[PROBLEM] Cyrus soundkey intermittent distortion

[leicray]

I'm curious why u chose the older 2B and not a 3B+?

Two reasons. I already have a 2B which I know works with fine with my Audiolab M-DAC and with the Cyrus soundKey. Secondly, I was able to purchase a brand new & sealed 2B on eBay for GBP18, including delivery, which is approximately USD23.40. Seemed like a good price.

[vinnn]

I've had a Cyrus Soundkey for a couple of years which has featured the aforementioned nasty tearing sound after resolution/sample rate switching.
It used to occur on USB Audio Player Pro (Android) until a patch was made to the UAPP driver. The Soundkey was mainly used on my phone but is hooked up to my desktop computer running Fedora Workstation nowadays. The tearing noise doesn't occur on Fedora but I've only used the Soundkey on the desktop for a couple of months.

I'm thinking it's likely to be driver issue with a quirk of the Soundkey that has probably been addressed in a newer alsa version than is what is in moOde. My Fedora 31 system currently has alsa-lib 1.2.2 whereas my moOde 6.4.2 system is showing alsa-lib 1.1.8.

[leicray]

It's reassuring to know that I'm not the only person to have experienced this particular problem. Furthermore, your description of a "nasty tearing sound" captures exactly the nature of the distortion.

The audio files that I am playing are mostly in FLAC format (CD rips) and are probably encoded using VBR which might well be triggering the distortion. If I can find the time, I might try re-ripping some tracks using FBR for a comparison. I do find that if I allow a track to play after the onset of distortion then it will often "correct" itself and the distortion disappears.

Perhaps the solution is for Tim to update alsa-lib to the latest version in the next version of moOde.

Thanks for sharing your insights.

[Tim Curtis]

Remember that FLAC is decoded to PCM. Your audio device only receives PCM from ALSA.

You mentioned in an earlier post that your tests indicated that issue you experienced on a Pi-4B does not occur after swiping in a Pi-2B. http://moodeaudio.org/forum/showthread.p...2#pid17262

This would suggest the issue is most likely in how the Pi-4B USB ports work with the kernel USB audio driver.

-Tim

[TheOldPresbyope]

At the risk of sounding like a curmudgeon (but, wait, I am one), I don't see the point of beating this horse any longer. I'd think Cyrus has the lead here.


And to reassure others who may read the posts upthread about RPi4B firmware, moOde is grounded in Raspbian and inherits its automatic run of rpi-eeprom-update at each boot (look at the service settings or grep the syslog after a boot). Both my RPi4Bs, one 2GB and one 4GB model, purchased at different times, report they are running current versions.

Regards,
Kent

[Tim Curtis]

Woah, I don't know there was an auto eeprom updater.

Code:

pi@rp2:~ $ sudo rpi-eeprom-update
BCM2711 detected
BOOTLOADER: up-to-date
CURRENT: Tue 10 Sep 10:41:50 UTC 2019 (1568112110)
LATEST: Tue 10 Sep 10:41:50 UTC 2019 (1568112110)
VL805: up-to-date
CURRENT: 000137ad
LATEST: 000137ad
pi@rp2:~ $

I think prolly best to just leave this enabled :-)

[boring]

I also experience intermittent distortions with Moode and Vinshine DAC (Amanero USB receiver). I tried kernel version 4.14 with gentooplayer and there is no distortion. Intermittent distiortion happens with kernel 4.19 also with Gentooplayer.

[michaelagiles]

I had a similar issue with a Pi3b and IQ audio PiDac+ - regular but short (2 secs?) bursts of noise/distortion. It turned out to be the WiFi "searching" for a connection and producing RF interference in a badly shielded pre-amp. I think! Since I was using ethernet connection, it disappeared when I turned off the wifi.
Just a thought!
MG

[GStevens]

I've just found this thread which identifies the same problem that I am experiencing with a Cyrus Soundkey. I'm using a Pi 4B with 8GB RAM, with the DAC plugged in to a USB 3 socket. The distortion usually occurs for a few seconds and then disappears again, usually a minute and a half or so into a track. The problem occurs using Eterhet and Wireless. No such distortion is heard if I skip the Cyrus DAC and just use the headphone socket on the Pi.

Did anyone ever get to the bottom of why this occurs?

TIA,
Geoff

[GStevens]

Further to my previous email, I have contacted Cyrus, with the following rersponse:

We don’t officially support any Linux distribution as there are too many variables. As a starting point, in the distribution you are running, have a look how much latency the GPIO kernel module is adding. As the soundKey is an asynchronous device, if there is too much latency between packet request and receive, data corruption can occur which sounds like you describe. Again, we don’t support Linux, so please use these points as a steer to find out more on sites such github or raspberrypi.org

Is there anyway to change the latency?

Geoff