Announce: Enhanced Digital Output app - USB Dac and 192k Digital Ouput

[cfraser]

Why is it that people always have to have ONE answer to everything? Must be something we're kind of taught or brought up with (I won't go to the R-word place), there's certainly no logic to it or demonstration of it in nature.

I mean really, how trivially simple and fast is it to remove/re-install TT3 on the fly? The feature is built-in. Or this EDO too, if you don't like it?

People have gone to the trouble to give us *options*, at no cost too. Take it like an educated adult and quit whinging.

[leoduran]

Why is it that people always have to have ONE answer to everything? Must be something we're kind of taught or brought up with (I won't go to the R-word place), there's certainly no logic to it or demonstration of it in nature.

I mean really, how trivially simple and fast is it to remove/re-install TT3 on the fly? The feature is built-in. Or this EDO too, if you don't like it?

People have gone to the trouble to give us *options*, at no cost too. Take it like an educated adult and quit whinging.

Well, I'm also having a difficult time understanding what the root-cause for the "perceived" issues may be.
At least in the case of using "Async USB", the work is being done at the DAC; with the SBT simply "passing" buffers to the DAC.
So, it's a real "head scratcher" to me in how the SBT+EDO can make music sound "more digital" or "less analogue", while using Async-USB.

My understanding is that the EDO is really intended to leverage the USB2.0 port on SBT for supporting "Async USB" (USB2) DAC's up-to 24/192K... And for that, I don't think there's need for TT3.0 (but perhaps I'm missing something?)

Having said all of that, perhaps there are issues with the S/PDIF outputs (Coax or optical) once EDO is installed... And, to be honest, I have not done enough testing to speak to that (other than to say that I have not noticed any degradation... but frankly, I was not really doing rigorous testing).

So, to be fair, I think it is appropiate to ducument observations, even if they do sound like "whining" (as negative as they may seem, if the observations can help indentify "real" issues, and if issues are root-caused & fixed as a result, we'll be better off for it).

So, I'd say, keep pertinent comments coming; but please do try to do some diligence, to avoid wasting everyone's time... Especiallly Triode.

And thanks again to Triode for all the hard work he's done so far.

[dsdreamer]

I upgraded from 0.1 to 0.2 via the up-date all menu option on the Touch. I was able to play via an AudioEngine D1 at 44.1, 88.2 and 96kHz, connected via an ac-powered hub to the Touch. I switched the DAC off via the front panel button, waited a few seconds powered it back on and verified that I could play music.

A strange thing happened after leaving both Touch and DAC powered on for the duration of my day at work. After coming home I found I could not play music, even though both devices were still powered on from this morning's experiments. I further noted that the USB hub's green indicator light corresponding to the DAC was not lit. Power cycling the DAC didn't cause it to be recognized, either. Nor did completely unplugging the device from the hub and plugging it back in. Finally, I pressed the reset button on the Touch and waited for the reboot to complete. The green light on the hub corresponding to the DAC came back on, and music started playing.

I am not sure whether the above experience means something has changed, or whether I was just unlucky this particular day.

Anyway, thanks to Triode for this latest advance. I'll keep my eye on it to see if I ever get a repeat of losing communications to the DAC over USB.

[AJ24hours]

Current setup consist of:

SB touch with Enhanced Digital Output app...no issues at present (played various high rez files from SD card)
Emotiva XDA-1, connected as a DAC full volume, NOT as a preamp
Lifatec Toslink Silflex Glass optical cable
DALI Zensor 1 Loudspeakers
Trends T-amp 10.1 modified

Currently, it's sounding great or should I say amazing!

I've posted a new applet to the 3rd party apps list for Squeezebox Touch. This is designed to enhance the digital output capabilities of the device for use with external Dacs. It is based on the software which people have helped me test on the "Async USB Dac Experiments" thread but should now be suitable for less experienced users to install.

The app should add support of the following to your Squeezebox Touch:
- External USB dacs using either USB audio class 1 or 2 protocols [USB 1 dacs normally state they support up to 96k sample rates, USB 2 dacs normally state up to 192k]
- Support of 176 and 192k playback via the standard digital output

There are a number of limitations to be aware of:
1) USB 1 dacs which operate in asynchronous mode probably need an external high speed hub to work without "clicks" - this is due to what appears to be a limitation in the Touch hardware. It is completely resolved with a cheap (<$10) bus powered hub connected between the dac and squeezebox. There is a workaround option which works with some dacs if a hub is not used, but it limits playback to 44/48k sample rates. At present is has only been proved to work with Audiolab/Lakewest dacs.
2) USB support does not yet support hot plugging of usb dacs - please connect your dac and leave turned on at present [this is likely to improve in future]
3) 192k playback requires a dac which supports it and is only supported with flac files using native decoding at present. [In future 7.8 LMS and firmware should support 192k wav streaming] It will also require sufficient bandwidth on your network.
4) Only one output can be selected at once, this means when a USB dac or the Digital Output are selected there will be no sound on the analog outputs.

The app is called "Enhanced Digital Output" and is the main 3rd party apps list.

To install, please following the following steps:
1) Ensure your Squeezebox Touch is running 7.7.x or later firmware
2) Go to Apps Gallery -> 3rd Party Apps on the touch screen
3) Deselect the "recommended applets only" option, so that you see a longer list of apps
4) Select "Enhanced Digital Output" and select it for installation
5) Your touch should download the app, reboot, then download a new custom linux kernel and reboot again
6) You should now get a list of possible output devices - this should include "Digital Output" and your USB Dac if it is plugged in, select the appropriate output
7) Touch should reboot again and then be ready to start playing with the selected output

If you want to change the output go to Setting > Audio Settings > Digital Output; if you want to change some of the advanced options go to Settings > Advanced > Digital Output

Please note that if you perform a firmware update, then the app and kernel will need to be reinstalled, this should be automated just requiring you to install the app again or to have the "reinstall after update" option selected from the 3rd party apps list.

Please post your feedback on this thread - I would like to create a list of USB DACs which are known to work with it, we started that on the experiment thread, but I think it would be cleaner to maintain a list here.

[Kuro]

Well, I'm also having a difficult time understanding what the root-cause for the "perceived" issues may be.
At least in the case of using "Async USB", the work is being done at the DAC; with the SBT simply "passing" buffers to the DAC.
So, it's a real "head scratcher" to me in how the SBT+EDO can make music sound "more digital" or "less analogue", while using Async-USB.

There are actually three factors that affect the sound of a USB DAC:

1. The ground noise transmitted from the PC to the USB DAC via the ground connection;
2. The USB DAC's receiver code;
3. The USB host's transmitter code.

The DAC's clock jitter increases if ground is contaminated by the noisy ground from the PC. This is why some newer USB DACs have galvanic isolation on the USB port to prevent ground noise contamination.

The receiver code does make a difference in sound. The most famous one is Streamlength by Wavelength audio. An IC chip with a steady running state will emit less noise on the supply line. A better receiver code will lower the noise emitted by the receiver IC. Likewise for the code in the USB host. More interruptions in the host will cause the receiver to pause and leave its steady state. This will create more noise by the receiver IC.

[NoRoDa]

Great work, Triode! I am impressed.



Istalled it just to test if it works in my setup. (the .2 version)

ReadyNAS Ultra4 running LMS 7.7.2 --> stock SBT wlan 7.7.2. --> BJC coax --> Rega DAC
No problems playing 24/96 and 24/192. Just a flashing lock indicator and a bit of noise in the speakers when playing 24/176.4 but that's an issue with my DAC. SNR 666.

The difference for me using coax is that the 192kHz files are now streamed to the SBT directly without beeing downsampled through sox to 96kHz?
I still haven't heard of anyone beeing able to tell 96kHz from 192kHz when listening, so I'm not shure if this tweak is really important for us using the coax output.
(People listening blind that is, not the guys in here that are able to hear the angels sing...)
For USB DAC users it's a winner. (Not for me though, since the USB input of the Rega DAC is limited)

Tried to just disable the EDO without doing a factory reset, and it works. (--> Plays 192kHz and 176.4kHz as 96kHz, according to the diodes on my Rega DAC)
Earlier posts in this thread says I have to do a factory reset? Is that correct?



This EDO from Triode works like it's an integrated part of the stock SBT. No loss of user interface or display/remote. Great!
For me the question is if it's worth the effort to convert my 176.4kHz albums to 192kHz or 96kHz og just leave it and have LMS downsample everything to 96kHz....

Regards

[Lemmi]

I've just posted and updated version of the app. The kernel is unchanged, so if you install over the top of the previous install it will not need to download a new kernel.

Changes in this version:
- ability to turn usb dacs off and then on again without rebooting touch [note: the dac must still be on when touch is rebooted]
- simpler information screen for usb dacs which is hopefully easier to read [note: this only works if you have not turned the dac off and then on again since touch rebooted]
- some changes to the installation process which should reduce cases where resetting to factory defaults was necessary

Please try and post feedback on this thread.

Hello together; working with Synology 409 SLIM and Logitech Touch. I have flacs from Linn and 2L with 192/24. Some File will send the touch to buffering.
I set the server app on the 409 Slim to higher CPU. The cpu, the RAM and also the LAN works in the limits. Anything I can do to get it working without buffering ?

Thanks Triode for making a really good job

[adamdea]

There are actually three factors that affect the sound of a USB DAC:

1. The ground noise transmitted from the PC to the USB DAC via the ground connection;
2. The USB DAC's receiver code;
3. The USB host's transmitter code.

The DAC's clock jitter increases if ground is contaminated by the noisy ground from the PC. This is why some newer USB DACs have galvanic isolation on the USB port to prevent ground noise contamination.

The receiver code does make a difference in sound. The most famous one is Streamlength by Wavelength audio. An IC chip with a steady running state will emit less noise on the supply line. A better receiver code will lower the noise emitted by the receiver IC. Likewise for the code in the USB host. More interruptions in the host will cause the receiver to pause and leave its steady state. This will create more noise by the receiver IC.

As I understand it Triode has asked to keep the analysis of whether and if so why the EDO may make a difference to sound quality off this thread. I think we should respect his wishes for lots of reasons, not least because he makes no claims on the subject.

[ozzymilton]

Well really, whinning ?
It is great that someone placed the free App for the upgrade, but the OP was looking for opinions, at least intially.
Is this upgrade designed only to enhance the USB ?
If not then the OP might need the information that its not helping the digital outputs such as the coaxial output?
And if the Enhanced digital Output does not improve the sound quality, then what's the Point?

[bobertuk]

Well really, whinning ?
It is great that someone placed the free App for the upgrade, but the OP was looking for opinions, at least intially.
Is this upgrade designed only to enhance the USB ?
If not then the OP might need the information that its not helping the digital outputs such as the coaxial output?
And if the Enhanced digital Output does not improve the sound quality, then what's the Point?

I think the point of the App was to allow those with USB only DACS to use them with the Touch - I believe there are also advantages gained by using Asynchronous DACs. An added bonus is that it also allows user with non-USB DAC to use their DAC via Optical/Coax to play 192k audio files. Triode hasn't made any claims that there is improved sound quality. The App allows the Touch to be a more flexible audio streaming device.

Bob