1 was connected on the amp - no problem there. A double check was the oscilliscope and indeed there was signal out...
So might the old SB drivers give it a boost, not to native UAC-2 but allowing it to playback 24/192? I would really want to know where my scheme glitches...

Brgds

[UnixMan]

Nope, likely the system is downsampling the stream on the fly. That also explain why v;c becomes slow (resampling may take a lot of CPU).

[Turbon]

You are quite right UnixMan, thanks.

[alexlee188]

You will find different players will give you different sound quality under Windows.

There are many factors at play:

1. Whether resampling occurs. Best SQ comes from no resampling.
2. Player software should run at highest "real time" priority. Do not run any other programs/processes at the same time.
3. Best player software loads the whole song into RAM and play from RAM. Disk access -> noise.
4. Drivers and options - ASIO, kernel mode streaming etc. only applicable to certain third party drivers.

I have found PureAudio player to give the best SQ under Windows. (but still not as good as mpd under Linux).

You have to experiment and find out for yourself.

Alex

[alexlee188]

PurePlayer I mean - see earlier post.

[RocketScientist]

@alexlee188 I certainly agree with factor #1. I don't agree with #2 unless you have a really marginal PC and/or can hear dropouts, ticks, glitches, etc. And I'll perhaps agree with #3 if you're using motherboard audio or an internal sound card. #4 seems like the least understood aspect.

Many (most?) players are making the exact same calls to the exact same APIs. And as long as they're delivering a bit accurate stream (i.e. no DSP, resampling, etc.) you'll get exactly the same sound (i.e. via DirectSound in Windows).

I have a USB protocol analyzer. It captures the actual packets being sent to an external USB DAC. And, guess what, it doesn't matter if I use Windows Media Player, Foobar, Media Monkey, VLC or my own custom software players. The exact same data gets sent to the DAC in Windows 7 with the volume set to maximum. And, by definition, that means all the players sound the same. I'm not saying some players don't screw things up somehow, but I can attest the ones listed above all deliver the same bits.

It would be interesting to repeat that test for Linux and OS X. I would expect the same results. That is, after all, what "bit accurate playback" is all about.

I would suggest the differences many claim to hear are either due to different settings, or they're just the usual well documented differences our brains serve up in sighted listening tests even when no differences really exist.