Pops with EMU 0404USB

[Ste77]

I have two DACs, one VDAC II and one EMU0404 USB both used with Pi via USB.
VDAC is playing smoothly any type of file while I noticed that with the EMU you hear pops and cracks with both MP3 and FLAC.
I've tried to increase buffer from 2048 to 4096 but no significant improvements.
Should I insist and further increase buffer? Do you think that is the issue?
Another theory I have is potentially related to the card itself since I'm not sure the EMU is a real asyncronous which could bring some noise/compatibility issue with USB transmission?
Then there is always the possibility of electrical disturb but why only with EMU and not with VDAC considering it's the same set up?
Any ideas/suggestions?

[janui]

Hi Ste77,
Please post the your debug information.

If it’s not possible to post it, just post the lines "audio_output { ... }", including all the lines between curly brackets. There could be more than one section beginning with "audio_output {", please post them all. And specify your Pi type and the image you are using.

Could you also tell us some more about when the "pops and cracks" occur, for example, only when number change, continuous, only some numbers, random, etc.
janui

[Ste77]

Hi janui
here you go:

audio_output {
name "bcm2835 ALSA"
type "alsa"
device "hw:0,0"
dsd_usb "yes"
auto_resample "no"
auto_format "no"
enabled "yes"
}

audio_output {
name "E-MU 0404 | USB"
type "alsa"
device "hw:1,0"
dsd_usb "yes"
auto_resample "no"
auto_format "no"
enabled "yes"
}

I'm still using PI first series with 0.3 beta but also have a Pi3 at home and planning to use it at some point in the future.
Regarding the pops/cracks, this is happening during playing, particularly evident for FLAC, but also some MP3 are affected.
This is not continuous but rather random.
Again, if I play the same tracks with VDAC, same set up, no pops/cracks at all.

[janui]

Hi Ste77,
USB Dac’s should be plug and play, the Linux ALSA subsystem should detect the card type and configure itself. Because the pops/cracks are continuous/random it indicates that USB Dac/ALSA handshaking and configuration has not completed correctly. I see two possibilities where this could go wrong:
1. ALSA has two commands for card mapping ‘device ”hw:<card number>, <device number>”’ and ‘device "plughw:<card number>, <device number>"’, there are differences in the way they work. The first uses an input = output scenario, the second forces ALSA output to be compatible with the output device (this may involve resampling or bit depth modifications).
2. The Pi 1 kernel is quite old and an upgraded version of ALSA may be required to make everything work with this Dac. If it works, this is the preferred solution as it will ensure bit-perfect processing.

1. Try modifying /etc/mpd.conf manually to replace the line ‘device ”hw:1,0”’ with ‘device "plughw:1,0"’. When you next reboot this file will be restored to the standard settings, you will also lose any configuration details which you entered in the MPD screen.
Access the Pi with SSH. First make the file writeable with:

Code: Select all

chattr -i /etc/mpd.conf

Then edit the file to substitute the line ‘device ”hw:1,0”’ with ‘device "plughw:1,0"’ with nano:

Code: Select all

nano /etc/mpd.conf

In your Rune web interface go to the /dev page (URL: runeaudio.local/dev). There is an option in the lower half of the screen ‘mpdrestart’, click this. Then test…
If this works there are potentially some complications concerning sound quality. Report back, some more tests are required.

2. Try using this image with your Pi 1, it was built for the Pi Zero but should work on all single processor Pi’s: raspberry-pi-zero-support-in-0-4-t3711-70.html#p20577
Then test…

If this doesn’t work try modifying /etc/mpd.conf in the new image.

janui

[hondagx35]

Hi,

you have both outputs enabled at once this is to much for the Pi1.
Go to the MPD page and select "Analog" and then back to your USB DAC.

Frank

[janui]

Thanks Frank,
Missed that.
janui

[Ste77]

Hi both
I went for option 2 installing the suggested image and making sure the EMU is the only selected output.
Definitely MUCH BETTER.
All pops disappeared.
Thank you guys!