[PROBLEM] Smsl D300 Dac - loud "pop" noise before playing the first song

[happymax]

Hello,

yesterday I connected my new Smsl D300 dac via usb to the RPI4 where moOde 7.6.1 is installed and only when I play the first song after switching on before the music is played do I hear a loud "pop" noise from the speakers; the only way not to hear this noise is to reduce the volume to zero from moOde, activate the first song and then after a second turn up the volume.

All subsequent songs are played correctly without any starting noise.

In the MPD configuration the parameters are the following:

Audio Output
Output device: SMSL USB AUDIO
Volume Type: Software
DSD Support Format:
Native DSD
Silence before stop: NO
TheSycon workaround: NO

It almost seems that the MPD performs a restart before playing the first song but this is just my feeling.


Thank you very much for helping

[Sehnsucht]

Hello,

yesterday I connected my new Smsl D300 dac via usb to the RPI4 where moOde 7.6.1 is installed and only when I play the first song after switching on before the music is played do I hear a loud "pop" noise from the speakers; the only way not to hear this noise is to reduce the volume to zero from moOde, activate the first song and then after a second turn up the volume.

All subsequent songs are played correctly without any starting noise.

In the MPD configuration the parameters are the following:

Audio Output
Output device: SMSL USB AUDIO
Volume Type: Software
DSD Support Format:
Native DSD
Silence before stop: NO
TheSycon workaround: NO

It almost seems that the MPD performs a restart before playing the first song but this is just my feeling.


Thank you very much for helping

This might not be a MoOde/mpd problem. Have you ruled out this simply being what the DAC always does by connecting it to another pc, phone etc?    The Topping E30 DAC does this too (when turned on, when switching between bitrates etc).

[Tim Curtis]

Try setting MPD to Hardware volume.

[happymax]

Try setting MPD to Hardware volume.

Thanks Tim for your reply.

I made this change but it didn't fix the problem.

[happymax]

This might not be a MoOde/mpd problem. Have you ruled out this simply being what the DAC always does by connecting it to another pc, phone etc?    The Topping E30 DAC does this too (when turned on, when switching between bitrates etc).

Thanks for your replay.

Unfortunately the "pop" is really loud and I wanted to know if there was a solution to be able to eliminate it.

[DRONE7]

Not sure this will have the desired effect though there is some discussion and may be worth trying.
ALSA Power Management (DAPM) mutes and un-mutes for power-saving( generally for battery powered devices)

The 5 seconds delay before mute is turned on comes from the DAPM pmdown time. Main reason for this delay is to avoid clicks when a device is closed and then shortly after that opened again.

one suggestion is to create a file called snd_soc_core.conf in /etc/modprobe.d with this line in it:

Code:

options snd_soc_core pmdown_time -1

This disables DAPM 
You could try  and report results.

An alternative suggestion is to create a file /etc/modprobe.d/pmdowntime.conf with the following content

Code:

options snd_soc_core pmdown_time=600000

This increases the time between muting events

[happymax]

Not sure this will have the desired effect though there is some discussion and may be worth trying.
ALSA Power Management (DAPM) mutes and un-mutes for power-saving( generally for battery powered devices)

The 5 seconds delay before mute is turned on comes from the DAPM pmdown time. Main reason for this delay is to avoid clicks when a device is closed and then shortly after that opened again.

one suggestion is to create a file called snd_soc_core.conf in /etc/modprobe.d with this line in it:

Code:

options snd_soc_core pmdown_time -1

This disables DAPM 
You could try  and report results.

An alternative suggestion is to create a file /etc/modprobe.d/pmdowntime.conf with the following content

Code:

options snd_soc_core pmdown_time=600000

This increases the time between muting events

Thanks for your suggestion!

I'll try this weekend and then I'll let you know.

[happymax]

I report the results of my tests.

First I wanted to clarify that even if I set the volume to zero from moOde, the loud pop noise is still produced by the speakers before moOde play the first song; to eliminate the problem I have to set the volume to zero of the amplifier.

I ran the following tests without solving the problem:
- fresh installation of version 7.6.1
- configuration changes as suggested by @DRONE7 

To verify that the Smsl D300 dac did not have any hardware failure I installed Foobar 2000 and the dac drivers on a pc with windows, and loud pop noise does not occur.

At this point I think that Raspi Ios or moOde generate the noise when the communication with the dac is activated before sending the data of the first song; maybe there is some incompatibility with the usb port of the dac or something else that windows manages through the Smsl drivers.

Do you have any suggestions for further checks?

Thanks

[Tim Curtis]

Very odd. When you set moOde volume to 0 what is ALSA volume?

Code:

amixer -c2

In any case the fact that there is no glitch with Foobar player and the smsl USB drivers suggests a bug in the usb audio driver in Linux or possibly an issue with the USB stack on the Pi.

Upcoming moOde 8 is based on a newer version of RaspiOS, the "Bullseye" release, and the 5.10.y or later Linux kernel. Maybe this platform will not produce the glitch.

[happymax]

Very odd. When you set moOde volume to 0 what is ALSA volume?

Code:

amixer -c2

In any case the fact that there is no glitch with Foobar player and the smsl USB drivers suggests a bug in the usb audio driver in Linux or possibly an issue with the USB stack on the Pi.

Upcoming moOde 8 is based on a newer version of RaspiOS, the "Bullseye" release, and the 5.10.y or later Linux kernel. Maybe this platform will not produce the glitch.

Thank you Tim for the info about the new release.
This is the output:

Code:

Simple mixer control 'SMSL USB AUDIO ',0
  Capabilities: pvolume pswitch
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 127
  Mono:
  Front Left: Playback 127 [100%] [0.00dB] [on]
  Front Right: Playback 127 [100%] [0.00dB] [on]
Simple mixer control 'SMSL USB AUDIO ',1
  Capabilities: pvolume pvolume-joined pswitch pswitch-joined
  Playback channels: Mono
  Limits: Playback 0 - 127
  Mono: Playback 127 [100%] [0.00dB] [on]

moOde is my reference player, I will never change it; thank you for your immense commitment to this project!